One-shot thermal and kinematic field measurements: Infra-Red Image Correlation

Abstract

Strain localization phenomena occur in many materials in different forms, such as PLC & Luders’ bands or Shape Memory Alloy stress-driven martensitic phase transformation. The development of kinematic and thermal full-field measurement techniques, like Digital Image Correlation (DIC) and Infra-Red (IR) thermography helps understanding these tricky phenomena and allows for the identi??cation of such material behaviors. When such kinematic and thermal measurements are coupled, they even offer a full thermo-mechanical characterisation. Unfortunately the space and time association of both ??elds remains a major di??culty (antagonist surface texture requirements, imaging devices having di??erent pixel number and acquisition rate...). To get round this problem, the present paper introduces a much simpler experimental approach: a novel extended DIC technique applied to a single set of IR images gives access to both displacement and temperature ??elds decomposed over the same discretization. A first application is performed, where the strain localization due to the phase transformation of a NiTi SMA and its associated thermal dissipation are jointly measured.