| Reliability and predicted life of solder joints are major concerns in the design of electronic packages. By analyzing the accumulating plastic stress or creep through finite element methods, the user can estimate the number of cycles to crack initiation and propagation, ultimately leading to failure. In the analysis, quick changes in configuration and other parameters may be desired, in order to observe the subsequent results. Through the development of macros and graphical user interfaces, this research aims to facilitate the analysis and user in teraction with the finite element model. Overall, the macros will allow a user to easily change parameters, modify loads, and receive results by a simple execution of the macro.;The finite element program of choice here is ANSYS. First, a 3D model of the package is developed to simulate the thermal cycle. This model, referred to as the global model, first runs through the temperature cycle, and has its results evaluated. From the global model, the critical joint is then identified. A submodel can be generated for a more accurate analysis of plastic work density and life cycle, if desired.;The submodel requires adequately fine element sizes, for accurate calculation of nonlinear properties, such as plastic work density and creep. The global model transfers its linear properties, such as elastic stress and strain, to the submodel. Therefore, the global model does not require fine details, if a submodel is to be developed afterwards. |
