Single point vs multi point acceleration transmissibility concepts in vibration testing

This paper discusses motion transmissibility concepts and their application to test environments. When a test item is attached to a vehicle at a single point and field external force effects are negligible, test item accelerations can be predicted by using the acceleration transmissibility FRFs and the test item's single point field interface acceleration represents the test item's input. When the test item has multiple interface points, the acceleration transmissibility FRF concept is extended by defining a transformation such that the multiple field interface accelerations can be used as test item's inputs in laboratory simulations. This transformation is defined by the Q-Transmissibility matrix that is obtained from the test item's response model, i.e., interface driving point and transfer FRFs. The Q-Transmissibility approach reduces to the standard single point transmissibility FRF approach for the case of a single interface point. Experimental results employing the Q-Transmissibility approach are shown in order to investigate its feasibility in predicting the test item's dynamic behavior.