The Effect of Interface Delays in Substructuring Experiments

Abstract

Normally, for feasibility reasons, tests must be conducted on scaled structures, although scaling can introduce other issues. An alternative solution is to experimentally test the part of the structure that is of particular interest, at full or closer to full scale, while numerically modeling the remainder of the structure. This method is termed real-time dynamic substructuring or hybrid testing. To complete the substructure interaction the forces required to impose the displacements on the physical model are measured and applied to the model in real-time. One of the key challenges is to compensate for the dynamics associated with the actuators that are imposing the displacements on the physical test-piece. Ideally these actuators would act instantaneously however even with sophisticated control techniques interface errors are inevitable. We used an example system to study the effects of interface error modeled as a delay, on the accuracy of the overall substructuring technique.