A COMBINED VARIATIONAL-PHASE FIELD METHOD FOR FULLY COUPLED THERMOMECHANICAL INTERFACE CONTACT AND DEBONDING PROBLEMS
Open Access
- Author:
- Wan, Wan
- Graduate Program:
- Civil Engineering
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- October 02, 2023
- Committee Members:
- Jay Regan, Professor in Charge/Director of Graduate Studies
Pinlei Chen, Chair, Minor Member & Dissertation Advisor
Amrita Basak, Outside Unit & Field Member
Gordon Warn, Major Field Member
Kostas Papakonstantinou, Major Field Member - Keywords:
- Phase Field
Crack Propagation
Fracture/Failure
Variational Multiscale method
Frictional contact
Debonding
Coupled Thermomechanical problem
Finite Element method - Abstract:
- Accurate prediction of failure in solids is of great importance, particularly within the context of thermomechanical problems. However, this task remains challenging in many engineering applications, especially for heterogeneous materials. While various computational methods have been developed for modeling the fracture caused by the mechanical loadings, there have been relatively few contributions focused on developing failure models with interface debonding or frictional sliding in a coupled thermal and mechanical setting. For heterogeneous materials such as polycrystalline silicon, at the macroscopic scale, fractures typically initiate from microscopic defects such as voids and cracks. The growth and propagation of these cracks ultimately lead to a deterioration in the load-carrying capacity of structural components. On the other hand, at the microscopic level, cracks can propagate along grain boundaries or through the grains themselves, which by itself, is a major concern for the overall performance. In order to capture both types of crack propagation, direct numerical simulation that incorporates all relevant fine-scale details throughout the fracture region is often infeasible due to prohibitive computational costs. Therefore, in this work, we propose a novel combined Variational Multiscale Discontinuous Galerkin and Phase Field (VMDG-PF) method for fully coupled thermomechanical interface contact and debonding problems. In this proposed framework, the phase-field approach is used to model arbitrary crack propagation, while the Variational Multiscale Method (VMS) is used to model interface debonding, damage, and frictional sliding. There are several unique features of the proposed VMDG-PF framework: (1) in the VMS method, the mechanical/thermal jump along the interfaces is modeled with the involving parameters naturally derived via the VMS method, (2) thermal conductivity is calculated utilizing different conductance conditions, (3) in the phase field method, we model the crack passing through the interior of the elements without an explicit representation of the complex geometry or enrichment of basis functions, and (4) the computational cost is reduced while maintaining the robustness and accuracy.