A forward selection reverse path method for spatial location identification of nonlinearities in MDOF systems

摘要

Many kinds of nonlinear engineering structures have nonlinear components which are spatially localized. For these structures, it is usually needed to determine locations and types of nonlinearities firstly to make the subsequent procedure of parameter estimation more efficient and accurate. This paper presents a new approach to identify all the locations of possible nonlinearities in a multiple-degree-of-freedom structure. The method is a spectral approach since it is based on the reverse path method. Moreover, as a forward selection approach, it is able to identify nonlinearities of different types and locations one by one. This forward selection characteristic makes the method able to suffer less computational burden than using an iterate brute-force method when there exist multiple nonlinearities in the structure and the number of possible nonlinearities to be verified is large. Also, the method only needs one single excitation point which could be located at any node in the structure and no prior information about the underlying linear system is needed. One possible drawback is that in order to calculate the internal nonlinear forces, the response measurements at all the possible nonlinear nodes are needed. Another limitation is that the nonlinearities should be strong enough to be indicated in the response measurements which are polluted by noise.