An Danh Nguyen

On Recent Progress in Shakedown Analysis and Applications to Large-Scale Problems

Shakedown and Limit Analysis have proven to be powerful tools to determine limit states of mechanical structures operating beyond the elastic limit under monotonous or variable thermo-mechanical loads. In this paper, recent results obtained by using the lower-bound theorem of shakedown analysis are presented focusing on new methods for solving large-scale problems by using a selective algorithm. Illustrative examples from mechanical and pavement engineering are presented.

A Gradient-Enhanced Damage Model for Viscoplastic Thin-shell Structures

A finite element model of non-local damage viscoplasticity for dynamic analysis of thin-walled shell structures is presented. To take void nucleation and growth into account, a non-local implicit gradient formulation is employed. The free energy function includes both a non-local damage variable on the mid-surface of shell structures and a local one in shell space.Local constitutive laws considering viscoplastic behavior,isotropic hardening and isotropic ductile damage leading tosoftening are used. The performance of the proposed approach is demonstrated through the numerical simulation of shock-wave loaded structures