Quasi-Superplastic Uniaxial Tension Simulation using Viscoplastic Damage Model
Wu Yanqing,Zhang Keshi
(Department of Engineering Mechanics of Northwestern Polytechnical University, Xian , Shaanxi, P.R.China)

Abstract: The large deformation implicit algorithm on Chaboche viscoplastic constitutive equations is developed. Simulations of quasi-superplastic uniaxial tensile are implemented using damage model and non-damage model. From analysis of force/displacement curves, the process of quasi-superplastic deformation is divided into three stages: uniform deformation, necking development and rupturing. DM results show good agreements with experimental results for the two former stage, while NDM could only describe the first stage well. During rupturing process, force results calculated by DM are higher and lower by NDM than experimental ones due to higher strain rate sensitivity. DM can describe the phenomenon of multineckings, which is in good agreements with experimental results. Evolution of local strain rate distributions is indicative of necking extent. The longer distance between two serious neckings shows good ability to resist necking formation.
Keywords: Large deformation, Viscoplasticity, Quasi-superplasticity, Multiple neckings, Damage, Finite element simulation.