An Error Measure for the Shock Testing of Scale Models

Abstract

Abstract: In a variety of situations, an undesired shock excitation is applied to a master structure that supports shock-sensitive equipment. Often, one wishes to design and test a master structure that transmits the least amount of shock energy to the attached equipment. In scaled testing of new designs, a major task is to design and construct “equipment emulators ” – inexpensive mechanical systems which approximately mimic the dynamic behavior of the actual full-scale equipment as seen by the master structure. A new method is presented for assessing the fidelity of equipment emulators and for interpreting test data taken in the presence of imperfect emulators. The proposed approach uses easily obtainable frequency-domain impedance descriptions of the master structure and actual equipment at the attachment points. These ideas may provide a path by which experimentalists can efficiently arrive at conceptual designs of emulators that promise a specified degree of fidelity in terms of attachment point velocities and their associated shock spectra. The ideas are illustrated by application to the emulation of commercial-grade electronic cabinets for the testing of novel ship deck structures.