Digital strain and temperature imaging technique

A technique for full-field measurement of surface temperature and in-plane strain using a single-grid imaging technique was demonstrated on a sample s ubjected to thermally induced strain. The technique is based on digital ima ging of a sample marked by an alternating line array of La2O2S:Eu+3 thermog raphic phosphor and chromium illuminated by a uv lamp. Digital images of th is array in unstrained and strained states were processed using a modified spin filter. Normal strain distribution was determined by combining unstrai ned and strained grid images using a single-grid digital moire technique. T emperature distribution was determined by digitally dividing images of phos phor intensity at two wavelengths. Combined strain and temperature measurem ents demonstrated on the thermally heated sample were Delta epsilon = +/-25 0 mu epsilon and Delta T = +/-5 K, respectively, with a spatial resolution of 0.8 mm.