题目：Surface Roughening and Localized Necking in Aluminium Alloys

报告人：Prof. P.D. Wu (吴沛东)
　　　　Department of Mechanical Engineering, McMaster University, Canada

时间：2018年5月15日（周二）10:00—12:00

地点：师昌绪楼403室

Abstract：

The finite element method is used to numerically simulate surface roughening and localized necking in AA6111-T4 under stretching. We assume that localized necking is associated with surface instability, the onset of unstable growth in surface roughening. The measured EBSD data (grain orientations and their spatial distributions) are directly incorporated into the finite element model and the constitutive response at an integration point is described by the single crystal plasticity theory. The effect on surface roughening/necking of sample geometry, strain rate sensitivity, work hardening, imposed deformation path, as well as the EBSD step size, spatial orientation distribution, and inhomogeneous deformation within individual grains are discussed. It is concluded that surface roughening is controlled by the spatial distribution of grain orientations through the thickness of the specimen, while localized necking depends strongly on both the initial texture and its spatial orientation distribution. It is also demonstrated that the initial surface topography has only a small influence on necking.