Research On Optimal Layout Of Multi-Type Sensors For Structural Dynamic Response Reconstruction

In the structural health monitoring,the effectiveness of monitoring results and monitoring data is directly related to the sensor layout scheme.In the actual engineering structure,the number of sensors installed on the structure is often limited,so it is of great significance to study how to place the limited number of sensors in the optimal position of the structure to achieve the optimal monitoring effect.Most of the existing sensor optimization methods aim at structural modal parameter identification or damage identification,especially the optimal layout of single type sensor system.However,the actual engineering monitoring system contains a variety of sensors to obtain the overall and local information of the structure.The response reconstruction technology can obtain the structural response which is difficult to measure directly,and it can be used in the safety assessment of large complex structures.Therefore,this paper systematically studies the problem of “Research on optimal layout of multi-type sensors for structural dynamic response reconstruction”,mainly focusing on three aspects: structural dynamic response reconstruction method based on data fusion,sensor optimal placement based on step-by-step elimination method and sensor secondary optimal placement based on redundant data elimination.In view of the limitation of single sensor monitoring,this paper uses acceleration,displacement and strain sensors to identify the state vector of the structure,and uses the identified state vector to reconstruct the dynamic response of the structure based on the modal superposition method.The method is verified by simply supported beam.The results show that the multi-type sensor monitoring system,each type of data complement each other,and the reconstruction value of structural dynamic response is in good agreement with the real value.The validity of the reconstruction method of structural dynamic response based on data fusion is verified.The quality of structural dynamic response reconstruction is not only related to the method of response reconstruction,but also depends on the location of the sensors.In this paper,the minimum variance of average reconstruction error is taken as the objective function of sensor location optimization,and a sensor placement method based on the step-by-step elimination method is proposed.The finite element model of the bridge model is used to verify the method.The results show that the sensor placement scheme based on the step-by-step elimination method has better response reconstruction effect.In the process of sensor location selection,some measuring points are relatively close in space,and there are redundant data among the collected data.In this paper,the distance coefficient reflecting the degree of information independence is established.then the Fisher information matrix of the candidate degrees of freedom is weighted by the distance coefficient.Aiming at the maximum value of the determinant of the modified comprehensive Fisher information matrix,a secondary optimal sensor placement method based on redundant data elimination is proposed.The results show that the number of sensors is greatly reduced,the relative error of reconstruction is only slightly increased,and the degree of data redundancy between sensors is greatly improved.On this basis,the structural model is designed,and the effectiveness of the secondary optimal layout scheme is further verified by experiments.