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 lamin ates, prepared by autoclave and oven curing methods, was examined unde r static and dynamic loading. Static bearing strength was determined a s a function of bolt constraint and specimen geometry with particular attention to failure modes. The performance was very sensitive to late ral bolt tightening: a bolt with only a 'finger-tight' nut produced si milar to 100% improvement in bearing strength, compared with the perfo rmance of a pin-loaded hole. Some specimens were hygrothermally condit ioned and indicated a 10% deterioration in the bearing strength of the bolt-loaded hole. However, this was well below the magnitude of varia tion in strength which resulted under different methods of production. The fatigue endurance limit (N similar to 10(6)) at 1 Hz was only ach ievable at stress levels equivalent to 25% of the maximum static beari ng strength.