An in-situ identification method for joint parameters in mechanical structures

This paper presents an improved scheme based on the frequency response func tions (FRFs) for in-situ identification of joint parameters of mechanical s tructures. 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 presen t paper suggests an indirect estimation technique for unmeasured FRFs which are required for identification bur not available. Theoretical investigati on is made to delineate the effects of measurement noise and modeling error on indirect estimation and identification. Two index functions are introdu ced, which can indicate the quality of estimation or identification along t he frequency. The index functions are proven to be useful not only as a wei ghting function in the identification procedure but also for evaluating the frequency region appropriate for identification. A series of simulations a s well as experiments are performed for validation of the method.