Research On The Method Of Dynamic Load Identification Based On The Newmark Method

The dynamic load information in the engineering structure always can't be directly measured.Therefore,the indirect method of inverting its real dynamic load by measuring the vibration response of the structure has attracted much attention.This paper studies the Load identification method of the multi-degree-of-freedom system and the continuous system based on the Newmark method.The Newmark method is a numerical method for solving structural dynamic response.Due to its good stability and adaptability,the inverse Newmark method is developed to solve the dynamic load identification problem.In this paper,the dynamic load identification method of multi-degree-offreedom system based on Newmark method is deduced in detail.Then the method is extended to modal space by modal coordinate transformation.The Newmark dynamic load identification method in modal space is proposed and the algorithm is given.The basic steps and recursive process,and the basic principles of modal truncation in modal space are studied.The numerical simulation is used to comprehensively analyze the dynamic load identification method for single-point and multi-point centralized dynamic load recognition.Then basd on the modal analysis theory of continuous system,the dynamic load identification method of continuous system is proposed.The theoretical algorithm of the method is deduced in detail by using simply supported beam.The numerical simulation and experiments are carried out to verify the method in continuous system load identification.Feasibility and reliability.The cumulative error caused by noise causes the drift of the dynamic load identification result,and the error divergence problem is overcome by the high-pass filter.Finally,the influence of the modal truncation order on the continuous dynamic load recognition result is analyzed,and the appropriate modal truncation order can be improved.Calculation efficiency and recognition accuracy.Through the simulation example and the beam test,the applicability and effectiveness of the proposed method for multi-point centralized dynamic load identification in multi-degree-of-freedom systems and continuous systems are verified.It shows that the method has high recognition accuracy and certain anti-noise ability,The basic law of dynamic load identification method based on Newmark method is summarized,which provides a new idea for dynamic load identification on time domain.