抄録
In tensile test of steel specimens, there are several stages in stress-strain relation and strain distribution on the specimen surface is not uniform during the test. In this study, the author investigated measurement of strain distribution in steel specimens during tensile test using digital image correlation method. Plate specimens were used and images of specimen surface were taken continuously as a movie with a digital camera. Static images were taken from the movie file and displacement distribution was measured from the initial surface image before loading. It was possible to measure strain distribution on specimen surface from elastic deformation stage to the final local deformation stage for the whole tensile test. Change in plastic strain distribution during yielding stage was observed. And from the measured results, stress-strain relation was derived from uniform plastic deformation stage after yielding to the final local deformation stage just before fracture.
