Virtual element method for thermomechanical analysis of electronic packaging structures with multi-scale features

Abstract: This paper presents two approaches: the virtual element method (VEM) and the stabilization-free virtual element method (SFVEM) for analyzing thermomechanical behavior in electronic packaging structures with geometric multi-scale features. Since the virtual element method allows the use of arbitrary polygonal elements, the inherent mesh flexibility of VEM allows localized mesh modifications without affecting global mesh structure, making it particularly effective for the analysis of electronic packaging reliability involving complex geometries and multiple geometric scales. The approach implements a novel non-matching mesh generation strategy that strategically combines polygonal meshes for complex small-scale regions with regular quadrilateral meshes for larger domains. The VEM formulation addresses both heat conduction and thermomechanical coupling problems, with comprehensive verification through analytical benchmarks and practical electronic packaging case studies, including Through-Silicon Via (TSV), Ball Grid Array (BGA), and Plastic Ball Grid Array (PBGA) structures. Results demonstrate that the method accurately captures stress concentrations at material interfaces and provides reliable thermal and mechanical response predictions. Some MATLAB codes for the numerical examples are provided at https://github.com/yanpeng-gong/VEM-electronic-packaging and on the VEMhub website (www.vemhub.com).