| A new algorithm for coupling boundary and finite element methods is developed for transient two dimensional heat conduction and thermoelastic analyses of regions with dissimilar materials and geometric discontinuities. Such regions are susceptible to failure initiation in electronic devices. As the component size decreases while enhancing performance, the accurate prediction of thermal and thermoelastic response of such devices is critical for achieving acceptable design. This study concerns both the conduction heat transfer and thermoelasticity. Solution to transient heat conduction equation provides the non-uniform thermal field for the thermoelastic analysis. Although the finite element method (FEM) is highly efficient and commonly used, its application with conventional elements to complex layered structures with length parameters varying in order of magnitudes leads to inaccurate and mesh dependent results. The accuracy of the results from the boundary element method (BEM) formulation, which requires computationally intensive integration schemes, is much higher than that of the FEM. This new algorithm combines the advantages of both methods while not requiring the commonly accepted iterations along the interfaces between BEM and FEM domains. The BEM part of the solution, acting as a global element, captures the singular nature of the solution variables arising from geometrical and material discontinuities and, eliminates the mesh dependency. |
