Research And Application Of Optimal Sensor Placement In Structural Modal Testing

With the rapid development of high-precision,high-speed,and high-efficiency of various large-scale structures,structural static characteristics analysis has been unable to meet the identification of structural system parameters,and modal tests are usually used to determine the vibration mode characteristics of the structure.In the actual model test,for the sake of test effect,time and economic costs,it is often desired to place the least number of sensors at the optimal measuring point position under the premise of obtaining a complete modal shape in order to collect the most accurate,comprehensive structural vibration modal data information,i.e,sensor configuration optimization.In recent years,intelligent optimization algorithms have been widely studied in the field of sensor configuration optimization.Aiming at the optimization of sensor configuration in structural dynamics analysis,the idea of estimating probability model in distributed estimation algorithm is introduced into the harmony search algorithm,and the improved new algorithm is applied to the modal parameter testing of steel truss bridge model to optimize the sensor.The research content and main conclusions are as follows:(1)A new improved distribution estimation and acoustic search algorithm is proposed for the problem that the harmony search algorithm generates new elements in a random way and the search model is blind.A complementary search mechanism is used,and the idea of model updating in the distribution estimation algorithm is introduced into the harmony search algorithm.Through the establishment of a probability model for sampling,each component of the solution is transformed from a random search to a search of the entire interval,thereby broadening the search range of the algorithm.Finally,six new standard test functions are used to test the new improved algorithm.The results show that the distributed sounding search algorithm has better performance than the original harmony search algorithm.(2)A new optimal sensor placement algorithm based on estimation distribution algorithm and harmony search algorithm is proposed for the sensor configuration optimization in the modal parameters test of steel truss bridge model.The mathematical model of sensor optimal configuration is established,and the improved algorithm is applied to optimal sensor placement.By analyzing the examples and comparing it with the original harmonic search algorithm,the effectiveness of the proposed method is verified.The optimal sensor layout scheme for a steel truss bridge model is obtained,and the optimal number of sensor arrangements and location of the measuring points are obtained.(3)Apply actual modal test for steel truss bridge model.Aiming at the selection of reference points and measuring points in the actual modal test of steel truss bridge models,the modal participation degree is used to select the excitation points in the actual modal tests.The results of sensor optimal layout based on distributed estimation and acoustic search algorithm are applied to the actual modal parameters test of steel truss girder bridge model.An experimental modal analysis system is established and its natural frequencies and mode shapes are obtained through a series of comparing with the finite element modal analysis results,The correctness and validity of the results were verified.The modal parameters of the steel truss bridge model are measured.