50 T. J. Skousen and R. L. Mayes Fig. 3.14 Physical responses for the four units to the individualized 6 DOF inputs at RC Accel 3X The individually tailored response control produces responses that are more representative of the responses from the field environments. Some buffer amplitude could be added to the desired responses when determining the individualized inputs to ensure that conservative testing is conducted. The authors caution the readers about applying conservatism to the inputs because each fixed base mode modes of the test article will amplify the added conservatism differently and may again jeopardize the test article with unnecessary failure. In future work, the individual tailoring process used to analytically shift modes could be replicated with FEM to investigate the resultant unit-to-unit variability in stress and strain states. Acknowledgments The authors are grateful for the work that Garrett Lopp performed with the modal testing of the RC on the plate fixture. We are also grateful for the work done at AWE providing data for the RC from system-level testing. A.1 Appendix A A.1.1 Review of Modal Theory for Base-Mounted Component on Fixture Mayes presented the original theory based on the transmission simulator approach, which he called the Craig-Bampton (CB) modal model [4, 5]. We repeat that here for the case of a rigid fixture. Consider a free component modal test with a rigid fixture attached. The test captures modal parameters for the free modes of the component and fixture. It is desired to transform the experimental model to a modal Craig-Bampton (CB) reduced model form which contains fixed base and free modes of the component and fixture. Consider component A attached to a fixture in Fig. 3.15. This test setup is instrumented so that there are enough accelerometers to capture the rigid body motion of the fixture and all elastic modes of interest for the component.
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