Local strain rate at crack tip: implications in stress corrosion cracking

Abstract

Local strain rate at a crack tip of a cracked cylindrical specimen was calculated as a function of the global strain rate externally applied to the specimen ends. The results demonstrate that local strain rate increased with time (as the load increased and the plastic zone spread), even when the global strain rate remained constant, as in the case of an externally applied constant displacement rate. In axisymmetric specimens, the crack tip strain rate increased quasilinearly as straining proceeded, whereas in the plane strain specimens the relationship between local and global strain rate was almost constant when a certain strain level was reached. The application of these results to stress corrosion testing is discussed.