A Study on the Dynamic Interaction of Shock Response Fixtures and Test Payload

Abstract

Shaker system physical characteristics (e.g. shake tables, modal shakers, and shock fixtures) vary from one laboratory to another. Parameters such as size and payload capacity, make every system's dynamic characteristics unique. The commonly used control accelerometer cannot adequately adjust for the actual dynamic interaction/dynamic coupling effects between the test article and excitation fixture. Therefore, the payload/test article deformation will vary from test fixture to test fixture, making every test different—even with the same Shock Response Spectrum (SRS).

In order to properly address the dynamic coupling and dynamic interaction that results, and to subject the test article to a vibration level that provides the proper excitation, customization of the shock response input is necessary.

This work focuses on the identification as to how the article under test is affected by the attachment to the excitation fixture. Models are presented to show how the test article response is distorted by the dynamic interaction with the test fixture.