Reduction of Overtesting during Vibration Tests of Space Hardware

Abstract

In conventional vibration testing of space hardware, the acceleration input to the base of a test article is controlled to specifications that are typically derived from the article interface acceleration at higher level of assembly. This conventional approach to testing has been known for over 30 years to greatly overtest the test article at its own natural frequencies. In recent years, NASA's Jet Propulsion Laboratory led the development and implementation of an improved method called force limited vibration (FLV) testing. In addition to controlling the input acceleration, the FLV testing measures and limits the reaction forces between the test article and the shaker. This paper discusses the overtesting problem associated with traditional vibration testing. Some of the key features of the FLV testing are outlined. Some of the results of a collaborative effort between the Canadian Space Agency and EMS in investigating and demonstrating the FLV testing by applying it to simple test articles are presented.