Analytical and Numerical Analysis of Drop Impact Behavior for a Portable Electronic Device

Dynamic performance during drop impact is a great concern to semiconductor and electronic product manufacturers, especially for portable devices such as mobile phones. In this paper, the drop impact response of a mobile phone is investigated by an analytical dynamics model. In order to capture some most important affected factors, we decouple this problem to be a two-step analysis. First, finite element analysis is used to determine the effective stiffness for housing and PCB board, respectively. Second, a two-degree-of-freedom analytical dynamic model is developed to investigate the drop impact response. Such an approach allows parametric analysis to determine the important design parameters, which are important to the preliminary selection of geometries and materials of PCB boards and stiffness of housings so that the dynamic stability is maintained. Board level finite element analysis is also performed using input-acceleration model. The results are in good agreement with the analytical model results developed above. Finally, both methods are applied to evaluate the dynamic response of a commercially used cellular phone