Temperature variations around the crack tip during a fracture test

Abstract

Preliminary results are reported of the temperature variations in a fatigue pre-cracked compact tension specimen ofAISI 316, subjected to a uniformly increasing cross-head displacement. The temperature variations in the regions surrounding the crack tip are sensed by three point-like thermistors.

At the thermoelastic-plastic instability the load vs. time characteristic exhibits a barely perceptible kink. Conversely, the initial thermoelastic cooling is followed by a sudden temperature rise near the crack tip and a delayed, smoother rise at greater distances. This experimental procedure, based on " thermal emission " allows one to identify with precision the formation and development of the plastic zone