Paper number 1316

DYNAMIC INTERLAMINAR FRACTURE TOUGHNESS IN POLYMERIC COMPOSITES

C. T. Sun and J.L. Tsai

School of Aeronautics and Astronautics
Purdue University
West Lafayette, IN 47907

Summary

A modified ENF specimens with off mid-plane delamination precrack was used to determine the mixed mode dynamic interlaminar fracture toughness of fiber composites at high crack propagation speeds. A strip of FM-73 adhesive film was placed ahead of the tip of the delamination crack created during laminate lay-up to increase the crack initiation toughness so that after initiation an unstable crack propagation could be produced and high crack propagation speeds achieved. A finite element model was used for the numerical simulation of dynamic crack propagation. Dynamic delamination experiments were performed on modified ENF specimens of unidirectional AS4/3501-6 graphite/epoxy composite under three point bending. The results showed that the dynamic fracture toughness is not affected significantly by crack speed up to 1100 m/s.

Keywords

dynamic crack propagation, interlaminar fracture toughness, unidirectional composites.