On instability of constitutive models for isotropic elastic-perfectly plastic material behaviour at finite deformations

Abstract

The main goal of this work is to test the possibility of a newly introduced constitutive law to model the behaviour of the isotropic elastic-perfectly plastic material which is exposed to large elastoplastic deformations. The proposed constitutive relation is based on the hypo-elastic relation and the inelastic INTERATOM model. The verification of the model is done by its implementation into the commercial software ABAQUS/Standard via the user subroutine UMAT. For that purpose, the large simple shear problem is studied where selected objective corotational rates, i.e. the logarithmic rate, the Jaumann rate and the Green-Naghdi rate, are individually implemented in the aforementioned constitutive relations. The obtained results are compared mutually and with the relevant literature. The proposed constitutive model is also used to test the behaviour of the part of a real engineering structure, i.e. a seismic isolator, in order to obtain the correct input data for further analysis of superstructure behaviour due to seismic excitation.

Analysis of the seismic response of an RC frame structure with lead rubber bearings

“…It has been confirmed that the lead core provides an adequate level of energy dissipation [4,[10][11][12][13]. The numerical models for the analysis of the properties of a LRB were also developed [12,[14][15][16][17]. The seismic analysis of base isolated structures confirmed that the use of LRB has a favourable effect on the structural response [18][19][20].…”

“Nonlinear Dynamics of Mechanical Systems” dedicated to 75th birthday and 52 years scientific contribution of Prof. Katica R. (Stevanovic) Hedrih

“…Mirtaheri and Zohoor 13 introduced the concept of quasi-velocities to obtain alternative equations of motion through Lagrange formalism, that eliminating singularities and reduce violation of constraints during numerical integration. A constitutive relationship for modeling of elasticperfectly plastic behavior in large deformation has been developed by Trajković-Milenković et al 14 and the model using three well-known objective rules is validated with commercial software.…”