THE FAILURE MORPHOLOGY OF PEEK CARBON-FIBER +/- 45-DEGREES ANGLE-PLY LAMINATES

The ultimate strength of certain thermoplastic matrix laminates is observed to be strongly dependent upon the stacking sequence. Such effects are thought to be due to the development and action of through-thickness stresses at the edges of laminates. However, the action of such stresses is not normally considered in Classical Laminate Theory. This paper describes experimental studies of the development of damage in, and subsequent failure of, a family of laminates that exhibit "through-thickness" effects. Important differences between the mode of failure and development of damage prior to failure are identified, and these observations correlated with other workers' predictions concerning the presence and actions of edge stresses.