Energy related model correlation criteria for modal analysis of fluid-structure interaction systems

Vibroacoustical problems are sometimes treated by modal analyis, which has been applied to air-filled shells. It is suggested to use the method for various types of liquid-structure interaction systems. Potential applications are water or oil hydraulic pipelines and heavy machinery actuated by fluid power. Modal testing of such systems should be accompanied by sensor placement strategies, test data assessment, and comparisons between theoretical and experimental mode shapes. In structural dynamics, these issues are covered by model correlation criteria like the classical modal assurance criterion (MAC). From the orthogonality relations of undamped vibroacoustical systems, two new criteria are developed. Their respective formulations are related to potential energy (POTMAC) and kinetic energy (KINMAC). Both criteria assume real values between zero and one. In practical applications of model correlation, it should be understood which values are acceptable. An approximation indicates that the limits for individual matrix elements can be adopted from the MAC. Numerical examples of POTMAC and KINMAC matrices are given for two different hydraulic press models. Analogies between POTMAC, KINMAC, and the rotor modal assurance criterion (RMAC) are pointed out. The new criteria can help to develop modal testing into a useful tool for systems with a vibroacoustical model structure. (c) 2020 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).