Study On Time-domain Identification Of Dynamic Load Of Rotating Structures

The dynamic load time-domain identification is a process of reconstruction loads applied to structure through structural dynamic model and information of structural response. The problem of identification is the second kind of the inverse problem in the field of structural dynamic analysis. In engineering practice, measuring the dynamic loads directly is unable of extremely difficult. The methodology of load identification offers an indirect and convenient way to measure the loads. In recent years, the dynamic calibration of load identification has been widely developed and used, applied to simple structure successfully, such as simply supported beam. Dynamic loading identification has been an indispensable technology in engineering. However, to the best of our knowledge, few scientific literatures handle the method of load identification in the moving structure subjected to dynamic loads. In particular, the load identification in the continuous elastic rotating structure is nearly blank at home and abroad.This paper studies the time-domain identification technology of dynamic load based on orthogonal polynomials from the fixed structure to the flexible rotating structure to further improve the theoretical system of the dynamic load identification. From simplicity to complexity, this paper systematicly studies corresponding identification technology of dynamic load in-depth, for rotating Timoshenko beam, rotating thin plate, nonlinear rotating beam of rigid-flexible coupling.In the paper, the time-domain identification of concentrated dynamic load and distributed load are studied around the one-dimensional and two-dimensional continuous structures. Beginning with the forward problem of structural dynamics, finite element of the rotating structure is analyzed; and then the mapping relation between the response and dynamic load is calibrated; lastly the dynamic load is determined through the inverse mapping. The method of the time-domain identification is based on the theory of orthogonal polynomials in this paper. In fact, the identification of dynamic forces is changed into solution of fitting coefficients of orthogonal polynomial. The time-domain identification model of dynamic by this method greatly simplifies the inverse convolution calculation.In practical engineering, usually many points on structure can't be touched and measured, so this method can be used to solve this problem. Only sufficient number of measured points is needed to satisfy the identification precision and identify the coefficients of the orthogonal polynomials, and there is no special limit on the positions of measured points.Dynamic load identification theory for several rotating structure are established, and gives and publishes the demo example to prove the method. Numerical simulation shows that the method is simple, effective and feasible; as long as enough data of response points the identification force has high precision. Therefore it can be applied for engineering practice. The study of dynamic load identification on rotating structures in this paper makes lays the solid foundation for the further in-depth detailed research in the future.