Identifying goals for Ares 1-X modal testing

Abstract

A series of modal tests was planned for validation of the Ares 1-X Flight Test Vehicle (FTV) analytical model for control purposes. To support the controls analyses, knowledge of the first three pairs of vehicle bending modes is required. Planned modal testing consists of three tests: two subsystem tests and the FTV attached to its Mobile Launch Platform (MLP). Since the FTV as a whole would not be tested in its flight configuration, and the FTV / MLP testing would not be performed until late in the program schedule, it was necessary to identify appropriate goals for the subsystem tests that support the overarching goals for the FTV. This paper describes the analytical process employed to trace structural modes of the FTV to the tested subsystems. This traceability analysis - based on subsystem coupling and energy distribution - identifies subsystem modes important in describing the FTV modes of interest and evaluates the ability of different test configurations to provide data relevant to the system goals. ©2010 Society for Experimental Mechanics Inc.