Dynamic characterization of structural joints using FRF decoupling

Abstract

Dynamic characteristics of structural systems, in many cases, highly depend on joint properties. In order to predict the dynamic characteristics of assembled structures accurately, joint models are required. Due to the complexity of joints, it is extremely difficult to describe dynamic behavior of joints with analytical models. Reliable models are generally obtained using experimental measurements. In this study, substructure decoupling based on measured and calculated FRFs is used to model a structural joint. In the method proposed the FRFs of two substructures connected with a joint are measured, while the FRFs of the substructures are obtained analytically or experimentally. The joint properties are then calculated in terms of stiffness and damping values by using FRF based substructure decoupling. The method is verified with case studies using simulated experimental data. The limitations of the method in its application to engineering systems are discussed. © The Society for Experimental Mechanics, Inc. 2012.