Session: MF-16-02 Creep and Creep-Fatigue Interaction-2

Paper Number: 122668

122668 - High Temperature Tensile and Creep Strain Measurement Using Edge Image Analysis 

An image-based technique has been developed to measure the reduction of diameter of a round bar sample. This process is based on imaging a round bar sample, and ensuring sufficient contrast is provided to detect the edge of the sample. The physically measured initial diameter of the sample is then converted to a number of pixels, and as a tensile of creep test is performed, the reduction in diameter of the sample is determined via pixel count. For isotropic materials this reduction in diameter can be converted to axial plastic and or creep strains. For high temperature tests, images are acquired through a windowed furnace. This image-based technique enables the true stress – true strain rate to be captured and the stresses in the neck to be determined, which is not possible with conventional axial extensometers. The reduction of area and variability in notch radius in a notched bar tensile and creep test can also be captured, enabling the variability of stress triaxiality in a notched bar tensile and creep test to be determined. The accuracy of the method will be validated through comparison with post-test physical measurements and finite element model results. The benefits of this strain measurement technique compared to conventional extensometry will be discussed.

Presenting Author: Catrin Mair Davies Imperial College

Presenting Author Biography: tbc

Authors:

Catrin Mair Davies Imperial College
Chloe Parker Imperial College London
Jorge De Andres Imperial College London
Chen Liu Imperial College London