BEARING STRENGTH OF AUTOCLAVE AND OVEN CURED KEVLAR EPOXY LAMINATES UNDER STATIC AND DYNAMIC LOADING

The pin bearing behaviour of woven Kevlar fibre-reinforced epoxy laminates, prepared by autoclave and oven curing methods, was examined under static and dynamic loading. Static bearing strength was determined as a function of bolt constraint and specimen geometry with particular attention to failure modes. The performance was very sensitive to lateral bolt tightening: a bolt with only a 'finger-tight' nut produced similar to 100% improvement in bearing strength, compared with the performance of a pin-loaded hole. Some specimens were hygrothermally conditioned and indicated a 10% deterioration in the bearing strength of the bolt-loaded hole. However, this was well below the magnitude of variation in strength which resulted under different methods of production. The fatigue endurance limit (N similar to 10(6)) at 1 Hz was only achievable at stress levels equivalent to 25% of the maximum static bearing strength.