Abstract
The low compressive strength of Kevlar reinforced composites causes concern about the ability of these materials to withstand bearing loads in bolted joints. This paper presents the results of an experimental investigation of the pin bearing load-deflection response of (0/90/+-45), (0/90) and (+-45) Kevlar 49 fabric/epoxy laminates. Laminate thicknesses from 0.075 in. to 0.300 in. were examined for pin diameters ranging from 0.125 in. to 0.500 in. Results of this study revealed three significant points: (1) a synergistic effect takes place in the (0/90/+-45) ply stacking sequence which results in higher yield and ultimate strengths than the (0/90) and (+-45) laminates; (2) bearing strength varies inversely with pin diameter, probably due to the statistical strength behavior of these materials; and (3) nominal bearing yield strengths are very low (10 to 20 ksi). It is concluded that joint designs should incorporate local reinforcement in bolted or pinned areas.