TWI Industrial Member Report Summary 502/1994
S Manteghi and D J Abson
Fibre reinforced metal laminates (FRMLs) are modern composite materials developed primarily for aerospace applications. The earliest members of the group, and the ones most extensively studied to date, are based on aluminium alloys and aramid fibres. These materials are collectively referred to as ARALL (Aramid Reinforced Aluminium Laminate). Previous studies have shown that plain ARALL has very high fatigue strength, indicating that the strength of any structure made of ARALL and subjected to fluctuating loading would almost certainly be governed by the fatigue strength of the joint, where experimental data are still fairly limited.
The present project was aimed at studying the fatigue performance of adhesively bonded ARALL-3, a widely available FRML developed specifically for fatigue sensitive applications. Single-lap shear specimens in two different thicknesses and covering three different overlap lengths were tested in air under constant amplitude sinusoidal loading. The mode of failure, including the most likely site for fatigue crack initiation, was also investigated.