The Optimal Design Of Strain Sensor Based On BSHM Of Strain Modal Assurance Critrtion

Sensor system is an important component of the bridge structural health monitoringsystem. Theoretically, the more sensors are used, the more comprehensive structural responseinformation is obtained. But because of running state of structures and economic reasons, for abridge it is impossible to place sensors on every degree of freedom. The fundamental principleof placement optimization of sensors is using as few as sensors to obtain reliable andcomprehensive information of bridge health state.This paper summarized the optimal placement and the present research and the newestprogress of sensor comprehensively. By connecting the finite element model of Haihe Bridge,it developed the modal frequency and vibration mode. Besides, it discussed the rules of modalassurance criterion of sensor’s optimal placement detailed. And it applied the method on HaiheBridge. The main content is as following:(1) The use of Midas/Civil finite element model of the Haihe Bridge, the bridge of eachmain site and the boundary conditions make it as realistic as possible. The finite elementmodel of the load effects of stress analysis of the Haihe Bridge(2) Papers study optimal allocation problem for the strain sensor. Confidence criteriabased on the displacement mode deduced according to the relationship between thedisplacement and strain, the Strain Modal Assurance Criterion. Optimize the layout of strainmodal confidence (Strain of Modal Assurance Criterion, SMAC) matrix evaluation ofmeasured points(3) Confidence Level sensor based on the strain modal initial configuration, in largebridges, how to determine the2-norm of the evaluation interval to the initial configuration ofthe optimal sensor placement. For the continuous beam segments can span an evaluationinterval; Span a large steel box girder segment, from the crest to determine the evaluationinterval,a crest segment an evaluation interval. Evaluation intervals to determine the initialconfiguration has a direct impact on the optimal sensor placement.(4) Selection of the modal form for the configuration of the sensor influential,recommended the selection and direction of sensors to monitor the vibration associated withtype. Optimize the allocation of the strain sensor based on the strain modal assurance criteria, based on the finite element model of the Haihe Bridge analysis, to calculate the strain modalmatrix. Accumulation method on the sensor in accordance with the initial configuration of thesensor, to further optimize the configuration, can make the SAMC matrix of the largestnon-diagonal elements quickly reaches the preset value, and completed to optimize the layoutof the sensor.