Design of Shock Table Tests to Mimic Real-Life Drop Conditions

A systematic study, both experimentally and analytically, is conducted to evaluate the feasibility of using appropriate shock table tests to mimic the drop impact environment for components and systems adopted in portable electronics. Firstly, experiments are carried out to observe the dynamic characteristics of typical portable electronic systems and components under drop impact. Then a series of shock table tests with different constraint conditions are designed to mimic the real-life impact state. By comparing the typical results from shock table tests and those from drop tests, the correlation of shock table test parameters and drop tests conditions is investigated. The results reveal that the conventional fully constrained shock table test cannot mimic the real-life drop impact conditions, while an appropriate shock table test method should allow the sample to rotate freely. Theoretical analysis is developed to explain the mechanics of the impact scenarios. It is found that due to Hertz contact spring effect and the rotational acceleration during the impact, the acceleration of the centroid sample is significantly different to that of the table. In addition, acceleration estimated by traditional force-divided-by-mass method may underestimate the real acceleration of components inside the products.