Design of shock table tests to mimic real-life drop conditions for portable electronic device

Abstract

Mechanical shock tests are very important for portable electronic products such as notebook computers and mobile phones because these products are subjected to high risks of impact loading. Impact loading often plays a critical role in the functional performance and mechanical reliability of electronic components and devices. Drop tests are adopted usually to the overall product to assess the structural and functional integrity. Traditional test method is to drop the products from a certain height with a quick release hook or drop tester. The obvious advantage for these methods is that they can directly duplicate the field impact scenarios. However, the test repeatability can not be guarantied in drop tests, because it is difficult to control the orientation of the object at impact and to instrument it. Moreover; by considering the real impact conditions, drop tests are not applicable for the shock reliability tests of individual components. Shock table tests are carried out to overcome the drawbacks described above. A shock impulse with a given shape, magnitude and duration is applied to the shock table and then imparted to the sample product or component fasted to the table. However, the shock table test is a simulation of the real-life drop impact process. To make the shock table tests adequately mimic the real drop impact, it is critical to make correlation between the shock table test parameter and field conditions. The present paper aims to conduct a systematic study, both experimentally and analytically, to evaluate the feasibility of using appropriate shock table tests to mimic the shock environment for components and systems adopted in portable electronics. Firstly, dynamic characteristics of typical portable electronic systems and components under drop impact are studied, and then effective shock table test methods are developed for adequately mimic the real-life impact state. At last, 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 are investigated.