ORIGINAL_ARTICLE
ACTIVE CONTROL EFFECT ON REDUCING NOISE AND RESONCE AMPLITUDE OF CLAMPED PLATE
ABSTRACT:
Noise and vibration control of plates using active elements is presented here as a result of experimental work. The objective of this work is to study the possibility of controlling the noise and vibration of plates using a simple control regime. Active reduction of plate′s noise and vibration is evaluated for a test steel plate excited using a B&K exciter. Smart damping materials (piezo-ceramics) are used for accomplishing the process of reducing the plate vibration and born noise. The system is built up with an analogue to digital converter fed with the measured vibration signal after passing through a low –pass filter. The output is manipulated through a computer to produce an analogue signal using a digital to analogue converter, which is fed to the piezo-ceramic actuator without any frequency modifications. The actuator vibrates in response, to counter act and to damp the structure vibration. The test results show that the vibration peaks at multiple frequencies are reduced. It also shows that the structural borne noise is substantially reduced using smart damping materials, indicating the validity of its usage for industrial applications to reduce noise and vibration.
https://amme.journals.ekb.eg/article_41156_144a529c96a3ecd96b3c1b512d051645.pdf
2006-05-01
718
724
10.21608/amme.2006.41156
Active control
Smart materials
Piezo-ceramics
Viberation
Noise
Ghazy
R.
1
Dep. of Mechanical Engineering Design, Faculty of Engineering, Zagazig University.
AUTHOR
Elhady
M.
2
Dep, of Space Science, National Authority of Remote Sensing and Space Science, Egypt.
AUTHOR
ORIGINAL_ARTICLE
Shock absorber characteristics representations and vehicle performance evaluation
ABSTRACT:
The main objective of the present work is to study theoretically and experimentally how the ride performance is affected by shock absorber representation. To achieve this goal, mathematical modeling of vehicle suspension system is introduced, and the MATLAB/SIMULINK and ADAMS software are used for numerical simulation. The shock absorber characteristics are measured experimentally. An advanced test rig for measurement, recording, and computer analyzing the readings is used. The time history of force applied, the force versus displacement and force versus velocity are given in sheet and also in graphs.
An analysis of the obtained results considering the actual measured characteristics has been carried out. For the considered vehicle, it is concluded that, the actual shock absorber representation improve the response of sprung mass acceleration up to (37%), pitch acceleration up to (74.3%), vehicle ride index up to (58.4%), and vehicle road holding up to (-4.25%)compared to the results obtained using linear shock absorber approximation.
https://amme.journals.ekb.eg/article_41184_269f4838cb8d82b34f32086a52a17f01.pdf
2006-05-01
369
382
10.21608/amme.2006.41184
shock absorber
Vehicle ride
Vehicle handing
Vehicle performance
Al-Maqtri
A.
1
U.A.E. Armed forces.
AUTHOR
Hegazy
A.
2
Egyptian Armed Forces.
AUTHOR
Hossamel-deen
H.
3
Philadelphia University, Amman , Jordan.
AUTHOR
ORIGINAL_ARTICLE
SIDE-STICK CONTROL OF POWER RACK AND PINION STEERING SYSTEM
ABSTRACTNowadays, a great development is occurring in the automotive systems due tointroduction of electronics, which act as an integrated part with the mechanicalsystem. The result of this integration appeared as an improvement in all phases ofautomotive functions as: driving performance, fuel efficiency, exhaust purification,safety & comfort.The objective of this research is to control electronically the steering in a vehicle withpower steering system using a side-stick. To achieve this goal an electronicallycontrolled module is proposed, realized and implemented on a steering system. Thismodule is operated using a side stick and the necessary sensors and actuators whichreplaces the conventional steering wheel.An embedded controller is used as a control unit and the required interfacing circuitsare designed and implemented. For investigation of the control system, amathematical model is prepared. Finally the overall test rig is built-up and the controlsystem testing showed a great benefit in modifying a conventional steering system tobe electronically controlled. The simulation results agree to a great extent with thereal test results.
https://amme.journals.ekb.eg/article_41261_e1248c206371a24ac0e6593270cd0722.pdf
2006-05-01
383
396
10.21608/amme.2006.41261
Rack & Pinion
Side-Stick Steering
Embedded controller
Electronic control
Asfoor
Sh.
1
Egyptian Armed Forces.
AUTHOR
Ebraheem
H.
2
Egyptian Armed Forces.
AUTHOR
El-Haddad
A.
3
Higher Institute of Technology-10th of Ramadan.
AUTHOR
ORIGINAL_ARTICLE
Evaluation of tracked vehicle performance characteristics
ABSTRACT:
Performance characteristics of tracked vehicles are the principal measure of their dynamic and it is disturbed by any change in vehicle technical specifications. This paper evaluates the performance characteristics of Armor Personal Carrier M113 and its variation due to additional forces and masses resulting from increasing of vehicle capabilities such as fire power, degree of armor protection and mobility. Performance of vehicles is determined through number of characteristics like dynamic, acceleration, steering and suspension characteristics. These characteristics are evaluated theoretically using vehicle technical specifications as input data for the vehicle. For suspension characteristics the parameter of damping coefficient of APC M113 shock absorber is measured in a special test rig and is introduced in the equation of motion to find the vehicle response. Accuracy of results is depending on the accuracy of input data and method of calculations. The evaluated characteristics are used for comparison between performance of different vehicles and also for comparison between performance of the same vehicle after increasing its capabilities.
https://amme.journals.ekb.eg/article_41311_b8eba5cf47e38cfd0e12d01e1159b455.pdf
2006-05-01
397
409
10.21608/amme.2006.41311
Dynamics
Tracked
vehicle
and Vibration
Salem
M.
1
Egyptian Armed Forces.
AUTHOR
Galal
W.
2
Egyptian Armed Forces.
AUTHOR
ORIGINAL_ARTICLE
RECONSTRUCTION OF DIESEL EGINE CYLINDER PRESSURE USING VIBRATION AND ACOUSTIC EMISSION
ABSTRACT:
In this paper the diesel engine cylinder pressure is reconstruction in the crank angle domain using the measured engine vibration and acoustic emission. This technique depends on frequency analysis of engine vibration and acoustics. The frequency response functions (FRF′S) are determined from the measured cylinder pressure, engine vibration and acoustic emission at specified engine speed and loads. The cylinder pressure is reconstructed from the measured engine vibration and acoustics at similar conditions by applying the inverse filtering technique using the already determined FRF′S. The measured and the reconstructed cylinder pressures are compared to each other for vibration and acoustics at different loads. Comparison between the reconstructed cylinder pressure from acoustics and vibration signals at the similar speeds and loads with the measured ones show good results as they are predicated. Slight differences in results for measured and reconstructed cylinder pressure for both vibration and acoustics is due to non-linearity of the engine system. The measured and reconstructed cylinder pressures from vibration signal are compared to that ones from acoustics for similar conditions and they have the same results.
https://amme.journals.ekb.eg/article_41368_895a1a072ffd423cf6112f42ab65f19a.pdf
2006-05-01
510
525
10.21608/amme.2006.41368
Cylinder pressure
Vibration
acoustics
frequency response function
fast fourier transform and inverse filtering
Badawi
B.
1
PhD Postgraduate candidate, Dept. of Mech. Power and Energy, Military Technical Collage, Cairo, Egypt.
AUTHOR
A.
Elmaihy
2
Egyptian Armed Forces.
AUTHOR
Samy
S.
3
Egyptian Armed Forces.
AUTHOR
Shahin
A.
4
Assistant Prof., Faculty of Engineering, Modern University of Engineering and Technology, Cairo, Egypt.
AUTHOR
Mohamed
I.
5
Egyptian Armed Forces.
AUTHOR
ORIGINAL_ARTICLE
EVALUATION OF LOCAL HUMPS AND A NEW HUMP DESIGN
ABSTRACTThe number of speed humps (sleeping policemen) in many countries has beenincreased steadily in the last decades. In this paper, the problem of installing nonspecifiedroad humps in Cairo city has been studied. A simple measuring techniquehas been constructed to measure hump profiles at different zones in Cairo.Evaluation of the humps has been discussed based on the dynamic response ofcrossing vehicles. This evaluation shows that road humps are randomly installeddepending on resident requirements which satisfy safety in their neighborhoods.Many of these humps may cause vehicle damages and driver discomfort; therefore,optimizing an ideal hump becomes one of the traffic control requirements. Optimizedhump dimensions for a new hump shape is introduced. The extreme acceleration ofthe driver’s seats of a truck and a passenger car is set as a multi objective functionfor the optimization process. The road-holding ability represented by the tire lift-offspeed has been taken into consideration. The optimal calculations are based onGenetic Algorithm (GA) for its advanced searching ability. The results showed that,optimized humps are favorable than the current local and standard humps for bothpassenger cars and trucks.
https://amme.journals.ekb.eg/article_41369_75df07e93f2499c208dcdc93c793f5cc.pdf
2006-05-01
526
539
10.21608/amme.2006.41369
Road humps
Speed Control
Vehicle dynamics
vehicle suspension
global optimization
Ride comfort
road-holding ability
ground clearance
Younes
K.
1
Professor, Mechanical Design Department, Helwan University – Faculty of Engineering – Mataria.
AUTHOR
El Demerdash
M.
2
Professor., Automotive Engineering Department, Helwan University – Faculty of Engineering – Mataria.
AUTHOR
S.
El Adl
3
Associate Prof, Mechanical Design Department, Helwan University – Faculty of Engineering – Mataria.
AUTHOR
Hani
S.
4
Graduate Student, Mechanical Design Department, Helwan University – Faculty of Engineering – Mataria.
AUTHOR
ORIGINAL_ARTICLE
INVESTIGATION OF LATERAL FLYING QUALITIES OF AIRCRAFT
ABSTRACTMethodology for investigation of lateral flying and handling qualities of an airplane isfound based on stability analysis. The fighter aircraft (F4C) and the jet trainer aircraftare used as an example models in this investigation. Effect of changing the rollingmoment due to sideslip (Lβ) and the yawing moment due to sideslip (Nβ) derivatives onlateral-directional motion characteristics and flying qualities is evaluated for both models.For the lateral-directional motion the MIL-F-8785C specifications were used to comparethe parameters (time to double or to half amplitude in the spiral mode (T2s), roll modetime constant (Tr), damping ratio (ζd), and undamped natural frequency (ωnd) of thedutch roll mode) with the minimum or maximum required limits of flying qualities.
https://amme.journals.ekb.eg/article_41371_cccfcbdc1cf1ba535f712ac9aaac7016.pdf
2006-05-01
540
558
10.21608/amme.2006.41371
Flying qualities
handling qualities
and airplane stability analysis
Mohamed
O.
1
Karary Academy of Technology, Sudan.
AUTHOR
Bayoumy
M.
2
Egyptian Armed Forces.
AUTHOR
Elshabka
M.
3
Egyptian Armed Forces.
AUTHOR
Ibrahim
M.
4
Design and Development Center.
AUTHOR
ORIGINAL_ARTICLE
NATURAL FREQUENCIES OF THIN COMPOSITE PLATES SUBJECTED TO STATIC LOADS
ABSTRACTThe objective of this work is to study the dynamic behavior of thin flat rectangularcomposite plates when subjected to static loads. A program for calculating the load atfirst ply fracture was made to estimate the maximum loads that can be carried byeach specimen. The natural frequencies of the plate, using finite element program(ANSYS) are obtained considering the fractions of these failure loads. The staticdeflection corresponding to the applied static loading changes the assumption ofstraight flat plate to a curved one. An experimental modal test was made to verify thefinite element technique. The comparison between numerical and experimentalresults is carried out. The effect of combined load on the natural frequencies forcomposite plates with different fiber types, different fiber orientations and at differentload locations are estimated.
https://amme.journals.ekb.eg/article_41372_2aba6064732ca7d98210474780d6f59c.pdf
2006-05-01
559
572
10.21608/amme.2006.41372
Thin Plate
Composite and Natural Frequencies
Ahmad.
B.
1
Professor, Higher Technological Institute, 10th of Ramadan City, Egypt.
AUTHOR
Raafat.
G.
2
Professor, Dept. Of Mechanical Design, Mataria, Helwan University, Cairo, Egypt.
AUTHOR
Tarek.
E.
3
Associate Professor, Dept. Of Mechanical Design, Mataria, Helwan University, Cairo, Egypt.
AUTHOR
Ahmad.
S.
4
Egyptian Armed Forces.
AUTHOR
ORIGINAL_ARTICLE
ELIMINATION OF UNBALANCE IN MAGNETIC BEARING SYSTEMS WITH NEURO-FUZZY REDUCED ORDER OBSERVER
ABSTRACTAdaptive Neuro-Fuzzy Inference System (ANFIS) is used to design fuzzy reduced orderobserver for solving the problem of unbalance in magnetic bearing systems. Nonlinearmodel of magnetic bearing with unbalance is very complicated and coupling betweenvarious states cannot be neglected. With classical methods no one can eliminatedisturbances without linearization of the system and neglecting some terms from thenonlinear model. In this paper ANFIS is used to acquire desired membership functionsof the fuzzy rules for reduced order observer to achieve rejection of unbalance.Simulation results show that fuzzy observer can eliminate the effect of unbalance at anyrotational speed.
https://amme.journals.ekb.eg/article_41373_f67d8d3701fc219192173528ff6d3e33.pdf
2006-05-01
573
587
10.21608/amme.2006.41373
ANFIS
disturbance rejection
gain scheduling
magnetic bearing
and reduced order observer
El Tantawie,
A.
1
Lecturer Mech. Eng. Dept. H.T.I.
AUTHOR
EL Soaly,
E.
2
Prof. Mech. Eng. Dept. H.T.I.
AUTHOR
Hassan,
S.
3
Prof. Aerospace. Dept. Faculty of Engineering, Cairo University.
AUTHOR
ORIGINAL_ARTICLE
SMART FLUID DAMPER MODELS APPLIED TO VEHICLES VIBRATION CONTROL
ABSTRACTElectro-and magneto-rheological fluids are smart, synthetic fluids changing theirviscosity from liquid to semi-solid state within milliseconds if a sufficient strongelectric or magnetic field is applied. When used in suitable devices, they offer theinnovative potential of very fast; adaptively interface between mechanical devicesand electronic control units. This paper gives an overview on the basic properties ofelectro and magneto-rheological fluids and discusses various phenomenologicalmodels for rheological fluid dampers in vibratory systems. The dynamic response ofa quarter-car model with MR- suspension damper is introduced and compared withone uses a conventional viscous damper.
https://amme.journals.ekb.eg/article_41376_de25a1208b0bf81070312f8c93792c0d.pdf
2006-05-01
588
606
10.21608/amme.2006.41376
Electro-and Magneto-Rheological fluid devices
Phenomenological models
Numerical simulation
Passive suspension
El-Demerdash
S.
1
Prof. Automotive and Tractors Engineering Dept.
AUTHOR
El-Butch
A.
2
Asso. Prof., Mechanical Design Dept.
AUTHOR
Rabieh
E.
3
Asso. Prof., Mechanical Design Dept.
AUTHOR
El kafafy
M.
4
Post Graduated Student.
AUTHOR
ORIGINAL_ARTICLE
AN EXPERIMENTAL INVESTIGATION OF HYDRODYNAMIC DAMPING DUE TO BAFFLE ARRANGEMENTS IN A RECTANGULAR TANK
ABSTRACTThe present work is concerned with an experimental study of the hydrodynamicdamping provided by using vertical baffles in partially filled rectangular tanks. Thedamping ratio in a rectangular tank is evaluated for different vertical baffledimensions, shapes, numbers and arrangements. A test rig for a carrying rectangulartank system is designed and constructed to measure the transient responses in timedomain. The baffles are fitted to attenuate the lateral motion of the liquid slosh. Lowerand upper mounted vertical baffles of different heights and numbers are tested.Lower mounted vertical baffles with holes of different sizes and numbers areconsidered. Finally, the effect of a combination between upper, lower and holedvertical baffles on the damping is investigated. The results show that the size andlocation of the vertical baffles significantly influence the hydrodynamic damping. Ingeneral, the damping ratio increases as the lower mounted baffle is close to the liquidfree surface and the center of the tank. Increasing the baffle numbers increases thedamping ratio. The upper mounted vertical baffles are more suitable for chargeabletank. The twin side upper mounted baffles and centre holed Lower mounted bafflearrangements give a maximum damping ratio.
https://amme.journals.ekb.eg/article_41378_f28ed7877d035d98d203f53268ce2100.pdf
2006-05-01
607
623
10.21608/amme.2006.41378
baffles
Rectangular tank
Slosh
Younes
F.
1
Assistant Lecturer, Mechanical Design Dept., Faculty of engineering, Mataria, Helwan University.
AUTHOR
Younes
K.
2
Professor, Mechanical Design Dept., Faculty of engineering, Mataria, Helwan University.
AUTHOR
El-Maddah
M.
3
Professor, Modern Academy for Engineering and Technology, Maadi.
AUTHOR
Ibrahim
M.
4
Professor, Automotive Engineering Dept., Faculty of Engineering, Mataria. Cairo, Egypt.
AUTHOR
El-Dannanh
H.
5
Associate Professor Mechanical Design Dept., Faculty of engineering, Mataria, Helwan University.
AUTHOR
ORIGINAL_ARTICLE
TORSIONAL DYNAMIC OPTIMIZATION OF WIND POWER GENERATORS
ABSTRACTThe present paper develops an appropriate optimization model for placingfrequencies of a typical wind rotor/tower structure in free torsional motion. The aim isto avoid large amplitudes caused by the yawing-induced vibrations in the case ofhorizontal-axis machines or rotational motion of the blades about the tower axis incase of vertical-axis machines. This can be a major cause of fatigue failure and mightseverely damage the whole structure of the wind generator. The mathematicalformulation considers a single pole tower configuration having thin-walled circularcross section with constant taper along the tower height. The nacelle/rotorcombination is modeled as a rigid mass elastically supported at the top of the towerby the torsional spring of the yawing mechanism. The resulting governing differentialequation of motion is solved analytically by transforming it into a standard form ofBessel’s equation, which leads to the necessary exact solutions for the frequenciesand mode shapes. Several cases of study are examined for different values of theyawing stiffness and damping parameters by considering both conditions of lockedand unlocked yawing mechanism. Useful design charts are developed for placing thefrequencies at their needed target values with no penalty of increasing the totalstructural weight of the system. In all, the developed model guarantees fullseparation of the system frequencies from the critical exciting torsional frequenciesby the appropriate choice of the optimization design parameters.
https://amme.journals.ekb.eg/article_41380_80adacca0932a5e5cba94d9f174187b2.pdf
2006-05-01
625
642
10.21608/amme.2006.41380
Structural dynamics
Design optimization
Wind Turbines
KARAM
MAALAWI
1
Associate professor, Dpt. Of Mechanical Engineering, National Research Center, Dokki, Cairo, Egypt.
AUTHOR
ORIGINAL_ARTICLE
Fault monitoring in complex dynamic system by utilization statistical analysis technique
ABSTRACT:
Vibration monitoring is widely accepted defects in rotating machinery components using traditional diagnostic analysis to match spectral line with known defect frequencies that are characteristics of the affected machinery components. The present work highlights the accurate fault defect, higher order spectrum analysis (HOSA) in rotating machinery and focus on the rare failure due nonlinearity based on compound mode which cannot appear in traditional diagnostics. And compare the results of the traditional linear spectra analysis in the case of fault monitoring of experimental tests carried out on eccentric cam in a specially designed cam dynamic test fixture. The test performed on the complex system, the cam is excited by impact hammer. An accelerometer is used to measure the acceleration response for different manufacturing routes of cams. The ambient excitation and the system response are used to compute a number of quantities for the system under two operating conditions of surface finish. In particular the power spectrum density (PSD), the frequency response function (FRF), the second order coherence function and the third order system bicoherence are measured and calculated. The measurements are compared and the results are discussed. The results shows that the nonlinearity due to compound mode cannot appear in linear spectra analysis. The results shows also that the traditional linear spectra analysis is of limited value in monitoring faults.
https://amme.journals.ekb.eg/article_41681_b70c0bba046d2f8e2f3dcde3e7b9444b.pdf
2006-05-01
643
658
10.21608/amme.2006.41681
Vibration monitoring
Feature selection of damage
Detect nonlinear behavior and high order spectrum analysis
Gomaa
R.
1
Assistant Professor, Department of Production Engineering and Mechanical Design, Faculty of engineering, Shebin El-Kom, Egypt.
AUTHOR
ORIGINAL_ARTICLE
IMPROVEMENT OF TRACTOR SEMITRAILER STABILITY DURING SEVERE MANEUVER AT HIGH SPEED
ABSTRACTThis paper presents a new control strategy called "Semitrailer Differential BrakingTechnique (SDBT)" to improve the dynamic stability of 2 axle tractor combined with 3axle semitrailer equipped with a standard antilock braking system (ABS) duringevasive maneuver at high speed. A Matlab Simulink model constructed to study thedynamic stability under different driving conditions; brake sequence, driver input,steering response, road type, and loading condition. The new concept based onmonitoring of the yaw rate difference between the tractor and semitrailer, andapplying differential braking on the semitrailer at certain articulation rate threshold.The results show improving of the handling performance of the combination againstrollover and jackknifing during evasive maneuver at high speed.
https://amme.journals.ekb.eg/article_41682_bd431e8f98089c83588e86fe5b82eace.pdf
2006-05-01
659
679
10.21608/amme.2006.41682
Jackknifing
handling performance
stability control
semitrailers
Articulation Rate
heavy vehicles
fifth wheel
semitrailer differential braking technique
Yaw rate
Elhemly
A.
1
PhD. Application, Faculty of Engineering, Cairo University.
AUTHOR
Zeyada
Y.
2
Associated professor, Dpt. of Mech. Design and Production, Cairo University.
AUTHOR
Fayed
A.
3
Associated professor, Mechanical Engineering Branch, Military Technical Collage.
AUTHOR
ORIGINAL_ARTICLE
DYNAMIC IMPACT PROBLEMS: MODELING AND ANALYSIS
ABSTRACTSolid mechanics investigators gave the dynamics of bodies in impact special interestlong time ago. Many approaches were developed to solve this problem since F.Neumann (1885). Reviewing these various approaches revealed that the impact bodyusually regarded as a system possessing one degree of freedom and the aim is to seekthe configuration of maximum compression when the body starts to achieveinstantaneous equilibrium. This paper is aimed to model the impacted body as a systempossessing multi degrees of freedom by using the finite element method. The normaland oblique impacts are discussed taking into consideration the neighborhood area ofthe instantaneous impact point is smooth or rough. The effect of the number of elasticmodes of vibration on the impact response is considered.
https://amme.journals.ekb.eg/article_41683_7ed8dcb06a6dbfe34c354896a80b98ce.pdf
2006-05-01
679
696
10.21608/amme.2006.41683
Elhady
M.
1
Department of Space Science, National Authority of Remote Sensing and space Science, Cairo, Egypt.
AUTHOR
ORIGINAL_ARTICLE
CRACK DETECTION IN BARS WITH LONGITUDINAL CRACK USING VIBRATION MEASURING TECHNIQUE
ABSTRACTIn this paper the dynamic behavior of a cylindrical bar with longitudinal crack as anew case of crack geometry is investigated. The bar is bounded and excited in waywhich permits only torsional vibration of the bar. This work is based on crack inducedby the manufacturing processes not due to applied load. The dynamic analysis of thecracked bar is based on the investigation of the measured transient response in timeand frequency domains beside its modal parameters. Experiments are carried out intwo different specimens of the bar providing that their mechanical properties anddimension are kept identical. The first specimen of the bar is uncracked while thesecond one has a longitudinal crack along its whole length. The bar is excited with itsfirst torsional mode and the measured signals are analyzed using (FFT) analysis. Afinite element model has been made using ANSYS software to simulate theuncracked bar. Modal, transient and harmonic analysis are made to validate theexperimental work. The finite element prediction of the dynamic response and thefundamental natural frequency were in good agreement with the experimentalresults. This work suggests a simple method for crack detection in beams.
https://amme.journals.ekb.eg/article_41684_7625c370830cdad3de16cc73d38aa813.pdf
2006-05-01
697
717
10.21608/amme.2006.41684
Crack Detection
torsional dynamic response
cracked bar
Bennaya
M.
1
Egyptian Armed Forces.
AUTHOR
Mahgoub
M.
2
Egyptian Armed Forces.
AUTHOR
Sherif
A.
3
Higher Institute of Technology-10th of Ramadan.
AUTHOR
ORIGINAL_ARTICLE
A CRACK PATH-BASED MODEL TO ASSESS MICROSTRUCTURE INCLUSIONS RANDOMNESS
ABSTRACT:
Discussed are the two main phenomena often observed in engineering materials prior to its fracture; namely dislocation-based strain hardening and the crack governing factor to steer its direction of propagation. The study investigates the micro displacements of these two mechanisms as monitored in a soft matrix full of hard obstacles (constraints). Based on a marked similarity with an artificial intelligence method called Uphill Climbing, a cellular model is so constructed that relevant formulas of plane strain analysis are properly included. In the model, the magnitude and direction of each successive micro displacement are optimized with reference to a globally updated potential objective and a locally selected stressed spots. It is found that for a randomly uniform obstacle distribution, low values of mean obstacle density lead to a direction-independent resistance against defects′ micro displacements. As obstacle density increases, such a resistance shows a direction trend. Depending on the dislocation hardening history, the 100% full loading results in several independent segments of crack paths that may either finally meet or distantly lock apart, in which cases the fractured surfaces reflect relevant distinct zones.
https://amme.journals.ekb.eg/article_41686_79cd070cb82ef74f9109460b47e335d4.pdf
2006-05-01
1
14
10.21608/amme.2006.41686
Dislocation Flows
Irregular Crack Propagation
Locked Crack
artificial intelligence
Uphill Climbing Technique
MOHAMED
S.
1
AUTHOR
ORIGINAL_ARTICLE
FATIGUE RESISTANCE OF MAGNESIUM ALLOY AZ 91D AT HIGH-FREQUENCY CYCLE LOADING.
ABSTRACT:
The presented paper brings the result of Mg-alloy AZ 91D metallographic and fractographic fracture surfaces analysis, fatigue crack propagation and fatigue life measured at high-frequency cyclic loading. Microstructure of magnesium alloy AZ 91D specimens after thermal processing is created by uniform polyhedric grains of phase δ. At some places, within the grain boundaries there has been found the presence of small amount of discontinual precipitates consisting of fine lamellas of phase Y(electron compound Al12Mg17) in matrix of δ phase. Experimentally measured values of the fatigue resistance of alloy AZ 91D has been caused, first of all, by the presence of cast defects (micropipes, structural heterogeneities). The occurrence of these defects, their character, size, orientation, amount and location on the surface and in subsurface layers influenced in a negative way and to a various degree the strength the fatigue resistance of the studied alloy. The fatigue behavior and character of the fatigue fracture of the alloy AZ 91D are highly dependent on structural factors and on the level of technical perfection of their production, the character of the fracture surface morphology depended on the size of stress amplitude a to a considerable degree, due to strong structural heterogeneity and occurrence of large amount of cast defects (first of all, usually appearing microscopic cavities) it was not possible to show really the influence of the amplitude size of the applied strain on the initiation and micro-mechanism of fatigue failure development.
https://amme.journals.ekb.eg/article_41694_35255789fd938ff70bd448666c3c40b1.pdf
2006-05-01
15
21
10.21608/amme.2006.41694
magnesium alloy
High-frequency cyclic loading
Fatigue crack
Gigacycle mode of loading
KUFFOVA
M.
1
Dipl. Eng., PhD., Dpt. of Mechanical Engineering, Academy of the Armed Forces of Gen. M. R. Stefanik, Liptovsky Mikulas, Slovakia.
AUTHOR
ORIGINAL_ARTICLE
FINE GRAINED 6061 ALUMINUM ALLOY SHEETS PRODUCED BY ACCUMULATIVE ROLL- BOUNDING (ARB) PROCESS.
ABSTRACT:
In the present study the accumulative roll-bonding (ARB) process was applied to the 6061 alloy sheets and to clarify the evolution of the microstructures of produced sheets. The accumulative roll-bonding (ARB) process is intense plastic straining process. In the ARB process, a strip is neatly placed on top of another strip. The two layers of material are joined together by rolling (reduction degree of 50%) like a roll-bonding process. Then, the length of rolled material is cut into two halves. These two halves are again stacked and roll-bonded. The whole process is repeated again and again. By the ARB process, Avery fine grain structure of 6061 Al alloy, less than three micron, was formed and the material was strengthened dramatically.
https://amme.journals.ekb.eg/article_41700_81c21b8a642e275fc965ce4ba1cbba9c.pdf
2006-05-01
22
34
10.21608/amme.2006.41700
Accumulative Roll Bonding (ARB) process
Roll Bonding
Solid State Welding
Grain Refining
6061 Aluminum Alloy
EL SEAIDY
I.
1
Assistance teacher, ETRR-2, Nuclear Research Center, Atomic Energy Authority, Inshas 13759, Cairo, Egypt.
AUTHOR
IBRAHIM
M.
2
Professor, Metallurgy Department, Faculty of Engineering, Cairo University, Giza, Egypt.
AUTHOR
GHONEIM
M.
3
Professor, Metallurgy Department, Nuclear Research Center, Atomic Energy Authority, ETRR-2, Inshas 13759, Cairo, Egypt.
AUTHOR
ORIGINAL_ARTICLE
THE MECHANICAL BEHAVIOUR OF RECYCLED HIGH DENSITY POLYETHYLENE
ABSTRACT:
In last few years with the increasing use of polymeric materials the disposal of the used material became a serious problem. As polyethylene is one of the common used polymers in many applications it represents a significant amount of the total municipal waste of thermoplastic materials. Thus recycling process of polyethylene is a subject which needs more investigation of the mechanical properties was carried out on virgin and recycled /virgin high density polyethylene (HDPE) to study the effect of three successive generations of HDPE as well as of the amount of recycled material added to the virgin one on the density, tensile, impact, and creep properties. The results showed that with recycling the HDPE three times, the density as well as the modulus of elasticity, the percentage elongation, the impact strength, and the recovery percentage of the HDPE decrease while the tensile strength increasing the recycled to virgin ratio of HDPE the density, the impact strength, and the recovery percentage increase while the modulus of elasticity, the percentage elongation, and the tensile strength remains almost constant.
https://amme.journals.ekb.eg/article_41701_86a40e6fba0080c2a3ff8143289cdb42.pdf
2006-05-01
35
50
10.21608/amme.2006.41701
polyethylene
recycling
recovery
Mechanical Properties
and moulding
Ali
A.
1
Egyptian Armed Forces.
AUTHOR
Abo El-Khair
S.
2
Egyptian Armed Forces.
AUTHOR
ORIGINAL_ARTICLE
THE QUALITY OF AL-SI CASTING OF L SECTION USING WILLIAM′S CORE AND ELLIPTICAL AND SPHERICAL RISERS
ABSTRACT:
The transformation from the liquid to the solid state is accompanied by the volumetric shrinkage that occurs during solidification. Risers are in the production of castings for the purpose of providing molten metal for the solidifying and shrinking casting. Riser design in sand castings requires, at a minimum, that the riser solidifying after the casting. The most important aluminum foundry alloys are based on the Al-Si system, especially the hypo-eutectic alloys with compositions ranging from 7 to 11 wt.% silicon. In the present work blind riser of elliptical and spherical shapes were used in the casting of “L” section of different sizes. The ratio between the casting modulus to the riser modulus was studied. William′s core was also used to study the effect of applying pressure on the quality of Al-Si alloy. The results showed that the position of the riser and the pouring gate influence significantly the soundness of Al-Si castings. The casting of “L” section with large size showed sound casting when elliptical riser is used, and when the pouring gate was placed beside the riser and relative modulus was 1.5. Also the proportion of feed metal available from the feeder which meets the modulus % C was 9.7. Sound casting for “L” section of small size was observed when the spherical riser with relative modulus 1.0 was used and the % C was 8.4. Using the spherical riser in this case leads to save the material by 20%.
https://amme.journals.ekb.eg/article_41800_26729b5fb823dd04d8e4f576bd4821c5.pdf
2006-05-01
51
68
10.21608/amme.2006.41800
Shrinking Cavity
elliptical riser
Spherical riser
pouring gate
casting modulus
IBRAHIM
M.
1
Prof. M.IBRAHIM, Mechanical department, Faculty of Engineering, Banha University.
AUTHOR
ISKANDER
A.
2
Assoc. Prof, B.A.ALSKANDER, Academy of Specialized Studied - Technology department, Nasr City, Cairo.
AUTHOR
MOHIE
M.
3
Eng.M.K. Mohie. Academy of Specialized Studied - Technology department, Nasr City, Cairo.
AUTHOR
ORIGINAL_ARTICLE
WINDING ANGLE EFFECT ON FRATURE BEHAVIOUR OF COMPOSITE TUBES UNDER DIFFERENT LOADING CONDITIONS
ABSTRACT:
Glass-fibers/plastic tubes are increasingly used in industrial environments where their strength, low weight, and corrosion resistance make them competitive with other materials. Filament winding process provides a mean of producing fiber-reinforced tubes in which the direction of fibers is closely controlled to give very high strength in preferred direction. The aim of this work is to investigate the effect of winding angle and number of layers on burst behavior of filament wound tubes manufactured by circumferential winding process. The tubes were tested to failure under longitudinal, hoop, and biaxial loading. Filament wound tubes was fabricated using E-glass-fibers/polyester at winding angles ranging from 35° to 85° and number of layers 8 and 14. The results of internal pressure hoop test showed a significant rise in the hoop burst stress and initial modulus with increasing winding angle, while the strain to failure decreased. The high winding angle tubes, 60° and above, failed by catastrophic fiber fracture. Tubes with lower winding angle were characterized by “Initial failure” associated by longitudinal resin cracking that lead to a subsequent degradation in tube modulus. The uses of rubber liner during tests lead to a significant increase in maximum stress and strain to failure. The elastic properties were measured in longitudinal and hoop directions and a stress/strain response was obtained for each tube. The results were found to be consistence with the current theories for filament wound angle ply composites.
https://amme.journals.ekb.eg/article_41817_5e569fff7a2c929857f78f8be35e13ee.pdf
2006-05-01
69
80
10.21608/amme.2006.41817
El-Wahab
M.
1
AUTHOR
El-Soaly
E.
2
AUTHOR
El-Kader
S.
3
AUTHOR
Daken
H.
4
AUTHOR
ORIGINAL_ARTICLE
STUDY OF THE MECHANICAL AND METALLOGRAPHIC PROPERTIES OF CARBON-ALUMINA COATED IRON PRODUCED BY IMPULSE PLASMA DEPOSITION
ABSTRACT: Carbon-Alumina films were deposited on the surface of iron substrate at room temperature using impulse plasma deposition (IPD) method. The plasma beam was generated from a coaxial plasma gun. The pulsed plasma mainly consists of two kinds of ions: working gas ions and inner electrode ions. Acetylene gas (C2H2) was used as a source of carbon atoms. While the inner electrode was the source of Aluminum present in the deposited Aluminum phase. Coatings were produced on iron substrate by a number of plasma pulses (50-200) from 15.42 μ F capacitor bank at 13.5 kV discharging voltage. The plasma coaxial gun parameters were determined. The microstructure of the deposited Carbon-Alumina films were observed using scanning electron microscope (SEM) while the surface micro hardness was measured using Vickers micro-hardness testing machine. The deposited film thickness was measured using electronic coating thickness tester. The surface micro-hardness increased by 65% at 200 plasma pulses from its value for untreated iron substrate. The film thickness increases with the number of plasma pulses with an average deposition rate of 30nm/pulse.
https://amme.journals.ekb.eg/article_41842_17850d1364bbf66ae587b6502811784d.pdf
2006-05-01
81
91
10.21608/amme.2006.41842
IPD method
Carbon-Alumina
Plasma Coaxial Gun
RASHAD
M.
1
Egyptian Armed Forces.
AUTHOR
MASOUD
M.
2
Atomic Energy Authority, Cairo, Egypt.
AUTHOR
HASSAN
F.
3
Egyptian Armed Forces.
AUTHOR
OSMAN
M.
4
Egyptian Armed Forces.
AUTHOR
ORIGINAL_ARTICLE
DESIGN ALTERNATIVES FOR A MULTI-STANDARD MACHINE
ABSTRACT:
This paper puts forth a suggested concept to design a machine whose standardized parts belongs to a variety of codes. Rewards of adopting such a multi-standard concept are discussed versus the drawbacks of the conventional single-standard concept. In order to overcome relevant huge computations, the study takes advantages of an artificial intelligence scheme called “uphill climbing” embedded with constrained permutations trials. The study ends up with three application findings. First, mixing of even a few standards yields a robust tangible reduction of machines′ overall weight. Second, the more the number of mixed standards in a machine, the lighter is the machine′s weight. Third, in the cases that both the machine′s manufacturer and its user undergo some parts shortage, a set of reliable alternative designs become readily accessible.
https://amme.journals.ekb.eg/article_42144_33f386c710d13f1ded3ec828558fd52e.pdf
2006-05-01
410
420
10.21608/amme.2006.42144
Mohamed
S.
1
Arab Academy for Sciences and Technology, Egypt.
AUTHOR
ORIGINAL_ARTICLE
DESIGN AND MANUFACTURING OF NEW UNWEIGHING SYSTEM.
ABSTRACT:
Significant advanced in neurological research producing growing evidence that spinal cord neuron have a capacity for memory independent from the brain has promoted the rehabilitation using unweighing systems which enables partial weight bearing therapy and conducted with the assurance of patients comfort and safety. The objective of this paper is to design and manufacture of a device that helps patients where weight bearing is to be carefully regulated during walking. The advice would be able to perform partial unweighing and tell the physician how much weight we are reliving from the patient in a simple reliable and easy to use mechanism. The advice consists of large metal frame with a suspended rope from its center. The rope connected to harness and vest to support the patient as he walks on a treadmill. The inside of the metal frame is a set of pulleys, Power screws, bearings and two single stage bevel gear reducer, one at each side. The design of the whole mechanism is done using inventor soft ware package while the outside frame is designed and checked by the help of SAP2000 soft ware package followed by real manufacturing of it. The device is tested on a real patient and it helps in their quick recovery.
https://amme.journals.ekb.eg/article_42154_84928d78117403d36ca37ed3580b4213.pdf
2006-05-01
421
431
10.21608/amme.2006.42154
Omer
A.
1
Egyptian Armed Forces.
AUTHOR
Elshaer
I.
2
Egyptian Armed Forces.
AUTHOR
ORIGINAL_ARTICLE
METHODOLOGY OF OBTAINING STRUCTURAL MODEL OVER A MONOCOQUE CLOSED INTEGRAL SEDAN CAR BODY STRUCTURE
ABSTRACTThe car body structure is a highly redundant structure with more than one load path andthe sharing of the load is a function of the component relative stiffness. In static stressanalysis, only the loads that cause elastic strains and stresses in the structure arestudied in such a way that there is no yielding of the material or joint failure results.Practical experience suggests that a vehicle structure which is strong enough to endurethe maximum dynamic loads, which occur sporadically, will also have sufficientresistance against repeated dynamic forces at less than their average value (fatigueloading), then the key factor in the design analysis process is the determination of ‘TheDynamic Load Coefficient’ which can be used in the static analysis. [1]The structural stress analysis of the car body is carried out by the discussion of:1- The concept of the load-bearing structure.2- The determination of the input loads.3- Implementation of different theories for the static of the structure and the strength ofthe body and its joints.The first part of the structural stress analysis is the study of the load-bearing structure.The general description of the car body structural components under consideration inthis paper and its three subassemblies are discussed followed by the descriptions of thestructural model idealization.
https://amme.journals.ekb.eg/article_42156_321896418bfaae94ce60bd0aea7b41e0.pdf
2006-05-01
432
445
10.21608/amme.2006.42156
Monocoque
Car Body Structural Analysis
Finite Element Analysis
Thin-walled structure
Optimization Analysis
Ahmed
K.
1
Egyptian Armed Forces.
AUTHOR
Mohamed
M.
2
Egyptian Armed Forces.
AUTHOR
Metwally
M.
3
Egyptian Armed Forces.
AUTHOR
Mokhtar
E.
4
Arab Industrialization Authorization, Cairo, Egypt.
AUTHOR
ORIGINAL_ARTICLE
SEPARATION AND IDENTIFICATION OF SIMULATED DIESEL ENGINE NOISE USING INDEPENDENT COMPONENTANALYSIS AND TIME-FREQUENCYANALYSIS
ABSTRACT:
In this paper the separation and identification of diesel engine noise is investigated using independent component analysis (ICA) and time frequency analysis (TFA). The separation and identification of engine real noise is important for noise reduction and faults diagnosis. This study can be considered as a guide for engine real noise separation and identification. A diesel engine noise is mathematically modeled and a single cylinder engine noise is simulated. The simulated noise sources are exhaust valve close, inlet valve close inlet valve close, fuel injection, combustion, piston slap, exhaust valve open and inlet valve open. The individual simulated engine noise sources signals are considered as acquired signals by seven channels microphone array. The mixed sources signals are separated using ICA. The separated independent components (ICs) are analyzed by short time Fourier transform (STFT) in time-frequency plane. The time is then converted to crank angle in order to identify engine noise sources. As predicted, the results show that the separated engine noise sources well correlated with the engine design specifications.
https://amme.journals.ekb.eg/article_42174_70a274d402269a56aab80bed920a5e7e.pdf
2006-05-01
264
281
10.21608/amme.2006.42174
Diesel engine noise
blind source separation
independent component analysis
short time Fourier transform and time-frequency analysis
Badawi
B.
1
PhD Postgraduate candidate, Dept. of Mech. Power and Energy, Military Technical Collage, Cairo, Egypt.
AUTHOR
A.
Elmaihy
2
Egyptian Armed Forces.
AUTHOR
Samy
S.
3
Egyptian Armed Forces.
AUTHOR
Shahin
A.
4
Assistant Prof., Faculty of Engineering, Modern University of Engineering and Technology, Cairo, Egypt.
AUTHOR
Mohamed
I.
5
Egyptian Armed Forces.
AUTHOR
ORIGINAL_ARTICLE
DIESEL ENGINE MISFIRE DETECTION UTILIZING TIME-FREQUENCY ANALYSIS OF MEASURED ENGINE VIBRATION
ABSTRACT:
This paper describes the detection of diesel engine cylinder misfire utilizing the engine vibration measurements. The proposed technique depends on time-frequency analysis (TFA) of the measured engine surface vibration. The combustion induced vibration and noise of engine is mathematically modeled and the vibration signals are simulated for fired and misfired engine. Both simulated and measured vibration signals for fired and misfired are analyzed by fast Fourier transform (FFT) in frequency domain to identify the signals′ frequencies. Then, they are analyzed in time-frequency plane. To investigate the engine fire and misfired according to firing order of the engine cylinders, the time-frequency plane is converted to the corresponding crank angle-frequency one. From crank angle-frequency analysis of the engine vibration the engine misfire is detected from the measured vibration signal as well as from the simulated one. The experimental results show that the engine misfire can be detected by time-frequency analysis of measured engine surface vibration.
https://amme.journals.ekb.eg/article_42188_cdf8bdd4cd67701c31426aa7b5c39ac5.pdf
2006-05-01
282
297
10.21608/amme.2006.42188
Diesel Engine
engine fire
engine misfire
time-frequency analysis and vibration
Badawi
B.
1
PhD Postgraduate candidate, Dept. of Mech. Power and Energy, Military Technical Collage, Cairo, Egypt.
AUTHOR
A.
Elmaihy
2
Egyptian Armed Forces.
AUTHOR
Samy
S.
3
Egyptian Armed Forces.
AUTHOR
Shahin
A.
4
Assistant Prof., Faculty of Engineering, Modern University of Engineering and Technology, Cairo, Egypt.
AUTHOR
Mohamed
I.
5
Egyptian Armed Forces.
AUTHOR
ORIGINAL_ARTICLE
EFFECT OF PIPE INCLINATION AND ADDING FINES ON SLURRY TRANSPORT OF COARSE PARTICLES.
ABSTRACT:
This work presents results for slurry transport systems which combines the effect of adding fines to the carrier and varying pipe inclination angle. Results showed that adding fines sometimes reduces pressure head-loss when the pipes starts to incline upward. The deposit velocity increases with pipe inclination till 30° and then decreases. The deposit velocity was found to vary remarkably when fine particles are added to the carrier fluid.
https://amme.journals.ekb.eg/article_42199_c2ea27ec12ba73b60a2638a06dd6098b.pdf
2006-05-01
298
314
10.21608/amme.2006.42199
Slurry
pipelines
rheology
two-phase
deposit velocity
Fangary
S.
1
Assistant Professor, Mechanical Power Department, Faculty of Engineering, Ain Shams University, Cairo, Egypt. Corresponding author.
AUTHOR
Mahmoud
A.
2
Professor, Mechanical Power Department, Faculty of Engineering, Ain Shams University, Cairo, Egypt.
AUTHOR
ORIGINAL_ARTICLE
INVESTIGATION OF STATIC AND DYNAMIC BEHAVIOUR OF PREESURE COMPENSATED VARIABLE DISPLACEMENT SWASH PLATE AXAL PISTON PUMP
ABSTRACT: This paper is a part of study, conducted to improve the control capabilities of a pressure compensated pump, by implementation of an electrohydraulic controller. This part of was dedicated to investigate the static and dynamic behavior of an axial piston pump of swash plate type. The studied pump is of variable displacement type. It is equipped with a hydro mechanical controlled (pressure compensator). This controlled keeps the pump displacement maximum if the pressure is less than certain limiting value. When the pump exit pressure exceeds this limit, the controlled reduces the pump displacement gradually until the real pump flow becomes null. The study starts by deducing detailed mathematical model describing the pump together with its hydro mechanical controller. The deducing mathematical model is used to develop a computer simulation program for the studied system using (SIMULINK). The steady state pump flow characteristics were evaluated experimentally and used to validate the simulation results. The comparison of the theoretical and experimental results of the pump flow characteristic showed good agreement between them. The simulation program was used to investigate the dynamic behavior of the pump equipped with its pressure compensator. This class of pump controlled produces unique control law. Any modification of the control law requires major modification of the controlled design.
https://amme.journals.ekb.eg/article_42235_248e6d056101a5286d330d96cdf3edae.pdf
2006-05-01
315
333
10.21608/amme.2006.42235
Axial
piston
pump
swash plate
variable displacement
pressure compensator
static
Dynamic
Transient
Tamer
SALEH
1
Graduate student, Dept. Of Aircraft Mechanics, Egyptian Armed Forces.
AUTHOR
M.
RABIE
2
Assistant Professor, Mechatronics Dept., Higher Tech. Institute, 10th of Ramadan City.
AUTHOR
S.
ABDOU
3
Professor, Industrial Engineering Dept., Modern Academy For Eng.&Tech., Cairo, Egypt.
AUTHOR
ORIGINAL_ARTICLE
DYNAMIC PERFORMANCE OF AN ELECTROHYDRAULIC SERVO ACTUATOR WITH CONTACTLESS CONTROLLED SPOOL
ABSTRACT:
This paper deals with the analysis of dynamic behavior of an electrohydraulic proportional actuator. The studied system consists of an electromagnetic proportional solenoid, a hydraulic cylinder and a directional control valve incorporating a non-conventional hydraulic amplifier. The spool of the directional control valve is driven by the pressure force developed by the built-in hydraulic amplifier. The peculiarity of the spool-solenoid interaction, forces the spool to have the same displacement as that of the solenoid core. The solenoid force is only needed to activate the hydraulic amplifies. This leads to the use of a solenoid of small dimensions. The system has been studied theoretically by deducing a nonlinear mathematical model, and developing a computer simulation program.
The used solenoid is of the stroke controlled type. The steady state current-displacement relation has been measured and considered in the simulation program. The transient response of the solenoid has been measured experimentally and used to validate the simulation program. The proportional actuator has been studied in a closed loop control system. A PIC controlled has been designed to improve the closed loop dynamics. The performance of the system has been studied theoretically on the base of the developed simulation program.
https://amme.journals.ekb.eg/article_42245_65b112c2338c41c16801031f7c77b26c.pdf
2006-05-01
334
351
10.21608/amme.2006.42245
electrohydraulic
proportional
Electromagnetic
Solenoid
valve
Actuator
Spool
PID
Simulation
Closed Loop
M.
Metwally
1
Ph.D.Applicant, Egyptian Armed Forces.
AUTHOR
G.
Rabie
2
Professor, Modern Academy for Engineering and Technology.
AUTHOR
N.
Girgis
3
Professor, Military Technical Collage.
AUTHOR
I.
Saleh
4
Professor, Military Technical Collage.
AUTHOR
ORIGINAL_ARTICLE
HEAT TRANSFER ENHANCEMENT IN PIPE FLOW WITH DOWNSTREAM PULSATION
ABSTRACT:
Experiments were carried out to investigate the heat transfer characteristics for turbulent flow through pipes with downstream pulsation. Measurements were conducted in a horizontal brass pipe of 40 mm inner diameter and 3000 mm long under uniform heat flux condition, with air as a working fluid. The pulsating frequency was ranged from 45 to 145 Hz and Reynolds number was varied from 27900 to 58900. The results show that an enhancement in heat transfer is obtained for the pulsated flow for different values of both Reynolds number and pulsating frequency. The rate of enhancement decreases as the pulsation frequency increases. The maximum enhancement of the relative average Nusselt number (about 84.5 %) is obtained with Re = 55500 and f = 45 Hz, while the minimum enhancement (about 17%) is obtained at Re =42500 and f = 145 Hz. As Reynolds number increases from 27900 to 35800, the relative average Nusslet number increases and peaks at Reynolds of 35800 and pulsation frequency of 93.3. As Reynolds number increases further from 35800 to 42500, a reduction in the relative average Nusslet number is obtained for the whole studied range of the pulsation frequencies. While as Reynolds number increases further (42500 ≤Re≤ 58900), the relative average Nusselt number increases again with about 84.5% maximum enhancement. The present experimental data for the relative average Nusselt number enhancement ratio were correlated in terms of Reynolds number and the dimensionless frequency.
https://amme.journals.ekb.eg/article_42246_0bbe218739af36905b8d889349b0e30c.pdf
2006-05-01
352
368
10.21608/amme.2006.42246
Pulsating pipe flow
downstream pulsating
flow vibration
pulsation frequency
periodic turbulent pipe flow
A.
El-shamy
1
Mech. Eng. Dept., Shoubra Faculty of Engineering, Banha University.
AUTHOR
R.
Afify
2
Mech. Eng. Dept., Shoubra Faculty of Engineering, Banha University.
AUTHOR
S.
Abdel-Moneim
3
Mech. Eng. Dept., Shoubra Faculty of Engineering, Banha University.
AUTHOR
H.
Refaey
4
MSC Student.
AUTHOR
ORIGINAL_ARTICLE
STUDYING THE PARAMETERS INFLUENCING THE ACCURACY OF ELECTRON BEAM DERILLED HOLES
ABSTRACT:
Electron beam drilling has been widely used in industry. The drilling process is performed when the electron beam is focused with enough energy to melt and vaporize the drilling substrate. The present work introduce the study of the influence of different beam parameters as beam current, focusing current and pulse frequency on the accuracy of the drilled holes in low carbon steel specimens. High speed machining experiments with deflection coil are performed. The produced holes accuracy is evaluated mainly by conicity and circularity
https://amme.journals.ekb.eg/article_42250_657289e099525a6c9accacdc4440ba73.pdf
2006-05-01
202
213
10.21608/amme.2006.42250
electron
Beam
and drilling
ELNAGGAR
M.
1
Egyptian Armed Forces.
AUTHOR
KOHAIL
M.
2
Associate Professor, Faculty of Technology , Workers University, Cairo, Egypt.
AUTHOR
MOUGHITH
S.
3
Egyptian Armed Forces.
AUTHOR
ORIGINAL_ARTICLE
OPTIMIZATION OF IDLE PATH IN DRILLING ON CNC MACHINING CENTRE USING THE GA
ABSTRACTOptimization of the idle time is the objective of the present work which is done byminimizing the idle tool path in drilling on CNC machining centres to improve productivityas a result of reducing the idle path time. The case is formulated as a travelingsalesman problem and is solved using the Genetic Algorithm (GA). The Branch andBound (B&B) optimization method was used for the sake of comparison with the GeneticAlgorithm. The working mechanism of the GA was inspired by the nature which is basedon the evolutionary process of biological organisms. The work is done in three steps,first step is the parameterization of the GA parameters (population size, replacement,crossover and mutation); Second step is the numerical study for the GA validation, forcomparison between the GA and B&B and comparison between the GA and the currentpractice, the third step is the experimental verification of GA results.
https://amme.journals.ekb.eg/article_42253_92c2abff305fdf270f29a429af673b68.pdf
2006-05-01
214
228
10.21608/amme.2006.42253
Idle time
Optimization
Drilling and GA
Abd Elkhalek
M.
1
Egyptian Armed Forces.
AUTHOR
Elhakim
A.
2
Professor, Dpt. Of Production Engineering, Ain Shams University, Cairo, Egypt.
AUTHOR
Wahba
A.
3
Egyptian Armed Forces.
AUTHOR
Moughith
S.
4
Egyptian Armed Forces.
AUTHOR
ORIGINAL_ARTICLE
THE INFLUENCE OF LASER ASSISTED TURNING PARAMETERS ON CUTTING FORCES-NEW APPROACH
ABSTRACT:
Super alloys have high strength at elevated temperatures, which make them very important to various applications. Such materials are usually difficult to machine at room temperature due to excessive tool wear and poor surface finish. Laser-assisted machining (LAM) offers the ability to those materials more efficiently and economically by providing the local heating of the work piece before conventional cutting take place. AISI D2 steel is an important example of these super alloys. The machinability of D2 steel is investigated in this work. This involved the use of crystal laser as heating source together with conventional turning operation. The experimental investigation took into account the cutting forces and tool wear. A comparison between conventional and laser assisted cutting was performed. The effects of variable cutting speed, depth of cut and laser power were investigated. The experimental results showed improvement in cutting conditions and reduction in cutting forces up to 37%.
https://amme.journals.ekb.eg/article_42641_3f9a4ed57dd5a0b25dc2083a58c32b10.pdf
2006-05-01
229
238
10.21608/amme.2006.42641
Laser assisted machining (LAM)
Turning
Nd-YAG laser
and machinability
BAKER
H.
1
Egyptian Armed Forces.
AUTHOR
YOSSEF
F.
2
Egyptian Armed Forces.
AUTHOR
KHOAIL
M.
3
Chief of the Academy for specialized studies, Worker′s University, Cairo, Egypt.
AUTHOR
MOUGHITH
M.
4
Egyptian Armed Forces.
AUTHOR
ORIGINAL_ARTICLE
DETERMINATION OF MACHINING PROCESS FOR ROTATIONAL PARTS USING NEURAL NETWORKS
ABSTRACT:
Computer-Aided Process Planning (CAPP) is the link between CAD and CAM system. CAPP interprets the design information and prescribes appropriate manufacturing processes consistent with the requirements set forth by the designer. Development of a machining process plane is a basic function in manufacturing process. It is a time consuming, and requires significant skills with great deal of experiential knowledge. Process selection is a difficult problem in CAPP since it requires productive CAPP system containing a huge amount of knowledge-facts which limits CAPP capability and flexibility in real manufacturing systems. Al provided some tools for this problem such as artificial neural network (ANN). ANN has the capability of continuous learning and ability to learn arbitrary mappings between input and output spaces. In this paper, a neural network is used for machining process selection in CAPP for cylindrical axis-symmetrical parts. The part features and attributes are the input, and the output is the operation(s) required to produce. Each feature arranged in the same order of logical machining sequences.
https://amme.journals.ekb.eg/article_42650_576a9753aafa621793db2fb2e4cc6c8b.pdf
2006-05-01
239
251
10.21608/amme.2006.42650
ANN
CAPP
CAP
CAM and GUI
EL-AGAMY
S.
1
Egyptian Armed Forces.
AUTHOR
MOHAMMED
AWAD
2
Associate professor, Dept., of Mechanical Engineering, Ain Sham University, Cairo, Egypt.
AUTHOR
ORIGINAL_ARTICLE
A SAFETY PLAN FOR AN INDUSTRIAL PLANT
ABSTRACT:
Discussed is a comprehensive approach to assess environmental safety prior to the controversial decision as to whether an industrial plant to stay operative or shut down. The study suggested that the plant be committed to present update periodic records about its environment-damaging outputs. Such records are then analyzed based on statistical process control charts. A sound safety control is realized via a routine report analysis, followed by appropriately enforced measures. The Control Charts adjust plant safety continuously by comparison with the allowable limits and set the control limits for expected future performance. In addition, three levels of imposed enforcements are involved at safety plan and recommended; being respective penalty fines, temporary halt for a limited-scale correction, and long shut down for an overhaul.
https://amme.journals.ekb.eg/article_42758_499641fe1a3b2c626719d30a484ad92e.pdf
2006-05-01
252
263
10.21608/amme.2006.42758
Statistical Process Control
Safety Control
Environmental Damages
Automobile Assembly plants
Ramadan
R.
1
Egyptian Armed Forces.
AUTHOR
Mohamed
S.
2
Egyptian Armed Forces.
AUTHOR
Assar
A.
3
Egyptian Armed Forces.
AUTHOR
Risha
A.
4
Egyptian Armed Forces.
AUTHOR
ORIGINAL_ARTICLE
DESIGN OF AN EXPLOSIVELY FORMED PENETRATOR CAPABLE OF DEFEATING A SPECIFIC METALLIC TARGET
ABSTRACTDesign of a warhead that forms upon detonation an explosively formed penetrator(EFP) capable of penetrating a specific rolled homogeneous armor (RHA) is the maintheme of this paper. Six different preliminary warhead models have been simulatedusing Autodyn-2D code. The main features of each EFP formed from eachpreliminary model are predicted. The obtained results serve in determining thedesign parameters of the required (refind) warhead model. In addition, the simulatedEFP from the refined warhead model and its penetration into a specific RHA havebeen simulated.Samples of the obtained predicted results by the code for EFPs formed from differentpreliminary and refined warhead models, respectively, are presented with relevantanalysis and discussions. For the refined warhead model, the code predicts that theobtained EFP has a high velocity, high aspect ratio and is capable of penetrating theRHA to the specified thickness. Moreover, the influence of explosive type, its aspectratio and liner material of the refined model on the formed EFP have been predicted.
https://amme.journals.ekb.eg/article_42759_680af07266b84f8206af2bb92099e906.pdf
2006-05-01
446
466
10.21608/amme.2006.42759
Explosively formed penetrator
EFP formation process
penetration mechanics
and high-velocity impact phenomenon
A.
Riad
1
Egyptian Armed Forces.
AUTHOR
M.
Ismail
2
Egyptian Armed Forces.
AUTHOR
E.
Ibrahim
3
National Authority for Military Production, Factory No. 81.
AUTHOR
ORIGINAL_ARTICLE
DYNAMIC BEHAVIOR OF CONTROL VALVES OF A LIQUID ROCKET ENGINE FEEDING SYSTEM
ABSTRACTThis paper presents a part of study conducted to investigate the dynamic behavior ofa rocket propellant rocket engine. The part presented here concerns the modeling,simulation and analysis of the dynamic behavior of the hydraulic control valves of thefeeding system of the studied rocket engine. The study involves the combustionchamber, the gas generator controller, the thrust regulator, and the relief valve. Forthe studied valves, non-linear mathematical models have been deduced and used todevelop computer simulation programs. The study was extended to investigate thestatic and dynamic behaviors of the valves. The study showed that the combustionchamber and gas generator controllers act to produce a feeding fuel pressure equalto the oxidizer pressure. The thrust controller, through regulating the combustionchamber pressure, could keep a fairly constant thrust of the rocket engine. Thedeveloped simulation programs could be used for further investigation of the effect ofthe valves constructional and operational parameters as well as the study of dynamicbehavior of the liquid propellant engine.
https://amme.journals.ekb.eg/article_42760_ea6ffe32205aff4a4fa3bb3dcc223672.pdf
2006-05-01
467
489
10.21608/amme.2006.42760
control
valve
Feeding system
Rocket
engine
liquid
static
Dynamic
Behavior
computer
Simulation
Tamer
MAHMOUD
1
Captain Eng, Egyptian Armed Forces.
AUTHOR
M.
RABIE
2
Professor, Modern Academy for Engineering & Technology, Cairo, Egypt.
AUTHOR
M.
EL-SENBAWI
3
Maj. Gen. (R), Assoc. Professor, Egyptian Armed Forces.
AUTHOR
ORIGINAL_ARTICLE
BALLISTIC RESISTANCE OF FLEXIBLE COMPOSITE AND TEXTILE TARGETS
ABSTRACTAdvanced textile and flexible composites always used for the containment ofhigh-speed fragmentation. The design of body armours, fragmentation curtainsand bomb blankets are end products. In this work, an experimental program isconducted to test a new composite material (3D-weaveTM Kevlar-129/ LINE-Xxs-350), which is a two-component spray-in-place flexible 100% solidsPolyurea/Polyurethane system. Ballistic response of this new composite iscompared to that of (3D-weaveTM) Kevlar-129; the multi-layered targets of thetwo materials are subjected to impact by small arm projectiles with velocity rangeof 300-450 m/s.Moreover, a finite element code based on Newtonian formulation is used topredict the nodal acceleration, velocity and displacement. Forces acting on bothprojectile and target are also predicted. A comparison between experimentalresults and predictions of the code showed general good agreement in the caseof Kevlar targets. The agreement was not quite as good, but still acceptable, forcomposite targets. The average energy absorbed per one layer of the newcomposite and Kevlar targets is determined.Predictions show that the composite targets are generally more efficient than theKevlar targets in defeating impacting projectiles.Finally, post firing examination of Kevlar/line-x targets shows recoverablebehaviour and localized damage after the ballistic impact; this means smalltrauma effect occurred when using this composite as body armour.
https://amme.journals.ekb.eg/article_42761_2ff0ca97b820f66ee36faf36627bae60.pdf
2006-05-01
490
509
10.21608/amme.2006.42761
E.
Elawad
1
Egyptian Armed Forces.
AUTHOR
A.
Fayed
2
Egyptian Armed Forces.
AUTHOR
M.
Abdelkader
3
Prof., Arab Academy for Science, Technology and Maritime Transport.
AUTHOR
ORIGINAL_ARTICLE
MECHANICAL CRITERIA FOR REPORTS TO OPTIMALLY JUMP AND RUN
ABSTRACT:
Various types of functions that robotic can carry out are reviewed, namely; walking, jumping, leaping, hopping, and running. General and specific features for each type of function are discussed towards pinpointing how to design proper paths. A simulation model for the leg linkage by an equivalent spring is proposed. The model′s steady function is achieved by a chain of repeated cycles consisting of compatible segmented paths. Thus, an air segment is a symmetric portion of a whole standard sinusoidal curve. Two numerical case studies reveal that no matter how the legs steadily function, the motion performed by contributing parts has to be based on three considerations. First, the path of the hip joint w.r.t. horizontal ground level should be well stated. Second, the base motion of the supporting leg axle is close to pure rotation about toe/ground adhesion point. Third, the relative contraction of the leg radius expresses the counterpart joints shaping angles and control moments relative to the leg axis. In addition, an appropriate motion designed for the other leg determines the specific type of the intended output function. The output function properly proceeds as long as the other leg is given the accurate time to recover its incoming landing profile.
https://amme.journals.ekb.eg/article_42765_a5b11530d4c8e32a0436c2331cc09445.pdf
2006-05-01
144
164
10.21608/amme.2006.42765
Displacement and speed compatibility
leg linkages
equivalent spring
recovery stage of the landing profile
MOHAMED
S.
1
AUTHOR
ORIGINAL_ARTICLE
THEORETICAL AND EXPERIMENTAL INVESTIGATIONS OF DYNAMIC BEHAVIOR OF AN ELECTRO-HYDRAULIC DIRECTIONAL PROPORTIONAL VALVE
ABSTRACT:
Hydraulic systems are widely used in many fields. Controlling of hydraulic system is carried out through several techniques. Proportional technique is considered one of the important and advanced techniques used to control hydraulic systems. Through this paper a complete model for a directional proportional valve has been built up using SIMULINK program to investigate the dynamic behavior of this class of valves. Experimental work has been conducted to measure the force exerted by the proportional solenoid and the flow rate through the directional proportional valve at different values of solenoid current. The experimental results have been used to validate the simulation program. The dynamic behavior of the electro-hydraulic proportional valve could be investigated using the obtained simulation program.
https://amme.journals.ekb.eg/article_42779_dcab0153a1cbb1279a7e1b0154e24dd0.pdf
2006-05-01
165
177
10.21608/amme.2006.42779
hydraulic
system
valve
directional
proportional
Solenoid
control
Simulation
Molding
investigation
Program
Measurement pressure
Flow rate and SIMLINK
MENSHAWY
M.
1
Egyptian Armed Forces.
AUTHOR
LOTFY
H.
2
Assoc.Prof., Dept.of Mechanical Power & Energy, Egyptian Armed Forces, Egypt.
AUTHOR
ORIGINAL_ARTICLE
CONDITION MONITORING AND CONTROL OF ROLLING MILLS USING ELECTRO-HYDRAULIC SYSTEM
ABSTRACT:
Rolling mills automation System gained prominence in the sixties when the servo system was introduced to the metal forming industry. With the rapid development of the measurement devices, computers and modeling techniques, rolling mill automation has made significant progress in recent years. This paper introduces a new and simple electro-hydraulic system for controlling the rolling mill operation. The proposed system features less number of components, compactness, ease of installation and maintenance. It also exhibits the same rolling mill control performance as obtained when equipped with the conventional control systems. The results of the system simulation are experimentally validated, presented and discussed.
https://amme.journals.ekb.eg/article_42830_edb52d9137197b09e9427ec36bec6b8b.pdf
2006-05-01
178
201
10.21608/amme.2006.42830
Rolling mills
Pressure compensation
electro-hydraulic control
variable pumps
KHALIL
K.
1
Ph.D., Professional Education Instructor, Milwaukee School of engineering, 1025 North Broadway, Milwaukee, WI, 53202-3109, USA.
AUTHOR
DEPING LI
E.
2
Service Manger Eaton Fluid Power, Shanghai Co. Itd., Shanghai, China.
AUTHOR
BHAT
B.
3
Professor, Department of Mechanical & Industrial Engineering, Concordia University Montreal, Canada.
AUTHOR
ORIGINAL_ARTICLE
EXPLORATORY STUDY OF THE BEHAVIOR OF SOME LOCAL AGRICULTURAL RESIDUAL MATERIALS TO BE USED FOR REINFORCING CONSTRUCTION MATERIALS
ABSTRACT:
Although, many agricultural residues had been used in construction applications of the mankind history, but today most of them have become an overburden. Accordingly, burning of their accumulation has become annual habit causing environmental problem combined with the economical losses. Using agricultural residues, with suitable tensile strength, as reinforcing materials for construction materials had shown promising results in literature. In this research an exploratory study is implemented to investigate the physical and mechanical properties of some local materials to be used as reinforced elements for construction materials. As promising natural materials for reinforcing application, some parts of palm trees (e.g. ribs) and water reed stems are chosen for this study. The effect of some limited exposure conditions and protection techniques are also investigated on the tensile behavior of the selected natural materials. The explored materials show promising tensile behavior to be used for reinforcing applications but with low stiffness and durability. Although protection techniques, used in this research, are effective to solve the problem of durability and slippage in the short term, long tensile behavior of the explored residues need to be studied.
https://amme.journals.ekb.eg/article_42834_d939d868b339b45f7b8f53991b9edc7a.pdf
2006-05-01
92
111
10.21608/amme.2006.42834
Sharkawi
M.
1
Assistant Professor, Structural Engineering Department, Faculty of Engineering, Tanta University.
AUTHOR
Showaib
A.
2
Assistant Professor, Mechanical Engineering Department, Faculty of Engineering, Tanta University.
AUTHOR
ORIGINAL_ARTICLE
AN INVESTIGATION OF THE INSERTIONMECHANISM INFLUENCE ON THE OVERALL BEHAVIOR OF THE THREE-DIMENSIONAL AEROSPACE COMPONENTS
ABSTRACT:
In this paper the effect of stitches on the overall behavior of reinforcement structure is investigated by using a finite-element (FE) approach. It is intended to provide an understanding of the basic mechanisms
Which control the reinforced structures. These Structures have been manufactured using a fully automated cell described in pervious publications. Simple uniaxial FE models been developed using the material properties that determined experimentally. Those models have been successfully validated against the experimental tests and used as a basis from which the main models were generated. These latter FE models were employed to conduct a series of analyses on typical I-beams with a variation of stitch patterns and loading conditions. Following a successful validation of the FEA modeling, a parametric study has been conducted on a typical I-beam section with and without stitches to investigate the influence of both stitch position and the loading condition. The investigation has shown that the stitches would reduce the strength of the beam by 8% atmost.
https://amme.journals.ekb.eg/article_43227_940a7c84d332a1ffc881fcddd56ca929.pdf
2006-05-01
1
8
10.21608/amme.2006.43227
Aerospace
Carbon fibre
Robotics
Stitching
resin transfer moulding (RTM)
Automation
Finite Element
Tawfic
M.
1
Department of Mechanical Engineering, Shoubra faculty of Engineering, Banha University.
AUTHOR
ORIGINAL_ARTICLE
AN IMPROVEMENT OF LONGITUDINAL FLYING QUALITY OF HSCT AEROELASTIC AIRCRAFT MODEL USING GPC TECHNIQUE
ABSTRACT:
Applying automation control methods to flexible aircrafts such as High Speed Civil Transport (HSCT) is a way to overcome the difficulties of the coupling between the elastic modes and the rigid body modes. The difficulties involved by sensing the flexure motion and the rigid body motion, which is a source of additional dipoles near the imaginary axis of the s-plan, make the choice of a suitable automatic control method a challenge. To this purpose, this paper intends to investigate the applicability of control strategies, which would be able to compensate the difficulties in stabilizing the aircraft. The proposed method is the so-called Generalized Predictive Control (GPC) technique. After a brief overview of HSCT modeling we recall the basic principles of the GPC. Then, we are interested in the application of this method with four different choices of the tuning parameters. In our study, the objective is not only to stabilize the pitch rate step response, but also to have this response accepted from point of view flying quality by controlling the elevator deflection.
https://amme.journals.ekb.eg/article_43231_bfeab2dff82a695e579dc4d53f9e469f.pdf
2006-05-01
128
143
10.21608/amme.2006.43231
Flying qualities
HSCT
Aero-elasticity
Predictive Control
ABDELHADY
E.
1
Egyptian Armed Forces.
AUTHOR
AMGAD
B.
2
Egyptian Armed Forces.
AUTHOR
GAMAL
E.
3
Cairo University.
AUTHOR