An Experimental Analysis of Elastic-Plastic Stress by Means of Photoelasto-Plastic Method and X-Ray Method

Abstract

Elastic-plastic plane stresses in the notched specimens made of duralumin and carbon steel were measured by means of both the photoelastic coating method and the X-ray method. When plastic stresses were analyzed by means of the photoelastic coating method, the following assumptions were employed; the materials are isotropic and obeyed Mises yield condition and Prandtl-Reuss stress-strain rule.
From these experiments, we have obtained the following results. The stresses measured by means of the photoelasto-plastic method were in good agreement with those by the X-ray method in the case of the elastic plane stress state, but in the case of the plastic stress state, the stresses by the X-ray method were smaller than those by the photoelastic coating method. The propagating velocity of plastic region across the center section was smaller in the specimen with smaller notches than in that with larger notches, and moreover the velocity in carbon steel specimen was greater than that in duralumin. Furthermore, the rate of decrease in the plastic stress concentration factor at the bottom of notches of carbon steel was greater than that of duralumin.