Non-uniqueness, stability and bifurcation analyses in elasto-viscoplastic boundary value problems with no inertia. (1st July 2022)

• Record Type: Journal Article
• Authors: Wang, Huan; Kotronis, Panagiotis; Sciarra, Giulio
• Is Part Of: International journal of engineering science. Volume 177(2022)
• Publication Date: 2022-07-01
• Subjects: Elasto-viscoplasticity -- Uniqueness -- Strain localization -- Regularization -- Second gradient -- Bifurcation -- Linear perturbation analysis -- Stability; Engineering -- Periodicals; Ingénierie -- Périodiques; Engineering; Periodicals; 620
• DOI: 10.1016/j.ijengsci.2022.103714
• Languages: English
• ISSNs: 0020-7225

Abstract

Abstract: The article focuses on non-uniqueness, bifurcation and stability conditions in elasto-viscoplastic boundary value problems when inertia terms are neglected. Analytical and numerical studies are presented to investigate the capability of an elasto-viscoplastic model to regularize the behavior in the occurrence of strain localization with respect to number of strain bands formed and mesh dependency. It is found that elasto-viscoplasticity in a Cauchy medium neither restores the uniqueness of the solution nor provides mesh independent results. A high value of the viscosity parameter can sometimes provide results that are mesh independent, up to a certain limit strain, as it actually modifies the response of the constitutive law by an ad-hoc increase of its hardening branch. On the contrary, coupling elasto-viscoplasticity with a second gradient model that introduces an internal length parameter reproduces realistically the rate dependent behavior and regularizes the results.