Finite element formulation and adaptive solution approach for large-scale thermomechanical problems with complex contact conditions

摘要

Traditional thermal stress analysis is based on an uncoupled approach in which the thermal problem is solved on a fixed geometry, and the resulting temperatures are then used to load a mechanical problem. In contrast, a fully coupled thermomechanical analysis solves the thermal problem on the deforming geometry and incorporates thermal loads into the mechanical problem. Thermal contact, in which heat flow paths depend on the mechanical deformations of adjacent surfaces, is a major component of many fully coupled thermomechanical analyses. This paper describes the development of a Lagrangian finite element thermomechanical contact methodology. The paper focuses on the formulation and implementation of thermal contact in two dimensions. The proposed approach accommodates arbitrarily large relative motions of contact surfaces, fully unstructured meshes, pressure-dependent contact resistance, conduction across small gaps, and approximate models for convection and radiation. The proposed thermal contact formulation has been implemented in the Lawrence Livermore National Laboratory public code PALM2D and has been used to solve a diverse set of thermomechanical problems. Examples demonstrating the performance of this code on large deformation thermomechanical problems are presented and discussed.