Accurate thermal-induced structural failure analysis under incompressible conditions

Abstract

In this work, the performance of the mixed 3-field displacement/deviatoric-strain/pressure (u/e/p) finite element is examined for nonlinear thermo-mechanical structural applications under incompressible behavior. The proposed FE model increases the solution accuracy in terms of strains and stresses, guaranteeing mesh-objective results in nonlinear analyses. Structural failure is modelled with J2-plasticity and J2-damage constitutive laws, introducing the isochoric behavior, typical of metals, in the material response. The solution of the coupled thermal and mechanical problems follows a staggered scheme and temperature dependent material properties are introduced to study the effect of the thermal coupling in the mechanical problem. This FE approach is applicable with any interpolation basis: triangles, quadrilaterals, tetrahedras, hexahedras and prisms. A set of numerical benchmark problems is proposed to examine the influence of the enhanced accuracy of the proposed model in thermally-induced structural failure analyses in incompressible conditions. The study includes the comparison of the u/e/p and u/pand FE formulations, where the effect of the thermal coupling in the problem is investigated. The superior performance of the 3-field formulation with regard to the evaluation of collapse mechanisms, failure loads, mechanical dissipation and numerical stability in incompressible situations is shown.

The authors gratefully acknowledge the financial support from the Spanish Ministry of Economy and Competitiveness, through the Severo Ochoa Programme for Centres of Excellence in R&D (CEX2018-000797-S). This work has been supported by the European Union’s horizon 2020 research and innovation programme (H2020-DT-2019-1 No. 872570) under the KYKLOS 4.0 Project (An Advanced Circular and Agile Manufacturing Ecosystem based on rapid reconfigurable manufacturing process and individualized consumer preferences) and by the Ministry of Science, Innovation and Universities (MCIU), Spain via: the PriMuS project (Printing pattern based and MultiScale enhanced performance analysis of advanced Additive Manufacturing components, ref. num. PID2020-115575RB-I00).

Peer Reviewed

Postprint (author's final draft)