Influence of component position on lead-free solder interconnections during drop test

When subjected to drop test, interconnections between components and test board experience high stresses mainly due to differential bending. Using analytical and numerical modal analysis, bending moments have here been calculated and shown to strongly depend on the location on the test board; the highest value not being found at the centre, as usually stated. In parallel, experiments to determine viscoplastic material properties at high strain rates (~1s^-1) for lead-free solder (SnAgCu) have been performed and used in drop test simulations. Inelastic strains calculated at different locations confirm results from the modal analyses and give a first insight into the development of a drop test failure criterion