Using Flight Test Measurements on a Low-Fidelity Component to Predict Response on a High-Fidelity Component

Abstract

Measurements are often made during system field tests on a component of interest and the system. But the excitation forces are unknown. These tests are early in the development phase so the component may be of low fidelity. The environmental response of the high-fidelity component is what is desired to develop appropriate component qualification specifications. In this paper, the pseudo-force method from the field of transfer path analysis (TPA) is utilized in an analytical rocket and component example. A tractable number of frequency response function (FRF) measurements are made on the rocket and low-fidelity component. The low-fidelity component on a fixture is characterized by laboratory FRFs. Then the rocket and component are subjected to a random vibration loading in a flight test, with accelerations measured on the component and its base. Presumably at a later time, when the high-fidelity component is available, it is characterized with FRFs at the field measurement locations. The pseudo-force method is utilized to predict the flight response of the high-fidelity component without an additional flight test. A simple transmission simulator (fixture) is utilized in this work to minimize experimental errors at connection degrees of freedom (DOF).