ISSN: 1945-7553
CODEN: JTEVAB
Page Count: 9

A Computerized Test System for Thermal-Mechanical Fatigue Crack Growth

Marchand, N
Research Assistant and Professor, Massachusetts Institute of Technology, Cambridge, MA

Pelloux, RM
Research Assistant and Professor, Massachusetts Institute of Technology, Cambridge, MA

(Received 11 July 1985; accepted 22 April 1986)

Abstract

A computerized testing system to measure fatigue crack growth under thermal-mechanical fatigue conditions is described. Built around a servohydraulic machine, the system is capable of a push-pull test under stress- or strain-controlled conditions in the temperature range of 25 to 1050°C. Temperature and mechanical strain are independently controlled by the closed-loop system to simulate complex inservice strain-temperature relationship.

A d-c electrical potential method is used to measure crack growth rates. The correction procedure of the potential signal to take into account powerline and RF-induced noises and thermal changes is described. It is shown that the potential drop technique can be used for physical mechanism studies and for modelling crack tip processes.

Keywords:
thermal-mechanical fatigue, crack growth, fatigue, potential drop

Paper ID: JTE10347J
DOI: 10.1520/JTE10347J
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