Volume 24, Issue 3 (May 1996)
Determination of the Geometric Profile and Stress/Strain State in the Necked Region During Inelastic Deformation at Elevated Temperatures Using a Non-Contact Measurement Technique
An improved testing methodology for determining the geometric profile and true stress/true strain at elevated temperatures through continuous monitoring of the specimen profile in the necked region using a video camera is demonstrated through a slow creep tensile test. The results show that the video camera is an appropriate tool for accurately monitoring specimen necking at elevated temperatures, and that the true stress and strain can be adequately determined from the specimen profile. Based on this test methodology, true strain rate-controlled creep testing can be carried out. This is essential for determining the true material parameters required for establishing appropriate constitutive equations for realistic finite element modeling.