DEVELOPMENT OF CFRE COMPOSITE JOINTS USING MWCNT/E ADHESIVES

Document Type : Original Article

Authors

1 Professors, Dept. of Mechanical Engineering, Faculty of Engineering, King Abdulaziz University, P.O. Box 80204, Jeddah 21589, Saudi Arabia.+

2 On Leave from: Mechanical Design and Production Engineering Department, Faculty of Engineering, Zagazig University, P.O. Box 44519, Zagazig, Egypt. Corresponding author: Tel.: +966553507515; Fax: +96626952181.

3 Professors, Dept. of Mechanical Engineering, Faculty of Engineering, King Abdulaziz University, P.O. Box 80204, Jeddah 21589, Saudi Arabia.

Abstract

ABSTRACT
Epocast 50-A1/946 epoxy was primarily developed for joining and repairing of
composite aircraft structural components. The Epocast epoxy was modified by
ultrasonic dispersion of Multi-Walled Carbon Nanotubes (MWCNTs) with different
weight percentages. Neat epoxy (NE) and the optimum MWCNT weight percentage
are used to fabricate structural adhesive joints (SAJs) with different scarf angles (5o,
10o, 15o, 30o, and 45o) in carbon fiber reinforced epoxy (CFRE) composite
adherends. SAJs with different scarf angles were instrumented by eight strain
gauges to measure the adherend tip strains and bond line strains during tension
tests. The effect of water absorption on the tensile properties of the SAJs with 5o and
10o scarf angles was investigated experimentally. Because the SAJs with 5o scarf
angle have the highest tensile properties, special attention was considered to
investigate their performance under elevated temperature (50, 75 and 100oC) and
fatigue loads. The tensile properties of the MWCNT/E-SAJs showed significant
improvements compared to the neat epoxy-SAJs. Crack initiation and propagation
were detected effectively using the instrumented-SAJs. The effect of water
absorption has marginal effect on the tensile strengths of the SAJs. On the other
hand, the tensile strengths and stiffness are dramatically decreased at elevated
temperature. MWCNTs have insignificant effect on the fatigue lives of the SAJs.

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