MODELING BEARING FAILURE INITIATION IN PIN-CONTACT OF COMPOSITE LAMINATES

Failure induced by pin-contact in composite laminates was investigated . The experimental part of this research involved the use of a contact test in which a steel pin was pressed against the straight edge of a composite laminate. It was found that failure initiated at the edge ne ar the flat surfaces, and the failure mode in the 0 degrees-plies rese mbled the kink band observed in compression failure in unidirectional composites. Fiber microbuckling appeared to be the primary failure mec hanism. An approximate 3-D finite element stress analysis was performe d. The results show that linear elasticity is not adequate for predict ing contact failure of the laminate and that nonlinear behavior of the composite must be accounted for. A fiber microbuckling failure criter ion including effects of nonlinear matrix stress/strain behavior was d eveloped. Using the elastic-plastic analysis result in conjunction wit h the microbuckling criterion, the failure initiation due to pin-conta ct was successfully predicted. (C) 1998 Elsevier Science Ltd. All righ ts reserved.