Prediction on Nominal Stress-Strain Curve of Anisotropic Polycrystal with Texture by FE Analysis

Abstract

In order to predict nominal stress-strain (S-S) curve in tensile test for a commercial purity titanium (hereafter, CP-Ti) with texture, three boundary conditions are elucidated as well as plastic anisotropy in three-dimensional finite element (FE) analysis. Three boundary conditions are a free case, a full constraint case at both ends of specimen, and a simulated case based on empirical data. In the simulated case, the shape change and the nominal S-S curve can be well predicted with deviation smaller than 10%. The origin of localized necking is concluded not due to the plastic instability but due to the constraint at both ends of specimen. Deviation point of the nominal S-S curve at the simulated case from that of the free case has been suggested as the onset of localized necking of CP-Ti, which is determined as 0.25 in transverse direction and 0.50 in rolling direction.