ORIGINAL_ARTICLE
DYNAMICS OF PITCHING CONTROL MECHANISM OF SMALL PROPELLER-TYPE WIND MACHINES
The paper is aiming at exploring the area of pitch control . type of regulation used in small propeller-type wind machines. To cover the lack of published information about the real design criteria of such type of regulation, this work is carried out to develop the pertaining theoretical data-base. The paper investigates the dynamic performance of the centrifugally-activated pitch control mechanisms widely-used in wind machines. A typical pitching mechanism is chosen to be the subject of analysis; namely the crank-slider-crank mechanism which is centrifugally-activated by hub-mounted fly weights. The kinematic and dynamic characteristics of the candidate system are fully analysed. The results are presented in a group of charts in terms of the system dim-ensionless design-parameters, best suiting the engineers for design purposes.
https://amme.journals.ekb.eg/article_56797_ee0ec5c7019138953fe864f16d89071e.pdf
1986-05-01
89
103
10.21608/amme.1986.56797
ATEF
HASSANEIN
1
Associate Professor, Dept. of Aeronautics, Faculty of Engineering, Cairo University, Giza, Egypt.
AUTHOR
FATHY
EID
2
Colonel Engineer, Head of Quality Dept., EAF Helwan 0/H Depot, Ph.D. Student, Dept. of Aeronautics, Cairo Univ.
AUTHOR
ORIGINAL_ARTICLE
AXISYMMETRIC VIBRATION OF STEPPED ANNULAR PLATES
Free axisymmetric vibrations of annular stepped plates have been studied on the basis of the classical theory of plates. Applying the uniform plate solution to each zone of different thickness; considering the continuity and boundary conditionslyielda a system of eight equations. Frequency determinants of such plates,with diff-erent step radii, are derived for various combinations of boundary conditions. Consequently the values of the resonant frequencies of the first two symmetric modes are calculated. Different graphs are included to facilitate the use of this material for design purpose.
https://amme.journals.ekb.eg/article_56799_af7c78c116ca9c616da19234864c0ca1.pdf
1986-05-01
105
114
10.21608/amme.1986.56799
Transvers vibration
annular plates
stepped circular plates
boundary conditions
natural frequency
symmetric modes
M.
SHEBL
1
Assistant Frof.,Mechanical Design Dept.,Faculty of Engineering and Technology,Helwan University,Cairo,Egypt.
AUTHOR
ORIGINAL_ARTICLE
DESIGN CHARTS FOR VIBRATING THREE LAYERED BEAMS WITH VARIOUS BOUNDARY CONDITIONS
The paper presents comprehensive design charts to be used for optimal selections of multilayered beams with elastic faces. Model deflections and bending were computed through the range of the geometrical and shear parameters which cover soft and stiff core materials. The results include the first three eigen frequencies for four combinations of end conditions of interest in bridge, space-craft and machine designs. The computer aided investigation considered the relative merits with respect to the simple homogeneous beam.
https://amme.journals.ekb.eg/article_56802_aae7b867e40e999798b52e046f95c234.pdf
1986-05-01
115
123
10.21608/amme.1986.56802
S.
Farghaly
1
Assistant Professors, Mechanical Design Department, Faculty of Engineering and Technology, MATARIA, Helwan University, Cairo, Egypt.
AUTHOR
Y.
Younes
2
Assistant Professors, Mechanical Design Department, Faculty of Engineering and Technology, MATARIA, Helwan University, Cairo, Egypt.
AUTHOR
R.
Gad El-Rab
3
Graduate. Student, Mechanical Design Department, Faculty of Engineering and Technology, MATARIA, Helwan University, Cairo, Egypt.
AUTHOR
ORIGINAL_ARTICLE
COMPLETE FORCE-BALANCING AND SHAKING MOMENT OPTIMIZATION OF THE RGGR SPATIAL MECHANISM
An RGGR spatial mechanism with constant input speed and arbitrary link dimensions is considered. The coupler is a thin straight rod. The masses of the moving links are distributed so that the centre of their total mass is stat-ionary throughout the mechanism cycle to insure that the resultant shaking force transmitted to ground due to the inertia effects on the moving links vanishes. This is achieved by fixing two balancing weights to the input and output links. The balancing weight attached to the ouput link is a solid cylinder with the greatest feasible length, and with the axis of rotation of the output link coinciding with one of the generators of its cylinderical surface. The parallel plane sides of this balancing weight are, in general, inclined to its axis. Both balancing weights are so designed that the Root-ivlean-Square shaking moment arising from the force-balanced mechanism is minimum. Anumerical example is presented.
https://amme.journals.ekb.eg/article_56803_9297916d77e91dedba0c262b28080927.pdf
1986-05-01
125
139
10.21608/amme.1986.56803
M.
Hedaya
1
Lecturer, Department of Design and Production Engineering, Faculty of Engineering, Ain Shams University, Cairo, Egypt.
AUTHOR
ORIGINAL_ARTICLE
ELIMINATION OF THE FLUCTUATION OF THE INPUT TORQUE OF PLANAR MECHANISMS BY SPRING-CAM SYSTEM
The paper proposes the use of a cam with a reciprocating or oscillating follower for the elimination of the fluctuation of the torque input to a planer mechanism. The cam is fixed to the input shaft, which is rotating at a uniform speed, and the follower is maintained in contact with the cam by means of a spring. The expression of the input torque, which is required to drive a planar mechanism at a constant input speed, with the output leads and inertia forces considered, is derived. The cam profile is designed such that the cam input torque counters the fluctuating part of the mechanism input torque. This condition is employed in deriving the cam design equation, which is a differential equation describing the follower dsplacement. A special numerical method is proposed for the solution of this equation. Also, a formula is derived for the contact force between the cam and follower. This formula is applied at different mechanism positions, after the solution of the cam design equation, to check the contact between the cam and follower. The proposed method is applied to a four-bar linkage by using a disc cam with an oscilating follower as a numerical example.
https://amme.journals.ekb.eg/article_56805_afc8d0dd0cf13282fbbfad78de9ace59.pdf
1986-05-01
141
152
10.21608/amme.1986.56805
M.
Hedaya
1
Lecturer, Department of Design and Production Engineering, Faculty of Engineering, Ain Shams University, Cairo, Egypt.
AUTHOR
ORIGINAL_ARTICLE
VIBRATION ANALYSIS OF WANKEL ENGINE
The studies for decreasing the generated vibrations of Internal Combustion Engines are focused mainly on reciprocating engines, because of their wide usage. But there are little studies interested in the vibrtations of rotary Wankel engine.The main objective of this research is focused to:1. Develop a theoretical model of small NSU-Wankel engine for predicting the resultant shackingforces and moments.2. Study the characteristics of the induced vibrations during operation. Experimental investigation of the generated vibrations is used to assure the final results that are obtained from the theoretical analysis.
https://amme.journals.ekb.eg/article_56807_7b1164156d4d407bdd332e8c23a7fd25.pdf
1986-05-01
153
162
10.21608/amme.1986.56807
A.
Omar
1
Department of Design and Production Engineering, Faculty of Engineering, Ain Shams University, Cairo, Egypt.
AUTHOR
N.
Yasin
2
Technical Institute, Karkuk, Iraq.
AUTHOR
ORIGINAL_ARTICLE
VIBRATIONAL BEHAVIOR OF CRACKED JEFFCOTT ROTORS
A simplified mathematical model has been developed based on Jeffcott rotor to investigate the dynamic behavior of cracked shaft. Analysis has indicated the existance of unstable zones of operation at the vicinity of which rotor response is largely magnified. In general rotor response due to unbalance forces contain vibrations at 1/rev and 2/rev components while gravity excited vibration is characterized by 3/rev harmonics as well. The measured response curve of the rotor shows an increased shaft deflection at all speeds. Also a subcritical peak is detected. Comparing the analytical results with experimental measurements indicates that the mathematical model is very realistic.
https://amme.journals.ekb.eg/article_56809_b79e1c99c828a41f4f66a8bcceb2c970.pdf
1986-05-01
163
172
10.21608/amme.1986.56809
S.
Hassan
1
Cairo University, Faculty of Engineering.
AUTHOR
M.
Abouzaid
2
Kuwait Institute of Technology.
AUTHOR
ORIGINAL_ARTICLE
EFFECT OF PARTIAL ROTOR-TO-STATOR RUB ON SHAFT VIBRATION
The effect of partial rotor-to-stator rubbing is studied both experimentally and analytically. The measured vibration signalis distorted showing a flattenned portion of the waveform.' Spectral analysis indicated that light rubbing induced vibration is characterized by harmonics at frequencies equal to 1/rev., 2/rev. and 3/rev. Severe rubbing is identified by a spectrum containing subharmonics at 1/3, 2/3 of the rotational frequency. The synchronous component is generally attenuated as a result of rubbing introduced friction. Because of the stiffening effect of rubbing on the rotor, the resonance frequency is further delayed. The results obtained analytically show good qualitative agreement with the experimentally obtained ones.
https://amme.journals.ekb.eg/article_56812_9cd4d726767a4037da81fc36f579d50d.pdf
1986-05-01
173
182
10.21608/amme.1986.56812
S.
Hassan
1
Cairo University - Faculty of engineering,
AUTHOR
M.
Haddara
2
Kuwait institute of technology.
AUTHOR
M.
Abouzaid
3
Kuwait institute of technology.
AUTHOR
ORIGINAL_ARTICLE
A PARAMETRIC STUDY OF THE SIX-BAR QUICK RETURN MECHANISM
This paper deals with a computer aided design analysis of the six—bar quick return mechanism. The different dimensionless geometrical parameters and their effects on the kinematical characteristics of the mechanism are theoretically investigated. Compact design charts for velocitytacceleration and bearing reactions are presented and which provide the designer with optimal selections of link dimensions.
https://amme.journals.ekb.eg/article_56816_038c9a61db33e6e85f4c62456f11c9cf.pdf
1986-05-01
183
191
10.21608/amme.1986.56816
Quick return mechanism
Computer Aided Design
Kinematic
bearing reactions
M.
SHEBL
1
Assistant Prof.,Mechanical Design Dept.,Faculty of Engineering and Technology,Helwan University, Cairo, Egypt.
AUTHOR
Y.
YOUNS
2
Assistant Prof.,Mechanical Design Dept.,Faculty of Engineering and Technology,Helwan University, Cairo, Egypt.
AUTHOR
ORIGINAL_ARTICLE
SINGULAR PERTURBATIONS AND AIRCRAFT LONGITUDINAL DYNAMICS
The singular perturbations method is used to find a simplified solution of the longitudinal aircraft dynamics. The variables are devided into slow and fast. Then the steady state fast variables are used as input to the slow subsystem. The obtained simplified solution of the short period mode is the same as previously known solution of this mode. The obtained solution of the phugoid mode is basically different from the well known appro-ximate solution of this mode. Calculations proved that the obtained appro-ximate solution is very near to the exact one.
https://amme.journals.ekb.eg/article_56820_44891dfeb90bd1f374e422e5e00aa8d8.pdf
1986-05-01
193
201
10.21608/amme.1986.56820
I.
MANSOUR
1
AERONAUTICAL DEPARTMENT, M.T.C.,CAIRO,MEMBIR AIAA.
AUTHOR
M.
KATARY
2
AERONAUTICAL DEPARTMENT, M.T.C.,CAIRO.
AUTHOR
ORIGINAL_ARTICLE
ON THE APPLICATION OPOSCILLOGYRD IN INERTIAL NAVIGATION SYSTEMS
The trend of development of gyroscopes used in Inertial Navigation and Guidance systems, led to the adaptation of vibrating gyros to fulfil the basic requirements on such systems specially for military applications in aircraft and guided missiles. The oscillogyro is a new type of vibrating gyroscopes suitable for stabilizing inertial platforms. It is characterized by its simplicity, reliability and low cost of production. In this work, the application of oscillogyro in inertial navigation systems (INS) is introduced. After a short description of the oscillogyro as a two axes rate or displacement gyro, the mass- unbalance error is analyzed. The propagation of such error into an INS with single-axis vertical indicating platform, is investigated. The results of analysis show quite satisfactory performance and promising future for the application of oscillogyro in a wide range of INS and guidance systems.
https://amme.journals.ekb.eg/article_56845_543a57f632bb26d4c063eaf64e97294d.pdf
1986-05-01
203
214
10.21608/amme.1986.56845
A.
ABD EL-MOHSEN
1
Department of Mechanics and Elasticity, M.T.C. Cairo, Egypt.
AUTHOR
R.
BOUSHRA
2
Department of A/C El. & Spec. Equipment and Armament, M.T.C., Cairo. Egypt.
AUTHOR
ORIGINAL_ARTICLE
SUGGESTED MODIFICATIONS OF MERCHANT FORMULA FOR THE CALCULATION OF FAILURE LOAD OF FRAMES
The problem of calculating the theoretical failure load (WF) of a structure with good accuracy compared with its actual failure load value is a very important task of study. Rankine and Merchant suggested aformula for obtaining the failure load of a complete structure by analogy from isolated strut case and this in fact is an approximate method. An isolated strut Of an elastic critical load (Wc), yield load (WL) and failure load (WF) similar to complete structure behaviour.The application of Merchant equation for porta] and pitched-roof frames Ieads to an overage error equal to + 29% when the failure load calculated compared with its experimental value. Two suggested equations may be estimated after elastic-plastic analysis have been made on three different series of frames tested before till failure in Cambridge University laboratories by Dr. J.C. Heyman. It should be noticed that for frames having the value of (WL/WC) less than 0.3, the failure load of frames may be obtained using suggested equation (1), and for frames having the value of (WL/WC) bigger than 0.3 , the failure load obtained using suggested equation (2). These two suggested equations were estimated after the interpretation of the theoretical and experimental results of the different groups of frames used in that study. Tables and curves were given for the comparison of using these two suggested equations with the experimental failure load. To shows how the calculated value is so better compared with Merchant formula results.
https://amme.journals.ekb.eg/article_56849_0fc7015b603c366688ef70c9c6e56d0d.pdf
1986-05-01
43
53
10.21608/amme.1986.56849
Mohamed
Mahrous
1
COl.Dr., Military Technical College , Structural Engineering Department.
AUTHOR
ORIGINAL_ARTICLE
EFFECT OF SHEAR DEFORMATIONS ON THE BENDING OF MODERATELY THICK PLATES
The Bergan and Wang approach for the shear inclusion in plate deformation has led to an energy expression which is a function of the only lateral deflection. The corresponding Euler equation has been deduced and applied to a simply supported square plate with sinusoidal, uniform and concentrated loads. Numerical calculations have been made for different thickness to span ratios and the results agree well with those of other investigators.
https://amme.journals.ekb.eg/article_56850_bec767bb8e1773aae7c37d4c8f77bf69.pdf
1986-05-01
55
63
10.21608/amme.1986.56850
HAMED
ABDALLA
1
Lt. Col. Dr., Chair of Rockets, Military Technical College, Cairo, Egypt.
AUTHOR
KAMAL
HASSAN
2
Dr. Eng., Investigator, Ministry of Higher Education, Cairo, Egypt.
AUTHOR
ORIGINAL_ARTICLE
CREEP BUCKLING OF CYLINDERICAL THIN PANELS
A metaod of analysis is presented for circular cylinderical panels under external loads and steady creep deformations. The analysis are valid for small and moderately large displacements. Initial imperfections are included. The case of simply supported cylinderical panels under external axial compressive load is investigated in detail. The buckling and post buckling behavior of cylinderical panels is described first, the analysis is based on Von Karman Donnell general equations for cylinderical shells. Using the Norton's secondary creep law, the deformation rate and creep buckling were described in order to predict the critical creep time of cylinderical panels under steady creep conditions.
https://amme.journals.ekb.eg/article_56851_99104ed2a161a20ffc68f3f2603b6aa3.pdf
1986-05-01
65
72
10.21608/amme.1986.56851
Magdy
Adib
1
Col. Eng., Egypt Air Academy.
AUTHOR
H.
Ashour
2
Dr., Egypt Air Academy.
AUTHOR
ORIGINAL_ARTICLE
A SIMPLE METHOD FOR DETERMINATION OF THE FRACTURE-MECHANICS GEOMETRIC PARAMETER KI
The method discussed in this paper describes a three parameter method of analysis for accurate detrmination of the stress intensity factor (SIF) using the crack tip stress field information given by photoelasticity. The sole objective is, in fact, to determaine a specific parameter or set of parameters which when used with the experimental results provide, the best match between the experimental and analytical results. A new three parameter method is using information from only one fringe loop is introduced which followes the method developed by Fattah, flj for determination of mixed mode stress intensity factors (K1 and KII). The three parameter used in the present method are, σox= αK/√2πa, which acts parallel to the direction of the crack extension, the stress intensity factor (KI) and a parameter β which is a term added to the Westergaard stress function to provide one more degree of freedom. A new simple formula for β determination has been introduced in this analysis to take care of fare field stresses, finite dimension, crack tilt angle and curvature effects. A method of solution based on measurements rm , θm and r at θ= π/2 from only one fringe loop is given. A systematic experimental study on finite CCT, SEN and DEN plates has been carried out for various value of λ(=-2a/W) with fringe data collected from near the crack tip. The results obtained for Dobeckote-505 show good agreement with the analtical results.
https://amme.journals.ekb.eg/article_56864_1b48f2ae6fae85d3aba7f4e2b74e1462.pdf
1986-05-01
73
81
10.21608/amme.1986.56864
A.
Fattah
1
Lecturer, Department of Design and Production Engineering, Faculty of Engineering, Mansoura University, El_Mansoura, Egypt.
AUTHOR
ORIGINAL_ARTICLE
ANALYSIS OF ELASTIC-PLASTIC DEFORMATIONS OF STRAIGHT WINGS
The paper presents a computer analysis for the determination of the wing twist. It is suitable for the calculation of the elastic and plastic angle of twist of straight wings. The wing twisting is assumed due to the action of aerodynamic and mass forces. The computer program is applied to L-29 advanced jet trainer for the calculation of wing twist.
https://amme.journals.ekb.eg/article_56989_b35ee1282dee87b3da01ba5a9aa8251b.pdf
1986-05-01
83
92
10.21608/amme.1986.56989
M.
KATARY
1
Lt.Col.Dr., AERONAUTICAL DEPARTMENT,M.T.C.,CAIRO.
AUTHOR
I.
MANSOUR
2
Col. Dr., AERONAUTICAL DEPARTMENT,M.T.C.,CAIRO,MEMBER AIAA.
AUTHOR
M.
RASHED
3
Prof. Dr., PROFESSOR EMERITUS,AERONAUTICAL DEPARTMENT,FACULTY OF ENGINEERING,CAIRO UNIVERSITY,GIZA.
AUTHOR
ORIGINAL_ARTICLE
RECENT ADVANCES IN THE DYNAMIC ANALYSIS OF LIQUID FILLED. TANKS
Liquid storage tanks are important components of many civilian and military facilitiea. They have a vital role for storage of water and other liquids for use in military bases, industrial companies, nuclear reactor installations and water supply facilities. The dynamic behavior of these tanks under different forms of loading such as blasts, winds and earthquakes is of. intereat. The influence of fuel tanks in rockets on the flight control system is another matter of concern. Although the behavior of tanks under dynamic loadings has received considerable attention during the past three decades in civil, mechanical and aerospace engineering, recent results are not readily available in a comprehensive form suitable for design. The aim of the present paper isto address recent advances in the dynamic analysis of tanks, to bridge the gap between academic and practical applications, and to present a comprehensive review of the subject which makes iL more under-standable and useful to researchers and to practicing engineers. A review of current design practice is presented and recommended design provisions are described.
https://amme.journals.ekb.eg/article_56990_b5a93a42c81a0a4d021d98f183248c69.pdf
1986-05-01
93
102
10.21608/amme.1986.56990
MEDHAT
HAROUN
1
Associate .Professor , Civil Engineering Department, University of California, Irvine, California 92717, U.S.A. Currently, Visiting Professor, FacUlty of Engineering, Cairo UniverSity, Giza, Egypt.
AUTHOR
ORIGINAL_ARTICLE
SQUEAL NOISE IN DISC BRAKES : A THEORETICAL MODEL
The paper examines in detail four separate models of disc brake squeal. The mathematics of each model are produced together with the underlying mechanism of squeal. The four models are compared one with another to demonstrate their essential features. Examinations of these models showed that two simplifi-ed models can be applied to the disc brake system. These are the cantilever-disc and pin disc models. A double pin-disc model is developed and some stability results are reported
https://amme.journals.ekb.eg/article_56991_6133b1b5fcb00693e18b94c188827740.pdf
1986-05-01
27
40
10.21608/amme.1986.56991
M.
EL-SHERBINY
1
Professor., Dept. of Mech. Design and Production Faculty of Engineering, Cairo University.
AUTHOR
F.
SALEM
2
Associate Professor., Dept. of Mech. Design and Production Faculty of Engineering, Cairo University.
AUTHOR
ORIGINAL_ARTICLE
PERFORMANCE OF ASBESTOS-FILLED RESIN COMPOSITES PART I: MECHANICAL PROPERTIES
Brake linings for modern saloon cars are formulated from asbestos fibres as a reinforcement, phynolic formaldehyde resin as a binder, and different fillers to modify the different properties of the linings. To study the effect of every constituent on the mechanical properties, different formulations were produced with different asbestos-resin content ratio and the mechanical proper-ties, mainly, the ultimate tensile strength, impact strength, hardness, and the compressive strength were measured. Definite dependency of the mechanical properties of such formulations on the asbestos-resin weight ratio was noticed.
https://amme.journals.ekb.eg/article_56992_3630d757541226cd615982b5de4ef275.pdf
1986-05-01
111
119
10.21608/amme.1986.56992
A.
MOUSTAFA
1
Associate Professor, Mech. Design Dept., Faculty of Engineering, Cairo University.
AUTHOR
A.
KIIATTAB
2
Assistant Professor, Mech. Design Dept., Faculty of Engineering, Cairo University.
AUTHOR
I.
QASHQOUSH
3
Post graduate student, Mech. Design Dept., Faculty of Engineering, Cairo University.
AUTHOR
ORIGINAL_ARTICLE
PERFORMANCE OF ASBESTOS-FILLED RESIN COMPOSITES PART II: TRIBOLOGICAL PROPERTIES
Automotive brake linings used nowadays are a complex composite of organic resin binder, asbestos fiber reinforcement and friction modifying fillers. This paper investigate the dependency of the tribological properties, mainly, the co-efficient of friction, the wear rate, and the fade temperature on the constituents used to formulate the linings. Seven formulations were produced with different asbestos/resin content ratio. The tribological properties were measured. The drag dynamometer results showed that the fade temperature and the. wear rate increases as the asbestos content increases. The coefficient of friction of low asbestos content varies initially from 0.2 to 0.25 but it decreases rapidly to 0.1. For high asbestos contents, the coefficient of friction was appeared to be erratic.
https://amme.journals.ekb.eg/article_56994_301013936ff17df7c54c1b8a9cd45399.pdf
1986-05-01
121
132
10.21608/amme.1986.56994
A.
MOUSTAFA
1
Associate Professor, Mech. Design Dept. Faculty of Engineering, Cairo University.
AUTHOR
A.
KHATTAB
2
Assistant Professor, Mech. Design Dept. Faculty of Engineering, Cairo University.
AUTHOR
I.
QASHQUSH
3
Post graduate student, Mech. Design Dept. Faculty of Engineering, Cairo University.
AUTHOR
ORIGINAL_ARTICLE
QUALITATIVE CONNECTION BETWEEN SOLID' PARTICLE EROSION AND MECHANICAL PROPERTIES OF ELASTOMERS
Elastomers have good erosion resistance. They are used in coating materials sucentible to solid particle erosion, such as fibre glass reinforced polymers. Erosion parameters of the attacking solid particles affecting erosion resistance of elastomers are reviewed. A model connecting erosion resistance and mechanical properties of elastomers is suggeted and experimentaly verified. A constant is proposed in the model and it explained in light of parameters of the erosive particles. The model shows that selection of an elastomer with high erosion resistance is based on selection of an elastomer having a big product of fracture strength and strain. Further work is suggested on study of effect of thick-ness of the elastomer coat on erosion resistance of the coated material.
https://amme.journals.ekb.eg/article_56995_5e39db797bf2d3fb874a5bc876cc362a.pdf
1986-05-01
133
143
10.21608/amme.1986.56995
F.
BASSILI
1
Lecturer, University of Suez Canal, Faculty of engineering for Petrol and Mining, Suez, Egypt.
AUTHOR
ORIGINAL_ARTICLE
A STUDY ON THE EFFECT OF SOME CLIMATIC FACTORS ON OIL CONSUMPTION RATES IN A RECIPROCATING DIESEL ENGINE.
The paper reports the results of an experimental investi-gation on the effect of some climatic factors on oil consumption rates. Worn compression rings having a profile of super ellipse, high cooling temperatures and contaminated lubricants were considered in the study. The testing program was achieved on an EMSON AVI single cylinder diesel engine with a complete set of control and measuring devices. Different wear indices for the compression rings were investigated over the mechanicl and running conditions range of the tested engine. Three oils with different iron and dust contents were tested. Optimal oil consumption rates have been observed for worn ring shapes and which can be proposed for actual automotive engines. The interaction between oil contamination ratios and cooling temperature have been examined and reported.
https://amme.journals.ekb.eg/article_56999_7ebcab5f47f01a6edd4153fac8756169.pdf
1986-05-01
145
154
10.21608/amme.1986.56999
Y.
YOUNES
1
Assistant prof., Mech. Design Dept., Faculty of Eng., Helwan Univ., Mataria, Cairo.
AUTHOR
A.
SCHARARA
2
Associate Professor, Automotive Dept., Faculty of Eng., Mataria, Cairo.
AUTHOR
A.
ABOUEL-YAZID
3
Assistant Lecturer, Automotive Dept., Faculty of Eng., Mataria, Cairo.
AUTHOR
ORIGINAL_ARTICLE
PERFORMANCE CHARACTERISTICS OF THE RICE MILLING MACHINE
The objective of this work is to study the effect of some operational factors on the performance of the rice milling machine. These factors are, feed rate, moisture content of paddy rice (raw material) and whitening roll speed on the power consumed, required torque, grain damage and unit energy per Kg of white ric, (product) in the milling process. The samples of paddy rice Japanes variety used in the experimental work. From the experimental results the following conclusions are obtained:1. Feed rate of (6.5 kg/min) is found to be an optimum value at M.C.. 13% and 450 R.P.M.2. As the M.C. (moisture content) of paddy rice increases the grain damage decreases at all roller speeds.3. As the feed rate increases the grain damage decreases until it reaches an optimum value and then increases.
https://amme.journals.ekb.eg/article_57000_27b3b83dca250d25ac48a53e783012c2.pdf
1986-05-01
155
164
10.21608/amme.1986.57000
A.
ABOU EL -EINENE
1
Dept. of Production Eng. and Machine Design, Faculty of Eng. and Tech. Menoufia Univ., Shebin EL-Kom, Egypt.
AUTHOR
M.
SHARAF
2
Dept. of Production Eng. and Machine Design, Faculty of Eng. and Tech. Menoufia Univ., Shebin EL-Kom, Egypt.
AUTHOR
A.
KHORSHED
3
Dept. of Production Eng. and Machine Design, Faculty of Eng. and Tech. Menoufia Univ., Shebin EL-Kom, Egypt.
AUTHOR
ORIGINAL_ARTICLE
A DESIGN ALGORITHM TO CALCULATE THE STATIC STIFFNESS OF' NUM-BOLTED JOINT. Part. I Joint Stiffness Analysis
The multi-bolted joint is commenly used in various machine design problems. In order to predict the static behaviour of the machine tool structures, it is necessary to know the stiffness of the joints between their components.This paper is concerned with the establishment of mathematic-al models which enable to analysis the static behaviour of the multi-bolted joints in machine tools. Several assumptions have been taken into consideration to simplify the proposed mathematical models.
https://amme.journals.ekb.eg/article_57005_c06f504fb11004839e1fe7484f92563e.pdf
1986-05-01
165
177
10.21608/amme.1986.57005
GABER
SHEHA
1
Dr. Eng., Lecturer, Dept. of Production Eng. and Design , Faculty of Eng. and Tech., Menoufia University, Shebin El-Kom. Egypt.
AUTHOR
ORIGINAL_ARTICLE
A DESIGN ALGORITHM TO CALCULATE THE STATIC ST7FPNESS OP THE MULTI - BOLTED JOINT. PART II: JOITT DESIGN ALGORITHM .
To day designers of the machine tools requires acceptable and simple methods or tools which enable to achieve their works in minimum time and less effort. Therefore, this work is concerned with establishment Of a design algorithms to calculate the value of the static stiffness of a fixed joint based on the multi-bolted joint. This model has been developed in the first part of this paper. Based on the elements of this model will be deciding the proper algorithm which can be used to calculate the static stiffness values.The comparison of calculated and experimental results is also given.The proposed design algorithm and its computer program are now available to the designers.
https://amme.journals.ekb.eg/article_57012_bf4470d23b0a1beebbbb3eaf32bbb836.pdf
1986-05-01
179
188
10.21608/amme.1986.57012
Gaber
SHEHA
1
Dr. Eng., Lecturer Dept. of production Eng. and Design, Faculty of Eng. and Tech., Menoufia University, Shebin El-Kom,EGYPT.
AUTHOR
ORIGINAL_ARTICLE
SCALE EFFECTS ON LIMITED CAVITATION PRODUCED BY VIBRATION OF THE WETTED SURFACE OF CYLINDER LINERS
The processes of cavitation erosion in the space within the cylinder jacket of Diesel engines, which is the principal cause of failure of the outer wetted surface of cylinder liners, can be suppressed by avoiding the appearance of cavitation. This can be achieved if reliable information existed about the scale effects on the inception of cavitation which are an important consideration in the prediction of inception in a design process. Unfortunately there is insufficient information available at present to help the engine designer. Therefore, the purpose of this paper is two-fold. First, new experimental data are presented which show the effects of the vibration frequency, water distance, and water temperature and pressure on the inception of cavitation. Second, a model for the inception of cavitation is presented. Cavitation inception data are presented and discussed for a vibratory setup. The vibratory setup was designed to simulate the flow on the wetted surface of a liner. Measurements of inception were obtained visually through a transparent beaker containing tap weter. The effects of vibration frequency, water depth, static pressure of water and water temperature on the inception of cavitation were investigated. The results showed that the cavitation inception vibration amplitude decreased with increasing the vibration frequency and the temperature of water. In addition, the cavitation inception vibration amplitude increased as the depth of water increased. The results were compared with the model and a good agreement was observed. In the light of these results the designer should design his engine with cylinder liner vibration amplitude less than the inception vibration amplitude to operate his engine free of cavitation and therefore to avoid damage due to Cavitation.
https://amme.journals.ekb.eg/article_57021_269dd728421e4ef7f0b78aa6cb61bea1.pdf
1986-05-01
189
203
10.21608/amme.1986.57021
Sobeih
SeliM
1
Associate Professor, Mechanical Power Engineering Department, Faculty of Engineering and Technology, Menoufia University, Shiben El-Kom, EGYPT.
AUTHOR
ORIGINAL_ARTICLE
BEHAVIOUR OF FATIGUE CRACK PROPAGATION IN Cr - V SPUR GEAR MODEL .
On single edge bend (SEB) specimens and spur gear models the fatigue crack propagtion rate at very low stress intnsity factor (SIF) was measured . The SIF for spur gear model was obtained by compliance measurements. The following expression which involves the threshold value of SIF was used to analyse the results .da/dN= A [{ Ka/(1-R)r}β{Kat/(1-R)r}β]
The present results beside it adds to the experimental evidence supporting the independence of growth rate on geometry of tested body, it extends the conclusion to cover the uninvistigated region at very low SIF.
https://amme.journals.ekb.eg/article_57031_ca1e874b125ab20b23094cd94059bde1.pdf
1986-05-01
205
216
10.21608/amme.1986.57031
MAHER
EL DESSOUKY
1
DR. ENG., CHAIR OF MACHINE DESIGN - MTC, CAIRO .
AUTHOR
ORIGINAL_ARTICLE
FRICTIONAL BEHAVIOUR OF SURFACES COMPOSED OF MULTI-LAYERS
This work presents an experimental investigation into the fri-ctional behaviour of surfaces composed of multi-layers. The effect of using single or multi-metalic layers adhered to a hard or soft substrate on frictional behaviour has been fully analyzed under dry orlubricated situations. Asteel substrate covered by copper layer, or electrically coated by chromium, nickel, or copper, and brass substrate covered by aluminium layers were used. The coefficient of friction couldbe recorded under a sliding speed ranging from 0.26 m/s to 2,54 m/s and a load ranged up to 540 N. It could be concluded that the existance of layers affect the frictional behaviour in a manner dependent on layer material, layer thickness, the applied load and operating speed.
https://amme.journals.ekb.eg/article_57032_13ed1e114c210bb656f4f913f1da9bf9.pdf
1986-05-01
217
227
10.21608/amme.1986.57032
M.
MOKHTER
1
Prof.,Mech.Design & Prod.Dept.,Cairo University, Egypt.
AUTHOR
S.
KHALIFA
2
Colonel Dr.Eng.,Machine Design Dept.Military Technical College, Egypt.
AUTHOR
F.
EL NAGGAR
3
Colonel, Military Engineering Dept., Egypt.
AUTHOR
ORIGINAL_ARTICLE
OPTIMAL DESIGN OF HYDROSTATIC BEARINGS
Optimum hydrostatic circular rotating bearing design is the objective of the designer. Most of the previous designs concerned with the optimization of single objective function such as minimization of power loss or maximization of static and dynamic stiffness. An alogorithm for solving bicriteria programming problems has been constructed and used successfully for solving the problem of optimal design of hydrostatic thrust bearing under rotation. A significant results has been obtained.
https://amme.journals.ekb.eg/article_57035_9d13657f527b995d3b654482bf53ca95.pdf
1986-05-01
229
237
10.21608/amme.1986.57035
M.
Nasser
1
Dept. of Production Engineering & Machine Design, Faculty of Engineering & Technology, Menoufia University, Shebin El-Kom, EGYPT.
AUTHOR
A.
El-Sawy
2
Dept. of Mathematics, Faculty of Engineering & Technology, Menoufia University, Shebin El-Kom, EGYPT.
AUTHOR
ORIGINAL_ARTICLE
APPLICATIONS OF SINGLE PHASE AND MIXTURE FLOW INTO LUBRICATION OF MILLING MACHINE TABLE
Comparative cutting tests have been carried out on a horizontal milling machine, having the worktable fitted, in turn, with pressurized oil "single phaseflow"bearings,pressurized mixture flow, and a conventional lub-ricational system. Special table and saddle for that machine were designed and manufactured to be capable for applying all methods of lubrication. Awide range of depth of cuts and feed rates were used. Both surface roughness and vibrational parameters were measured. The use of pressurized oil and mix- ture flow bearings slideways increase the machine stability and produced more fine surface roughness than conventional lubrication slideways.
https://amme.journals.ekb.eg/article_57038_286a24400b801b3b0d5759320c453581.pdf
1986-05-01
239
246
10.21608/amme.1986.57038
E.
Salem
1
Professor, Mech. Engg. Dept., Faculty of Engg. Alexandria, EGYPT.
AUTHOR
S.
Serage
2
Associate Professor, Production Engg. & Mach. Design Dept.,Faculty of Engg.&Technology, Menoufia University, Shebin El-Kom, EGYPT.
AUTHOR
M.
Nasser
3
Assistant Professor, Production Engg. & Mach. Design Dept.,Faculty of Engg.&Technology, Menoufia University, Shebin El-Kom, EGYPT.
AUTHOR
A.
Mansour
4
Graduate Student, Production Engg. & Mach. Design Dept.,Faculty of Engg.&Technology, Menoufia University, Shebin El-Kom, EGYPT.
AUTHOR
ORIGINAL_ARTICLE
A STUDY OF TRUCKS ENGINE FAILURE RELATED TO ENVIRONMENTAL CONDITIONS
On operating new trucks in one of the areas of the Egyptian western desert, unexpected fast engine failure occured. Although the technical maintenance to these trucks, was regularly done, the engine failure took place after covering 26000 Km only. In the meantime, no similar failures of trucks operating in other zones have been reported. Therefore, the main reason that led to the engine failure was attributed to the environmental conditions characterised by high dust concentration and relatively high temperature. After reviewing the air and cil filteration systems of the damaged engine and making the necessary inspection and measurements it could be said that the failure occured main-ly due to inefficient oil filteration. A new oil filter, designed by the manufacturer, and the old one have been tested by a special testing rig that has been designed and constructed by the author. Tests on the old and new filters showed that the new one has considerably better performance. In addition, a new engine having the redesigned oil filter has been tested on an engine dynamometer for 400 hcurs. During engine testing, a contaminat dust was added to the oil sump to simulate the actual working conditions, the test results showed no drop in oil pressure and no excessive engine noise which proved the suitability of redesigned oil filter.
https://amme.journals.ekb.eg/article_57039_f70af6be9294dfa107cef23a54296da0.pdf
1986-05-01
247
261
10.21608/amme.1986.57039
M.
Youssef
1
Col.M.Sc (Eng)., Leader of automobile department, Lecturer of Automobile theory, Technical Institute of Armed Forces, Cairo, Egypt.
AUTHOR
ORIGINAL_ARTICLE
ENERGY LOSSES OF SOFT METAL FILMS ON STEEL IN ROLLING FRICTION
For a sphere rolling freely on a flat elastic surface,energy loss is usually refered to the elastic hysteresis lossee. The value of the elastic hysteresis loss coefficient is constant and function of the elastic properties of the contacting materials.In the present work,the experimental results showed that soft lead films behave elastically under the application of high values of normal force.It is also shown that the elastic hys-teresis loss coefficient is,not only a function of the elastic properties of the contacting material,but also function of the normal load.The relationship between the value of the elastic hysteresis loss coefficient, for lead and silver films on heel substrate,and the normal force is presented together with the measured value for the uncoated steel surface which took a constant value.
https://amme.journals.ekb.eg/article_57051_25250f7f9361980c143a8080589a3318.pdf
1986-05-01
263
277
10.21608/amme.1986.57051
T.
El—Shafei
1
Lecturer, Military Technical College, Cairo, Egypt.
AUTHOR
ORIGINAL_ARTICLE
AN EXPERIMENTAL STUDY OF THE FRICTION TORQUE OF THRUST BEARINGS COVERED BY SOFT METAL FILMS WHEN OPERATIAG TN VACUUM
The life of bearings is mainly affected by the efficiency of its lubrioation,for bearings operating under severe conditions such as high vacuum and temperature,conventional lubrication presents many problems. Perwenent thin soft metal-films give a solution to this problem. A rig was built to measure the friction torque for ball thrust bearings operating in vacuum. This paper describes an investigation of the friction toraue of thrust bearings covered by thin lead and silver films operating in vacuum. The effeat of normal load and ball-track conformity. have been studied,It is shown that the friction torque for the uncoated bearings increases when operating in vacuum especially for high values of ball-track conformity,lt is also shown that the coating decreaaes the friction torque for all values of ball-track conformity and the value of the friction toroue for these bearings does not increase when operating in vaouum.
https://amme.journals.ekb.eg/article_57053_5b8796beac4d7e79710cdd49282a6422.pdf
1986-05-01
279
289
10.21608/amme.1986.57053
T.
EL-SHAPEI
1
Military Technical college,Gairo, EGYPTt.
AUTHOR
ORIGINAL_ARTICLE
A PROPOSED PARKING DEVICE FOR MOTOR VEHICLES
A tentative construction has been herein proposed to develop a parking device to be attached to motor vehicles. the device is simple in design, ma-nufactured to suite various types of aukimotives & based on a special gear train powered by 12V D.C. motor. The device can be controlled by the driver to park safely in a minimum manoeuvring distance, also can be used for car jacking and trailing in case of emergency. Based on a study of 3-Wheeled vehicle dynamics, a formula has been derived to estimate proper steering power and to put some bases for further opti-mization processes.
https://amme.journals.ekb.eg/article_57055_11b8070b58dc9474d2082f071dcb3362.pdf
1986-05-01
291
298
10.21608/amme.1986.57055
Parking
device
Lifting
Mechanism
Dynamics
design
M.
RADWAN
1
Associate Professor., Department of Mechanical Design & Production, Faculty of Engineering, Cairo University.
AUTHOR
M.
MOKHTAR
2
Professor., Department of Mechanical Design & Production, Faculty of Engineering, Cairo University.
AUTHOR
S.
EL-MAHDY
3
Graduate Student., Department of Mechanical Design & Production, Faculty of Engineering, Cairo University.
AUTHOR
ORIGINAL_ARTICLE
APPLICATION OF THE METHODS OF SELECTION OF GEAR BOX RATIOS TO PASSENGER CARS
Selection of ratios in mechanical transmission of motor vehicles can be done according to various mathematical prog-ressions such as : arithmatic, harmonic and geometric with constant and increasing roots. In a paper presented by the same authors, a comparison of the methods of selecting the gear ratios has been made. This was done by calculating the wasted power due to their stepped tractive effort - speed characteristics relative to the ideal one with continuous power transmission. it has been concluded that the gemetric progression would give the least wasted power. This conclusion was based on calcula-tions considering the data of only one Jeep car. The objective of this paper is to prove the validity of the above mentioned conclusion. In this regard, same method of comparison was applied to 14 small and medium class dif-ferent passenger cars having engines of swept volume between 0,9 and 1.6 litre.
https://amme.journals.ekb.eg/article_57056_918baeb3d00684e82a8d5097d8a3d038.pdf
1986-05-01
299
314
10.21608/amme.1986.57056
SAYED
SHAABAN
1
Col Dr., Chief of Dept. of Motor Vehicles, Military Technical College, Cairo, Egypt.
AUTHOR
SAID
HASSAN
2
COL DR., Lecturer at the Dept. of Motor Vehicles, Military Technical College, Cairo, Egypt.
AUTHOR
ORIGINAL_ARTICLE
STRUCTURE AND PROPERTIES OF SEVERAL STEELS PRODUCED 'BY CONTROLLED SOLIDIFICATION PROCESSES
Controlled solidification has considered areat attention in the last decade with the engineering aim of developing structures with improved properties and performance characteristics. Fundamental and applied research work in this field has led to the finding out of new processes which produce improved or novel structures. Steady state directional solidification (DS) MI stir or rheo-casting (RC) are two examples of these processes, which have been applied in this work on several types of steel. The improvements gained in structure, segregation and mechanical properties, due to the application of these processes compared to the conventional casting (CC) are briefly presented in this paper refering to author's work. In DS, plain carbon, low alloyed Mn-Ni, higly alloyed Mn, Mn-Ni and Cr and low carbon steels have been considered. Generally, the structure of these steels has dendrites aligned in the heat flow direction. A rod-like dendrite shape is obtained at high G/R values (G is the temperature gradient and R is the growth rate) while secondary and tertiary dendrite arms appear as G/R values decreases. Measurements of dendrite arm spacings show that they are functions of R-nG-m. Such relationship is useful in controlling the structure and hence the properties. Mechanical testing of some castings indicates high tensile properties for the rod-like DS structure which is even higher than that of the forged structure for the same material. In RC, a novel structure with nearly spherical primary particles is obtained for the Carbon and stainless steels used.
https://amme.journals.ekb.eg/article_57060_53223d219d257f231a6dcd7a7a357a76.pdf
1986-05-01
111
134
10.21608/amme.1986.57060
MOHAMED
TAHA
1
Professor, Department of Mechanical Design and Production Engineering, Ain Shams University, Abaseia, Cairo - EGYPT.
AUTHOR
ORIGINAL_ARTICLE
EFFECT OF Mg CONTENT ON PENETRATION RESISTANCE OF Al- Mg ARMOUR PLATES
A series of Al-Mg armour plates were cast in a metallic mold with Mg content varying from l% to 5% Mg. The effect of Mg content on the mechanical properties and microstructure was investigated. Tensile,Impact toughness,and Hardness tests were carried out on specimens machined from the 35 mm thickness cast armour plates. Penetration resistance tests were carried out on 200 x 200 x 32 mm plates using 7.62 x 39 mm projectiles. Energy consumed during penetration was evaluat-ed and taken as a measure of penetration resistance.The following relationship between penetration resistance and Mg content was deduced using the obtained results :P.R. = 1366 + 58 (Mg % ) .where P.R. = Penetration Resistance ( Joules ).
https://amme.journals.ekb.eg/article_57064_5e27afa1cf73510453ac46d92c844e94.pdf
1986-05-01
135
145
10.21608/amme.1986.57064
M.
Sultan
1
Department of Materials and Processing, Military Technical College, Cairo, EGYPT.
AUTHOR
B.
Elsarnagawy
2
Department of Materials and Processing, Military Technical College, Cairo, EGYPT.
AUTHOR
A.
Elsebaie
3
Helwan Company For Non-Ferrous Industries, Cairo, EGYPT.
AUTHOR
A.
Ghani
4
Department of Materials and Processing, Military Technical College, Cairo, EGYPT.
AUTHOR
ORIGINAL_ARTICLE
HEAT TREATMENT OF LIQUID PHASE SINTRED DUPLEX POWDER PREFORMS
The purpose of the present work is to investigate the effect of heat treatment on duplex powder preforms with liquid phase sintering For such a study, 4607 alloy steel powder with the separate addition of some clifferent brazing alloy powders were prepared as well as NC 100.24 iron powder. Some cylindrical duplex preform samples were produced by suitable compaction and sintering for different times. NC 100.24 iron powder was invaribly located in the core,whilst the sheath material was one of the alloy steel prepared with and without the additives. The specimens were then properly heat treated to record its effect on hardness values. Crushing tests and microhardness tests were performed across the material transition zone. The results were discussed in terms of micro—structures examination.
https://amme.journals.ekb.eg/article_57067_184a73f950c2605ce4af6ccfaa4ddc5c.pdf
1986-05-01
147
155
10.21608/amme.1986.57067
M.
Abd—Elatif
1
Mechanical Engineering Department,Al-Azhar University,Cairo,Egypt.
AUTHOR
M.
Hamouda
2
Mechanical Engineering Department,Al-Azhar University,Cairo,Egypt.
AUTHOR
G.
Said
3
Mechanical Engineering Department,Al-Azhar University,Cairo,Egypt.
AUTHOR
M.
Negm
4
Mechanical Engineering Department,Al-Azhar University,Cairo,Egypt.
AUTHOR
ORIGINAL_ARTICLE
CONTROL OF CONTINUOUS RHEOCASTING PROCESS USING HEAT FLOW MODEL
In the continuous rheocasting process, a semi-solid alloy is obtained from the exit port of the apparatus at a given rate and with a given fraction solid. This fraction solid is dependent on the corresponding temperature within the solid-liquid range which should be controlled accurately by the process parameters for a given rheocaster stirring chamber.For this purpose a heat flow model has been established for the continuous rheocasting of Bi-17wt%Sn alloy. The heat transfer calculations are based on the solution of the two-dimensional partial differential equations using a finite difference method. An excellent agreement between calculations and experimental results is found. Computations are carried out in order to find the influence of stirring chamber dimensions on the alloy exit temperature and therefore, the volume fraction solid. The influence of input metal temperature and metal flow rate on the exit temperature and volume fraction solid are also found.
https://amme.journals.ekb.eg/article_57072_2315d728fca3c932db287486aa2fd045.pdf
1986-05-01
157
170
10.21608/amme.1986.57072
Abdel-Wahed
Assar
1
Dept. of Mechanical Design and Production Engineering, Faculty of Engineering, Ain- Shams University, Abaseia, Cairo, Egypt.
AUTHOR
Nahed
El-Mahallawy
2
Dept. of Mechanical Design and Production Engineering, Faculty of Engineering, Ain- Shams University, Abaseia, Cairo, Egypt.
AUTHOR
Mohamed
Taha
3
Dept. of Mechanical Design and Production Engineering, Faculty of Engineering, Ain- Shams University, Abaseia, Cairo, Egypt.
AUTHOR
Ahmed
El-Sabbagh
4
Dept. of Mechanical Design and Production Engineering, Faculty of Engineering, Ain- Shams University, Abaseia, Cairo, Egypt.
AUTHOR
ORIGINAL_ARTICLE
IMPACT TOUGHNESS OP AUSTEMPERED DUCTILE CAST IRON
The influence of austempering temperature and time, as main austempering control parameters, on the impact toughness and microstructure of a ductile cast iron alloy having a carbon equivalent of 3.88 percent has been investigated. Two transformation temperatures were chosen at 270°C and 400°C such as to obtain microstructure falling within the zones of lower and upper bainite, respectively. Austempering time intervals ranging from 5 minutes to 5 hours were selected for each austempering temperature. Peak values of U-notch Charpy impact toughness of 7.55 and 17.23 Joule/cm² have been attained at time interval of 60 minutes for specimens austempered at 270°C and 400°C, respectively. The changes in mechanical properties with the transformation temperature and time has been observed to be directly related to the phase transformations in the micro-structure. The study of fracture surfaces of impact toughness samples revealed the great complexity of the crack propagation process in austempered ductile iron due to the nature of its structure.
https://amme.journals.ekb.eg/article_57076_941821fc11fd386113c680e8e0633b9c.pdf
1986-05-01
171
180
10.21608/amme.1986.57076
Austempered ductile iron
micro-structure
upper bainite
lower bainite
Mechanical Properties
H.
Abu-Elfotouh
1
Dept. of Metallurgy,Military Technical College,Cairo,Egypt.
AUTHOR
O.
Abu-Zeid
2
Dept. of Mech. Design and Prod.,Cairo University,Egypt.
AUTHOR
B.
Elsarnagawy
3
Dept. of Metallurgy,Military Technical College,Cairo,Egypt.
AUTHOR
A.
Eleiche
4
On leave to Dept. of Engineering,The American University in Cairo, Egypt.
AUTHOR
ORIGINAL_ARTICLE
SURFACE AND SUBSURFACE FEATURES OF WORN ALUMINIUM-SILICON BASE ALLOYS.
The worn surface of a modified aluminium-silicon eutectic alloy are examined in order to determine the nature of surface damages. Furthermore, an attempt is made to relate the surface features to the mechanism by which the wear particles are formed. Oblique sections of worn materials are used to examine the extent of subsurface changes through both microhardness measurements and metallography observation. The results indicate that both wear features and mechanism are different when the binary eutectic AL/Si alloys are compared to the modified materials.
https://amme.journals.ekb.eg/article_57080_867a35baf860f685e1bb0e8e089559ce.pdf
1986-05-01
181
188
10.21608/amme.1986.57080
S.
IBRAHIM
1
Met. Dept. Faculty of Pet & Mining Eng., Suez Canal University. Suez.
AUTHOR
M.
SAMI
2
Welding electrode Factory.
AUTHOR
ORIGINAL_ARTICLE
FACTORS AFFECTING SHRINKAGE CAVITY FORMATION IN GREY IRON CASTINGS
Shrinkage cavity formation in grey iron castings was investigated using, special mould arrangement allowing easy determination of the shrinkage. volume after solidification. The effect of melt chemistry was studied' by variation of carbon equivalent from 3.59% to 4.59% and determination of the corresponding change in shrinkage volume. The effect of silicon content in the melt for the same carbon equivalent CE is also tested to show the effect of silicon content on shrinkage amount. The relation between eutectic graphite content and the shrinkage volume in grey cast iron ingots was evaluated. Low shrinkage values were observed at high eutectic graphite contents. Effect of pouring temperature on the shrinkage volume was evaluated using five different pouring temperatures 1180 00,1200e, 1250 C°, 1285 C° and 1320 C° while keeping all other casting conditions constant. Shrinkage volume of grey cast iron was found to increase by increasing pouring temperature. The effect of mould rigidity on grey iron shrinkage was evaluated using different moulding materials. High shrinkage volumes were observed at low rigidity moulds. The control of phosphorous content in the melt was found to reduce the sensitivity of measured shrinkage volumes to variation of mould rigidity.
https://amme.journals.ekb.eg/article_57085_467b7bdaea4769a388dac594d8598917.pdf
1986-05-01
189
201
10.21608/amme.1986.57085
B.
El SARNAGAWY
1
Department of Materials and Processes, Military Technical College Cairo, Egypt.
AUTHOR
M.
SALLAM
2
Department of Materials and Processes, Military Technical College Cairo, Egypt.
AUTHOR
H.
MADI
3
Helwan Iron Foundries, Cairo, EGYPT.
AUTHOR
ORIGINAL_ARTICLE
ESTIMATING TECHNIQUE FUR OPTIMUM WELDING LENGTH AND POSSIBILITY 10 APPLY IT IN SHIPBUILDING
It is known that the welding process in the production field must be applied in. a certidn welding sequence. Accordingly, residual stresses as well as deformation can be controlled by temperature distribution on welded plates. In this case the welding length (length of block) nost be suitable in order to control interpass temperature between a weld and other (block and other) on the same we-ld line .Where the interpass temperature has a great influence with heat input. This paper presents a new technique for the estimation of optimum welding length as a function of heat input. This method depends on the calculation of cooling rates as a function of heat input. Then the time required for cooling to a certain temperature can be determined. The calculations are transferred into figures from which any date such as cooling rate and welding time can be obtained. The deduced time will be the total welding time till certain cooling time. The optimum welding length can be estimated on the basis of the electrode specifications such as size, kg weld metal per kg electrode, number of electrodes per kg weld metal, burn off time per electrode and welded length per burn off time per electrode. The possibility of application of such technique in shipbuilding is investigated. It is concluded thatthe proposed technique for estimating of optimum welding length can be applied effectively for controlling the residual stresses and deformation due to welding.
https://amme.journals.ekb.eg/article_57088_d3cf080d9d9ca8046961b7958ebd4641.pdf
1986-05-01
203
209
10.21608/amme.1986.57088
ISIIAK
SHEHATA
1
B.Sc.,M.Sc.,Ph.D,MAWS Lecturer,Shipbuilding Engineering Department, Faculty of Engineering at Port-Said, Suez Canal University, EGYPT.
AUTHOR
ORIGINAL_ARTICLE
SURFACE ROUGHNESS OF RAPIDLY SOLIDIFIED RIBBONS
This work aims to study the influence of processing variables in melt spinning - which is one of the rapid solidification processes (RSP) - on the surface roughness of the ribbons produced directly from the melt. The melt spinning is one of the recent manufacturing techniques, in which the final products - ribbons and fibers - could be produced directly by solidification of liquid alloys, thus saving all further conventional metal forming processes usually carried out. In this investigation, a melt spinning apparatus was designed and constructed in order to produce ribbons from the melt using a rotating substrate in the form of wheel. The alloys studied were aluminium alloys with 0, 5.23, 13.46 and 33 wt% Cu. The processing variables used were as follows: substrate linear velocity (v) ranging from 2 to 20 m.s , injection pressure of the melt (P) ranging from 2.9 X 104 to 6.8 X 104 N.m-2, substrate thermal conductivity (K) ranging from 43.3 to 386.6 W.m-I.K-1, melt superheating temperature ( AT) ranging from 0 to 150 K, nozzle - substrate distance (H) ranging from 5 to 20 mm and nozzle diameter (d) ranging from 0.5 to 2 mm. The surface roughness (Rt) has been measured and it was correlated with the different process- ing variables.
https://amme.journals.ekb.eg/article_57092_fe93ef30dcdb5f056ae80da3513ce9d7.pdf
1986-05-01
211
223
10.21608/amme.1986.57092
M.
Abdel-Ghafar
1
Design and Production Engineering Department, Faculty of Engineering, Ain-Shams University, Abbasia, EGYPT.
AUTHOR
N.
El-Mahallawy
2
Design and Production Engineering Department, Faculty of Engineering, Ain-Shams University, Abbasia, EGYPT.
AUTHOR
M.
Taha
3
Design and Production Engineering Department, Faculty of Engineering, Ain-Shams University, Abbasia, EGYPT.
AUTHOR
M.
Koura
4
Design and Production Engineering Department, Faculty of Engineering, Ain-Shams University, Abbasia, EGYPT.
AUTHOR
ORIGINAL_ARTICLE
Effect of electromagnetic stirring on the solidification morphology and mechanical properties of Al — alloys.
Three different Al-alloys were solidified in metallic molds under the application of magnetic field and direct current with the aim of improving its structure and mechanical properties. The results obtained from these experiments indicate that increasing the stirring power causes a remarkable grain refinement and improvement in the mechanical properties. The stirring force which was created from the the interaction between a magnetic filed of 1860 causes and a directcurrent of 230 amperes, Improves the ultimate tensile strength of the commercial pure Al( 99.5% ) by about 20% and its hardness by 42%. Corresponding values were (615 and 30%) and (62% and 25%) for the Al-4.3% Cu and the Al-11.7% Si alloys respectively. This improvement is most probably due to crystal multiplication and dendritic arms shearing.
https://amme.journals.ekb.eg/article_57096_1c675ae500096dd2ac1c946492bb5b5e.pdf
1986-05-01
225
236
10.21608/amme.1986.57096
Ashraf
Mohsen
1
Faculty of Engineering — Cairo University.
AUTHOR
M.
Sultan
2
Military Technical College
AUTHOR
M.
El—Salamoni
3
Faculty of Engineering — Cairo University
AUTHOR
ORIGINAL_ARTICLE
THE EFFECT OF THE FLANK TOOL WEAR ON THE MACHINABILITY OF METALS
The results obtained from tool life tests are presented, and a Taylor type tool life equation, taking both cutting speed and feed into consideration, is introduced. To study the effect of flank wear on the cutting process, different cutting tools having artificial wear land were used to simulate the action of naturally worn tools. A relationship between the power consumed in cutting and the amount of flank wear present was established, and thus enabling the tool wear to be evaluated during the machining operation.
https://amme.journals.ekb.eg/article_57181_bc912aee37a2d49eb9882a22c3aa4eaf.pdf
1986-05-01
71
78
10.21608/amme.1986.57181
Metal cutting
Machining
Tool life
Tool wear
Cutting force
Power consumption
M.
Riad
1
Associate Professor, Mechanical Design and Production Department, Cairo University, Egypt.
AUTHOR
M.
Abdelhamid
2
Assistant Professor, Production Engineering Department, Helwan University, Egypt.
AUTHOR
E.
Mohamed
3
Graduate Student, Production Engineering Department, Helwan University, Egypt.
AUTHOR
ORIGINAL_ARTICLE
ELECTROCHEMICAL CUTTING-PREDICTING EQUATIONS BY RESPONSE SURFACE METHODOLOGY (RSM) TO THE SELECTION OF OPTIMAL MACHINING VARIABLES.
The use of tubular cathodes considerably widens the technolo-gical possibilities in ECM of large-size components specially if the allowance will be removed in the form of a solid body. The present paper reports experimental investigations on this technique in the electrochemical cutting operation. Experiments were carried out to study the influence of machining parameters such as feed rate, applied voltage. electrolyte conductivity and electrolyte flow-rate on the width of cut, electrolysing current and volumetric metal removal rate. Experiments were planned on the basis of response surface methodology (RSM) technique. Three mathematical models correlating process parameters and their interactions with response parameters have been achieved. These models can be used in selecting optimum process parameters for obtaining the desired controlled width of cut with restricted consumed current.
https://amme.journals.ekb.eg/article_57185_13730ae2e8caa77d88817b3d011040d1.pdf
1986-05-01
79
89
10.21608/amme.1986.57185
M.
HEWIDY
1
Assistant Prof., Production Engineering & Machine Design Department, Faculty of Engineering and Technology, Menoufia University, Shebin El-Kom, Egypt.
AUTHOR
M.
FATTOUH
2
Associate Prof., Production Engineering & Machine Design Department, Faculty of Engineering and Technology, Menoufia University, Shebin El-Kom, Egypt.
AUTHOR
ORIGINAL_ARTICLE
IMPROVING ACCURACY OF ELECTROCHEMICAL MACHINING PROCESSES
The main difficulties regarding producing non-equal sided shapes such as parallelogram slots,airofoil grooves, elliptical holes, etc. are due to non equal gap distribution allover the machined surface.Such difficulty can restrict ECM industrial applications on a large scale. The scope of the present paper comprises an analytical and experimental model for studying various probabilities to overcome such difficulty and presents suitable recommondations for such practical situation. Experimental and theoretical results revealed that there is a significant improvement in both dimensional accuracy and power consumption obtained by the use of the proposed model. It has been found that in the present case. improving in accuracy and power consumption of about 21% and 28% respectively was obtained.
https://amme.journals.ekb.eg/article_57187_ac7bdd283046296eeedec3c94e2e0701.pdf
1986-05-01
91
100
10.21608/amme.1986.57187
A.
ABDEL MAHBOUD
1
Assistant Professor, Department of Production Engineering & Machine Design, Faculty of Engineering & Technology, Menoufia University, Shebin El-Kom, EGYPT.
AUTHOR
ORIGINAL_ARTICLE
OPTIMAL WORKING CONDITIONS IN ECM PART I : CIRCULAR HOLES
The present paper reports the results of an experimental program to study the influence of process parameters on the side gap value in the electrochemical drilling (ECD). Twenty-Seven tests were performed on an experimr ental test rig using mild steel workpieces. A 3' factorial design is used to,study the influence of feed rate, applied voltage and tool land on the side gap width. An empirical equation for the calculation of the side gap was presented which allows computing of the gap width within a tolerance of .05 mm. to 0.15 mm. Furthermore, this experimental techni-que will contribute towards the selection of optimum process conditions in the electrochemi-cal drilling processes.
https://amme.journals.ekb.eg/article_57188_79158564420558bfb3cdb834ce4e6ffb.pdf
1986-05-01
101
111
10.21608/amme.1986.57188
M.
HEWIDY
1
Assistant Prof., Production Engineering & Machine Design Department, Faculty of Engineering and Technology, Menoufia University, Shebin El-Kom, Egypt.
AUTHOR
M.
FATTOUH
2
Associate Prof., Production Engineering & Machine Design Department, Faculty of Engineering and Technology, Menoufia University, Shebin El-Kom, Egypt.
AUTHOR
ORIGINAL_ARTICLE
OPTIMUM CUTTING CONDITIONS FOR CERAMIC-TIPPED TOOLS
SPK-Cutting ceramics are high-performance cutting materials . based ona-aluminium oxide. Inserts in SPK-cutting ceramics: are unique in their high red hardness, extreme wear resistance and chemical stability. In addition, a fine-grained structure and suitable density provide these inserts with an extraordinary toughness and resilience.In this study, a turning tests have been conducted using three selected ceramic-tipped grades for cutting two different heat treatable steels. The experiment out line was set to evaluate the effects of the following factors on the tool performance, using the values of the flank wear as the measured variables :i) Tool Materials: Grades: SN56, SN60, and SH 1.ii) Work Materials: DIN: CK6O and 42CrM04.iii) Cutting Conditions: Cutting speed, feed rate, and cutting time.The optimum cutting conditions for minimum tool wear and maximum chip volume were obtained.The results shows that any increase in the cutting speed, feed or cutting time cause an increase in the wear. Therefore, the best cutting condition depends on the tool grades and work materials.
https://amme.journals.ekb.eg/article_57190_fa0bce4f5aa951bc608b9449c7634d90.pdf
1986-05-01
113
121
10.21608/amme.1986.57190
I.
MOBAREK
1
Assist. Prof., Production Eng. Dept., Faculty of Eng. and Technology, Helwan, Helwan University, Cairo, Egypt.
AUTHOR
ORIGINAL_ARTICLE
SURFACE QUALITY RELATED TO TURNING TOOLS
Surface quality is one of the important criteria to be considered for proper functioning of many machine parts. The study of the surface quality produced during the machining process with the different operation conditions will lead to better and satisfactory control over the degree of finish. In the present work, an experimental study of the relation between the surface quality and the cutting conditions, tool geometry and tool material is presented. Brass was used as a work material. The combined effects of the cutting conditions on the surface quality of the machining surfaces were discussed. It was found that the feed rate and nose radius have major effect on the surface quality. A relationship between nose radius and feed rate indicated that the nose radius should be three times or more of the feed rate. However, it should be remembered that if the nose radius is too large, it may cause chatter.
https://amme.journals.ekb.eg/article_57191_83d04bc0cacb0b35db6980e54c97c6cf.pdf
1986-05-01
123
129
10.21608/amme.1986.57191
I.
MOBAREK
1
Assist. Prof., Production Eng. Dept., Faculty of Eng. and Technology, Helwan, Helwan University, Cairo, Egypt.
AUTHOR
ORIGINAL_ARTICLE
MATHEMATICAL OPTIMIZATION VERSUS SIMULATION FOR THE SELECTION OF CUTTING PARAMETERS FOR C.A.M.
This paper investigates the fasibiliLy of applying mathematical programming and heuristic simtlation algorithms for the optimal selection of cutting parameters in M/C tools. Recently, this problem has become of major interest to researchers working in the area of Computer Aided Manufacturing (C.A.M). The concepts and methods developed in this paper are very useful for the production engineers and can be successfully applied for semi-automatic and automatic machine tool production centres as well as Numerically Controlled M/C Tools or direct numerically controllel M/C centres (DNC) and FMS.
https://amme.journals.ekb.eg/article_57192_736c560dca8e935434ca659ca745f897.pdf
1986-05-01
131
144
10.21608/amme.1986.57192
Soad
Serag
1
Dr., Associate Professor, Production Engg. & Machine Design Dept., Faculty of Engineering & Technology, Menoufia University, Shebin El-Kom, EGYPT.
AUTHOR
ORIGINAL_ARTICLE
FEW IMPROVEMENTS ON THE CHARACTERISTICS OF Xˉ AND R CONTROL CHARTS
The Xˉ and R control charts have been used as an effective tool for carrying out process control from the standpoint of statistical quality control. However, the 3σ method is not so powerful in testing arousing a feeling of dissatisfaction particularly when controlling production processes. In other words; when process shift is not so great, the Xˉ ,and R control charts does not have a strong power of test and it is sensitive to dispersion, showing the possibility of carrying out wrong control. Hence,the purpose of this paper is to study the characteristics of process adjustment on the basis of the Xˉ and R control charts, and we have proposed the run method as a measure to remove these defects of the charts.
https://amme.journals.ekb.eg/article_57193_9ccc83872e7f069c37a2cbe958eb3462.pdf
1986-05-01
53
60
10.21608/amme.1986.57193
SAYED
MOHAMED
1
Lecturer ,Production Engineering and Design Department, Faculty of Engineering and Technology, Minia University.
AUTHOR
ORIGINAL_ARTICLE
LOCAL PRESSURE LOSSES FOR SCMC AQUEOUS SOLUTIONS IN PIPE-FITTINGS
Local priissure losses for Sodium Carboxymethyl Cellulose (SCMC), aqueous solutions in pipe-fittings were experimentally measured, for concentrations range from 0.03 to 1.1 wt.%. Pressure drop-flow rate relation has shown similar behaviour, (power expression), to that of pipe flow with the same power. Correlations were predicted for the evaluation of press-ure drop in different pipe- fittings, which enable to estimate the local losses for another pseudoplastic fluids if the behaviour equations are found.
https://amme.journals.ekb.eg/article_57195_3fe4922c4821f86d846aa64b2a1f2d60.pdf
1986-05-01
61
69
10.21608/amme.1986.57195
Ibrahim
SALEH
1
Ph.D., Military Technical College, Kobry el Kobba, Cairo.
AUTHOR
M.
HAMZA
2
Eng., Armament Authority, Kobry el Kobba, Cairo.
AUTHOR
M.
HARIDI
3
Ph.D., Military Technical College, Kobry el Kobba, Cairo.
AUTHOR
ORIGINAL_ARTICLE
Mathematical Models For Integrated Production Planning As Application in Inventory Control
In mechanical industry products are usually manufactured by assembling a large number of subromponents. The production and stocking of such components are often of much greater significance then the assembly and stocking of final products. The problem is set within a multicriteria framework, and the consequences of the tactical decisions are presented to the decision maker as goal outcomes. The methodology involves embedding relatively simple models within a larger and more comlex model. The large total model is a simulation model which uses the optimal decisions of the inventory model to determine the strategic concequences for each important criterion. The methodology was applied to an inventory system of a manufacturer of spare parts for cars. The results of that application are reported in some detail. Of particular interest is the comparison of two inventory models: the economic order quantity model and a stochastic inventory model. These two models are compared on the basis of their performance in producing desirable strategic consequences.
https://amme.journals.ekb.eg/article_57198_4cae05a77680f895cc743fac5db57825.pdf
1986-05-01
71
80
10.21608/amme.1986.57198
Farouk
Rashed
1
Dr. Eng., Associate Professor, Production Engineering Dept., Faculty of Engineering & Technology, Helwan University Cairo.
AUTHOR
ORIGINAL_ARTICLE
EFFECT OF STABILIZING PLATE PLACED IN ENTRANCE BEND OF AN AXIAL PUMP
For the axial pumps, the inlet bend of 90° affect widely the prerotation, losses and the pump performance as well. A stabilzing plate has been placed in the entrance bend, in the plane of curvature, to minimize these effects. Experimental investigations have been carried out for the pumping head, power and cavitation characteristics. It has been found that the stabilizing plate improves the pump performance at normal and higher flow rates. At partial discharges, the results showed that the pump performance is lower due to supplementary losses due to plate. The cavitation ability has been found to be improved at normal and higher flow rates.
https://amme.journals.ekb.eg/article_57199_3f9eb7becb961ee13302979d52c5cf63.pdf
1986-05-01
91
97
10.21608/amme.1986.57199
Ail
Barakat
1
Dr., Mechanical Power Department, Military Technical College, Kobry el Kobba, Cairo, Egypt.
AUTHOR
Ibrahim
Saleh
2
Dr., Mechanical Power Department, Military Technical College, Kobry el Kobba, Cairo, Egypt.
AUTHOR
ORIGINAL_ARTICLE
THE STRUCTURE OF BIFURCATIONS OF CRITICAL POINTS OF A DIFFERENTIAL EQUATION WITH SEVERE NON-LINEARITY .
The critical points of an autonomous differential equation of the second order with severe non-linearity , can have a bifurcation structure in a parameter plane (a,b) , -1Gb <1 , similar to the " box-within-a-box " bifurcation structure . This is shown using a recurrence relation having such a bifurcation structure in (a,b) plane , -1 <b <I .
https://amme.journals.ekb.eg/article_57201_52f883f3a7f96702da1fc4d08c89389b.pdf
1986-05-01
99
104
10.21608/amme.1986.57201
HASSAN
EL-HAMOULY
1
DEPARTMENT OF MATHEMATICS - MILITARY TECHNICAL COLLEGE - EGYPT.
AUTHOR
ORIGINAL_ARTICLE
COMPARATIVE SIUDY OF SEVERAL PARAMETER ESTIMATION TECHNIQUES FOR A CERTAIN CLASS OF DYNAMIC SYSTEMS
The desire of the practical engineers has been to obtain better knowledge of specific plants, thus facilitates the design of improved control systems and consequently lower operating costs. In general the identification problem is characterized by three elements :— Mathematical models of the systems— Input signals— Criteria for best estimationRegarding to these elements, the auther has chosen the most common mathematical models (and the related algorithms) suited for linear time invariant system with finite memory. At the same time, the used algorithms do not make strict limitations on the input signals. With respect to the criteria, it was chosen to be a functional of the error of the output response. A comparative measures of parameter estimation for three algorithms have been introdces. These algorithms are :— The algorithms derived by the auther— The algorithms derived by. R. Subbayyan; R.Nagarajan— The algorithms derived by. L.C. Westphal.
https://amme.journals.ekb.eg/article_57204_6218f1be5b636cec8e7a72b0f6c7e321.pdf
1986-05-01
105
116
10.21608/amme.1986.57204
E.
ZAKZOUK
1
DR., ( PH.D )., Deputy chief of optoelectronic and automatic control department, M.T.C, Cairo.
AUTHOR
ORIGINAL_ARTICLE
DEFORMATION OF SURFACES IN RIEMANNIAN 5-SPACES
Let M:D→V5 and Mˉ:D→Vˉ5 (D ⊂ R2) be two surfaces in the second order deformation in the Riemannian 5-spaces V5 and Vˉ5 of curvatures R, Rˉ respectively. Let L: Tm (V5)→Tm (Vˉ5 ) be an isometry such that L(dm/dt) = dmˉ/dt' 𝝅: Tm(V5)→n = {V5}. Then M and Mˉ are in the third order deformation provided that:
1- The Gaussian curvature K and the curvature k of the normal bundle satisfies K2-k2 ≠ 0 on M.
2- dim T2m (M) = 4 on M.
3- M has no non-trivial real conjugate directions at each of its points
4- L {R(x,y)z} = Rˉ(Lx,Ly)Lz, and L{𝝅R(x,y)u} = 𝝅ˉRˉ(Lx,Ly)Lu for each x,y,z ϾTm(M), u Ͼ Nm(M) ={v3,v4}.
5- M and Mˉ are in the third order deformation on 𝜌 D.
https://amme.journals.ekb.eg/article_57231_966e8321221c27339ce5baecf03e140f.pdf
1986-05-01
117
129
10.21608/amme.1986.57231
Ramy
Talaat
1
Gen. Dr.
AUTHOR
ORIGINAL_ARTICLE
MATHEMATICAL MODEL OF VEHICLE STARTING SYSTEM
For starting the Internal Combustion Engine I.C.E. the motor vehicle must be equiped with a starting system which converts the electrical energy into, the mecanical energy needed for putting the I.C.E. in function. This paper deals with the main characteristics of starting system elements. A linear and non linear mathematical models have been analysed for the st-arting system under investigation .
https://amme.journals.ekb.eg/article_58946_64cdfbc81c58d70d9b3724d8127b29eb.pdf
1986-05-01
131
137
10.21608/amme.1986.58946
A.
LOTFY
1
Col.(Ph.D) ,Department of Tanks, M.T.C., Cairo.
AUTHOR
A.
EL.SANABARY
2
Col.(Ph.D) ,Department of Machine Design, M.T.C., Cairo.
AUTHOR
ORIGINAL_ARTICLE
ON PERIODIC SOLUTIONS OF SECOND ORDER DIFFERENTIAL EQUATIONS
In this paper we establish sufficient conditions for the existence of periodic solutions of the equationx + K(x — a) (x — b) x + Ͼ x2n+1 (x — c) = 0,This equation does not satisfy the condition xg (x) ) ˃ 0 for l x l >0 which was assumed in [3] and [5] .
https://amme.journals.ekb.eg/article_58959_ae20c7fdf925d6d21b7c4cf2e16e58fa.pdf
1986-05-01
139
148
10.21608/amme.1986.58959
M.
Hosam El-Din
1
Military Technical College, Cairo.
AUTHOR
F.
Holail
2
Technical Research Department, Presidency, Cairo.
AUTHOR
ORIGINAL_ARTICLE
THE BRAUER CHARACTERS AND THE CARTAN MATRIX FOR SL (2 , p)
One way to study the representation theory of a group is to get hold of the simple modules. Finding the multiplicities of these simple modules as composition factors of the principal indecomposable modules (PIM) is a step in this way. These multiplicities are the entries of the Cartan matrix. In this paper, we use the " Orthogonality Relation " (theorem 60.5 ,[12]) of the Brauer characters to get the inverse of the Cartan matrix for the finite Chevalley group of type A1(SL (2,p)) .
https://amme.journals.ekb.eg/article_58981_91f8b44b6b4ac9a75d9fff9a471b2c3f.pdf
1986-05-01
149
158
10.21608/amme.1986.58981
SAMY
YEHIA
1
Military Technical College, Cairo,Egypt.
AUTHOR
ORIGINAL_ARTICLE
GENERALIZED FISHER'S INFORMATION AND POINT ESTIMATION THEORY
The aim of this paper is to introduce a generalized form of Fisher's information based on the concept of divergence of a sample of size n for different values of the population parameter. By using this generalization, we obtain a new form;less restricted, of cramer-Rao inequality. Some illustrative examples are presented.
https://amme.journals.ekb.eg/article_58985_43d7e9f7db4534067326e064124799cf.pdf
1986-05-01
159
168
10.21608/amme.1986.58985
Fouad
Abbady
1
Military Technical College, Cairo - Egypt.
AUTHOR
ORIGINAL_ARTICLE
FINITE ELEMENT PREDICTION OF UNSTEADY HEAT TRANSFER IN HOLLOW BLOCKS
This paper presents a numerical method for describing the transient heat transfer through hollow cement blocks via the employment of finite element technique. The block under consideration is assumed to be of rectangular cross-section and composed of two parts, a solid inside which an enclosure (space) is located. The outer surface of the block is exposed to the solar flux. The temperature distribution inside the block as function of space coordinates and its variation with time are the unknown variables of the problem. This leads to a parial differenial equation in the temperature. Finite element technique is used to obtain the solution of the problem for different boundary conditions. The effect of the presence of the enclosure is investigated by comparing homogeneous and hollow blocks results.
https://amme.journals.ekb.eg/article_58989_da0f2a9c6bd62b85d2f3135cc8da4360.pdf
1986-05-01
169
181
10.21608/amme.1986.58989
Ghazy
Assassa
1
Associate Professor., Dept. of Mech. Eng., Faculty of Engineering at Shoubra, Zagazig Univ., 108 Shoubra Street, Cairo, Egypt
AUTHOR
Eed
Abdel-Hadi
2
Assistant Professor., Dept. of Mech. Eng., Faculty of Engineering at Shoubra, Zagazig Univ., 108 Shoubra Street, Cairo, Egypt
AUTHOR
ORIGINAL_ARTICLE
OSCILLATIONS OF FUNCTIONAL-DIFFERENTIAL EQUATIONS GENERATION BY SEVERAL RETARDED AND ADVANCED ARGUMENTS
In this paper I study the oscillatory behaviour of equations(*) yi(t)+qy(t)+±17 piy(t- ri).0 and (**)yi(t)-gy(t) -i=1 i=1where q?, 0, pi> 0 and ti 0, are constants, i=1, ,n. Iteach of the following conditions (1)pit exp(14-q ti) > 1 fo, n, (2) ( l pi) exp (1+q )2- >1, where = min Iry t2,A*Military Techinical College, Cairo. Egypt. Department of MatheMatics .of the forms p.y(t+r.1 )=Dsis proved that r some i,1=1,2,../tn),(3)t(17p.)( S. )exp(n+q ti) 1, or (4) CZ' (q/n+ . ) j i > e impliesiri i i i pii T12 2 n impliesi=1 i=1that every solution of (*) or (**) oscillates. A generalization in thecase where the coefficients q>, 0, pi) 0 1=1,...,n are continuous functions of t is also presented.
https://amme.journals.ekb.eg/article_58999_1661b1679b393e8fe2e1ee13012ccebf.pdf
1986-05-01
183
200
10.21608/amme.1986.58999
Medhat
El ZANFALY
1
Military Techinical College, Cairo. Egypt. Department of Mathematics.
AUTHOR
ORIGINAL_ARTICLE
Nonlinear Multi parameter Problems in Banach Space
In this paper we study the problems of existence and uniqueness of solution to the nonlinear multiparameter problems of the formAu + 2]1 J B.0 = f,j= Jwhere A, B.: X--X are mappings from a reflexive Banach space X into its dual space X , satisfying certain monotonicity corications,fEXIand),,.(j=1,21...,n) are in general complex parameters.
https://amme.journals.ekb.eg/article_59010_37f43bc55d51cf946acee6cbca839e9b.pdf
1986-05-01
201
211
10.21608/amme.1986.59010
M.
Amer
1
Department of Math.,Military Technical College,Cairo,Egypt.
AUTHOR
B.
Ahemed
2
Department of Math. University Collage of Women, Ain Shams University, Cairo, Egypt.
AUTHOR
ORIGINAL_ARTICLE
MATRIX METHODS IN MAGNETOHYDRODYNAMICS
The matrix form of magnetohydrodynamics (MHD) is presented. The approach follows the recent development of matrix methods in optics. Maxwell's equations, Ohm's law, the equation of continuity, the equation of motion with the JxB body force and the energy equation were formulated in matrix form without using vector or tensor analysis. These equations were applied to describe the propagation of plane MHD waves in conducting fluids. Two transverse modes were obtained due to z, coupling between viscous and magnetic diffution and Alfven wave. The ordinary acoustic waves was found to split into fast, slow and intermediate magnetoacoustic waves.
https://amme.journals.ekb.eg/article_59015_10cb614d21abb54134729c0f1704ab5b.pdf
1986-05-01
213
220
10.21608/amme.1986.59015
M.
Hassan
1
Department of Physics, Military Technical College, Cairo.
AUTHOR
F.
Hammouda
2
Department of Physics, Military Technical College, Cairo.
AUTHOR
A.
Asser
3
Department of Physics, Military Technical College, Cairo.
AUTHOR
ORIGINAL_ARTICLE
AN ADVANCED FORMULATION FOR THE CLASSICAL METHOD OF TREFFTZ FOR 2D POTENTIAL PROBLEMS
In this paper a variation of the usual Vrefftz method is presented and applied to harmonic problems. Here, the fundamental solutions of the given problem are employed as expansion functions and their singularities are located outside the domain of the problem to avoid any handling of a singul-ar quantities. This method has a significant computationsal advantage in that here no integrations are required. Test problems have been analysed using tie proposed method and the results compared with those generated by the ReHlar Boundary Element Method using continuous and partially - dis-continous elements.
https://amme.journals.ekb.eg/article_59020_adb0db4c8334a0f2676cee396ba7aee2.pdf
1986-05-01
221
228
10.21608/amme.1986.59020
N.
EL Sebai
1
Department of Mechanics and Elasticity, The Military Technical College, Kobry El Kobba, Cairo, Egypt.
AUTHOR
Z.
Momeh
2
Department of Mechanics and Elasticity, The Military Technical College, Kobry El Kobba, Cairo, Egypt.
AUTHOR
ORIGINAL_ARTICLE
On the Oscillation of Functional-Differential Equations
In this paper it ispproved that for the RDE y"(t)- E pi(t) y(gi(t))=f(t), every bounded solution is oscillatory under certainiconditions imposed. on the functions pi,gi and f for i=1,2,..,n.
https://amme.journals.ekb.eg/article_59023_ee084580caea154f47127eaaf4dc4938.pdf
1986-05-01
229
234
10.21608/amme.1986.59023
MEDHAT
EL-ZANFALY
1
Department of Mathematics, Military Technical College Cairo, Egypt.
AUTHOR
ORIGINAL_ARTICLE
STABILITY ANALYSIS FUR NILE'S VESSELS
The final stability assesment for Nile Cruises vessels,Launches and Ferries taken into account the effect of shapes and the actual location of the C.G. are important for the safety considerations for such vessels. Analysis for gathered data for various existing vessels are introduced with curves and tables to give an aid for owners and builders in selecting principle dimen-sions for preliminary design stages. Practical.application is given to illu-strate the benifit of the presested analysis and to show the effect of proposed alteration to improve the stability characteristics for a given vessel.
https://amme.journals.ekb.eg/article_59024_8131b30a54c2def7b5b61f4a4f052cff.pdf
1986-05-01
235
250
10.21608/amme.1986.59024
A.
AMIN
1
LECTURER,SHIP ENGINEERING DEPT. FACULITY OF ENGINEERINGA TECHNOLOGY SUEZ CANAL UNIVERSITY PORT-SAID, EGYPT.
AUTHOR
ORIGINAL_ARTICLE
IMPLICIT TIME-DEPENDENT METHOD FOR THE CALCULATION OF TRANSONIC BLADE-TO-BLADE FLOWS WITH STRONG SHOCK WAVES
Based on Euler equations, an implicit time-dependent method is applied for the calculation of the transonic blade-to-blade flows with strong shock waves. The ntmerical method is based ' on a fully implicit time difference scheme. The stabilizing correction method is utilised as an ADI sequence to break down the two dimensional operator into two operators. These opera-tors are selected so that at each time step the variables are determined independently of each other. The work presented here is an adaptation, to turbomachinery flows, of the basic method previously publicized and well applied in the internal nozzle flow. The purpose of this paper is to examine the ability of this method to predict the blade-to-blade transonic flow with strong shock waves. Detailed studies of the grid system and corresp-onding problems related to the boundary (inlet,exit and perio-dicity) conditions. Results are presented for the ECDEV tran-sonic compressor cascade with prescribed pressure ratio and with a strong passage shock. The results obtained are compared with those obtained by an explicit method utilised at ONERA - FRANCE.
https://amme.journals.ekb.eg/article_59030_6b2e40fe6f6a7072c4e83ba823bcd008.pdf
1986-05-01
251
262
10.21608/amme.1986.59030
Mohamed
ABDELRAHMAN
1
Assistant Professor, Dpt.of Aeronautics,Cairo University,EGYPT.
AUTHOR
ORIGINAL_ARTICLE
ON PRESERVING THE STABILITY OF A PERTURBED HURWITZ POLYNOMIAL
Necessary and sufficient conditions for a perturbed polynomial to remain Hurwitz are given. The conditions do not require a priori knowledge of the bounds on coefficient perturbations and allow the designer maximum freedom in allocating different weights to various coefficients to reflect different levels of uncertainty in the coefficients. The conditions are an extension of a previous result of the author in which suf-ficient conditions for the same problem were obtained.
https://amme.journals.ekb.eg/article_59033_5b05d20d291eb0c16499357517caae7d.pdf
1986-05-01
263
268
10.21608/amme.1986.59033
Mohammad
Argoun
1
Assistant Professor, University of Wisconsin-Milwaukee, P. O. Box 784 Milwaukee, Wisconsin 53201
AUTHOR
ORIGINAL_ARTICLE
THE NEED FOR ROBOTS
Industrial robots are now a reality. They are having an impact in the field of automation such that they have come to symbolize high-level industrialization of a society. An argument has continued that introducing robot technology causes unemployment. However, as the economy improves with the introduction of the high-level robot technology, several em-ployment opportunities will be opened up. Fortunately, robot technology may provide the only opportunity of developing countries to speed-up offsetting their lack of competitiveness, to narrow down the existing tech-nological gap between them and the industrialized countries, and to bring a bright future for their economies. Therefore, robot technology should receive much more attension. Robots are defined and a historical background is presented. Existing industrial robots are reviewed and some future prespectives are presented. The sociological and economical impacts of robot technology in the society of man is then studied. A few of the general categories where robots are and can be used are listed. Applications in the fields of industrial automation and energy, specially oil drilling and coal mining, are stutied in some detail. Finally, the urgent needs of developing countries for the adaptation of the robot technology in order to get to the race and to keep their competitiveness is stated. It is hoped that this state-of-the-art study of robot technology presented here will enhance the introduction and adaptation of this technology.
https://amme.journals.ekb.eg/article_59040_7b21667b5cb4210e092c560bef42a5c5.pdf
1986-05-01
57
65
10.21608/amme.1986.59040
MAHER
MOHAMED
1
Lecturer, Mechanical Engineering Department, Faculty of Engineering and Technology, El-Minia University, El-Minia, Egypt.
AUTHOR
ORIGINAL_ARTICLE
COMPUTERIZED CLASSIFICATION AND CODING FOR AUTOMATIC PROCESS PLANNING SYSTEMS
The development of a computerized process planning system requires a comprehensive description of the workpiece in terms of geometry and form elements, so that a sufficiently detailed workpiece model is required. The classification code is the logical tool for breaking up the workpiece spectrum into input data to be analysed by digital computers.The fulfillment of the complete automation of the process planning can be achieved through the computerization of all the involved activities. All the reviewed automated process planning systems are based on manual workpiece classification and coding. The work presented in this paper is concentrated on the development of a computer aided workpiece classificationand coding method which can be used in any automated process planning system.
https://amme.journals.ekb.eg/article_59044_9d23b5eea82b56258ef29bcf3fa2a3bd.pdf
1986-05-01
67
81
10.21608/amme.1986.59044
M.
El Hakim
1
Prof. Of Prod. Engng., Faculty of Engng., Ain Shams Univ., Cairo.
AUTHOR
A.
El Awam
2
Dr., Shoubra Co. for Engng. Industries (MF 27), Cairo.
AUTHOR