New Methods for Repeatable Impact Testing

Recent work has shown that due to the multiple impacts that result during an accidental drop of an electronic product, the propensity for damage to the product can be significantly higher than in a single impact. When viewed in light of these findings, conventional methods for drop-testing of products and equipment, either constrained or free, suffer from drawbacks. In the former, the object being tested is not allowed to move naturally during impact, and in the latter, it is difficult to control the orientation of the object at impact and to instrument it. In this paper we introduce a new method of drop-testing, that combines the advantages of the constrained and free methods, without their drawbacks. It is proposed that the object being tested be suspended onto a guided drop-table in the precise desired impact-orientation. The drop-table hits the ground first, but just before impact, the test object is released from suspension so it can move unrestrained thereafter. The main advantages of this method are that the object is free to move naturally during impact which provides for more realistic drop-testing. At the same time the product can be instrumented reliably, the tests are repeatable, and can be automated. A simple machine built to illustrate our novel drop-testing scheme is presented. Results of drop-tests performed using this machine are compared to similar free-drops and shown to be in good agreement. One of the goals of this project is to have our testing scheme accepted as part of industry standardized impact-testing methods.