An Impact Load Identification Method Based on Green’s Kernel Function

Abstract Ships and offshore platform structures experience complex dynamic loads during their lifetime. Impact loads is one of the types of dynamics loads where the duration of action is very short. The relative velocity between impacting body and the structure being impacted is usually high, and which may have a significant influence on the safety of ship structures. The load, as an input of structure calculation, plays an important role during the calculation progress and directly influences the accuracy of the result. Identification of the loads acting on the structures are important for structure design, analysis of strength, estimation of fatigue life and also data driven models of structures, however, most of these types of loads are difficult to identify. A possible approach is to measure the response of the ship structure, and then identify the location of action and the time histories with load identification techniques. In this study, a Green’s kernel function based time-domain inverse method for estimating the impact load is studied. The Tikhonov regularization method and TSVD method are used to deal with the ill-conditioned problem in the inversion, and the ill-conditionness of the matrix is reduced to a certain extent so as to improve the identification accuracy. An Improved Maxwell-Betti method is used to identify the location of impact load at an unknown position. The proposed method is validated through numerical simulation and experiment for a typical structure used in naval architecture and ocean engineering.