Dynamic Shear Band Development in Plane Strain Compression of a Bimetallic Body

摘要

We study plane strain thermomechanical deformations of a prismatic viscoplasticbody of square cross-section and deformed at a nominal strain-rate of 5000/sec. The body has two thin layers placed symmetrically about the horizontal centroidal axis. The layer material differs from that of the body in only the value or the yield stress in a quasistatic simple compression test. The yield stress for the layer material is taken to be either one-fifth or five times that of the matrix material. Three cases, namely, when there is an elliptical void with its major axis aligned along the horizontal centroidal axis or the vertical centroidal axis, but the void center coincides with the center of the cross-section, and when there are two elliptical voids with major axes aligned along the vertical centroidal axis and a void tip abuts the layer/matrix interface are studied. The deformations are assumed to be symmetrical about the vertical and horizontal centroidal axes. It is found that in each case shear bands initiate from points on the traction free edges where the matrix /layer interfaces intersect them and propagate into the softer material. For the soft layer these bands initially merge into one and propagate horizontally.