EFFECTS OF RATE ON CRACK GROWTH IN A RUBBER-MODIFIED EPOXY

摘要

Dramatic rate effects on crack propagation were observed in the 10-phr rubber-modified epoxy. This may originate from the influence of rate effects on extrinsic and/or intrinsic toughening in this material. This study indicates that the extrinsic toughening is essentially independent of crack velocity. Hence, the strong rate effects may arise from the velocity dependence of the intrinsic toughness. Furthermore, the crack instability may result from a transition of deformation mechanism when the deformation rate ahead of the process zone is sufficiently high.