Predicted Vibration and Shock Environments for the Reusable Space Shuttle Orbiter

Abstract

Structural vibration response to aeroacoustic noise, engine-induced mechanically transmitted vibration, and mechanical shock were predicted for various orbiter locations of the proposed shuttle vehicle. Aeroacoustic-induced random vibration was calculated using (a) predicted acoustic and aerodynamic noise environments defined in a companion paper; (b) the Condos-Butler scaling method; and (c) reference aeroacoustic and vibration data from Apollo and Saturn V flight and vibroacoustic tests. Random vibration envelopes of 17 g–18 g rms were derived for five zones of the orbiter fuselage, and 22 g rms and 81 g rms for the vertical stabilizer and wings, respectively. Mechanically transmitted random vibration of 22 g rms was estimated for the aft fuselage from the staged-combustion orbiter engines during orbiter burn, using Saturn S-II flight data as reference and the Barrett scaling relationship. Mechanical shock during booster—orbiter separation was calculated to be an initial peak sawtooth with a maximum of 1.8 g peak and a duration of 400 msec. Landing shock was not expected to exceed 1.5 g peak or 350 msec, using a maximum sink speed of 10 ft/sec.