Digital Strain and Temperature Imaging Technique

Abstract

A technique for full-field measurement of surface temperature and in-plane strain using a single-grid imaging technique was demonstrated on a sample subjected to thermally induced strain. The technique is based on digital imaging of a sample marked by an alternating line array of La 2 O 2 S:Eu +3 thermographic phosphor and chromium illuminated by a uv lamp. Digital images of this array in unstrained and strained states were processed wing a modified spin filter. Normal strain distribution was determined by combining unstrained and strained grid images using a single-grid digital moire technique. Temperature distribution was determined by digitally dividing images of phosphor intensity at two wavelengths. Combined strain and temperature measurements demonstrated on the thermally heated sample were Δe =± 250 μe and ΔT=± 5 K, respectively, with a spatial resolution of 0.8 mm