Three-Dimensional Elastic-Plastic Constraint Analysis for Side Crack Tension Specimen

Abstract

A in-plane stress constraint factor Ciand a out-of-plane stress constraint factor Coare introduced to study the three-dimensional stress state and the elastic-plastic constraint effect of the crack tip. The deep crack specimens(a/W=0.5) and the shallow crack specimens(a/W=0.1) with different thicknesses are performed in the present study. By using the finite element analysis, the result shows that the thickness effect of the deep crack specimens is more obvious than that of the shallow crack specimens. For the deep crack specimens, the crack constraint enhances with the specimen thickness increase. When the specimen thickness is equal to the specimen width, the constraint levels in the middle 2/3 thickness of the specimen approach to those from the plane strain analyse. For the shallow crack specimens, the crack constraint is almost fixedness when the specimen thickness changes from three times of a crack length to a specimen ligament length. Namely, increased thickness is helpless to enhance the crack constraint effect. Therefore, a shallow crack specimen may be designed by the lesser thickness than the standard deep crack specimen.