An In-situ Identification Method for Joint Parameters in Mechanical Structures

Abstract

This paper presents an improved scheme based on the frequency response functions (FRFs) for in-situ identification of joint parameters of mechanical structures. Despite that measurement of FRFs at joint locations is essential for identifying the joint parameters of a structural dynamic system, it is often impossible to measure FRFs at joint locations. To this end, the present paper suggests an indirect estimation technique for unmeasured FRFs which are required for identification but not available. Theoretical investigation is made to delineate the effects of measurement noise and modeling error on indirect estimation and identification. Two index functions are introduced, which can indicate the quality of estimation or identification along the frequency. The index functions are proven to be useful not only as a weighting function in the identification procedure but also for evaluating the frequency region appropriate for identification. A series of simulations as well as experiments are performed for validation of the method.