Vibration Test Procedures for Orbiter Sidewall-Mounted Payloads. Phase 2

Mechanical vibration tests of payloads mounted on the Space Shuttle Vehicle (SSV) cargo bay sidewall are currently performed in compliance with USAF Space Division Document SD-CF-0206, which specifies an acceleration level at the input to the payload. This procedure does not take into account the loading of the sidewall structure by the payload at the resonance frequencies of the payload where the payload apparent weight becomes large. The result is potentially severe overtesting of payloads at their resonance frequencies where payload damage is most likely. In this study, a new mechanical vibration test procedure has been developed that takes into account the mounting point impedance of the sidewall structure, and allows a well defined reduction or notching of the input acceleration levels at payload resonances based upon an input force limit to the payload. The validity and practicality of the procedure has been demonstrated by experiments on a simulated OASIS payload with an Adaptive Payload Carrier (APC). A complete vibration test specification detailing the procedure is presented. See also Phase 1, ADA220773.