Research On Flexibility Method Of Structural Damage Diagnosis Based On Coordinated WSN

With the continuous development of science and technology,large-scale structures like mushrooming increasingly large,their life-cycle and security are also attracted human's attention,in order to protect human property and safety,structural damage diagnosis is more and more important.The traditional structural damage diagnosis technology uses wired sensor networks(WSN)and requires a large number of cables to connect to the control center.It is expensive and inconvenient to install.The wireless sensor has the characteristics of small volume,low cost and easy installation.It can effectively compensa te the wired sensor Shortcomings.The flexibility matrix is sensitive to the low order frequency of the structure,and the influence of the high order frequency is negligible.Under the environment excitation,only the first few modes of the structure can be obtained to construct the high precision flexibility matrix.In this paper,aimed at the planar truss structure,a damage locating vector method based on the strain compliance matrix is proposed,and the simulation results show that the method is effective.The main research work and achievements are as follows:The problem of energy consumption has been the difficulty of application of structural health monitoring in WSN.Network energy consumption and network traffic are closely related,in order to reduce the communications volume of the wireless sensor networks,this paper uses data fusion technology and coordinated information processing.Firstly,the sub-structure of wireless sensor networks is divided,and the displacement information of the struct ure is transmitted by cooperative information processing.The CPU computing power of wireless sensor is fully utilized.Then,using Natural Excitation Technique and Eigensystem Realization Algorithm for data fusion processing,so as to achieve the purpose of reducing the communications volume of the wireless sensor networks.Two kinds of damage index,generalized internal force and strain flexibility matrix difference,are proposed based on the characteristics of strain flexibility matrix.The quality normalized coefficient of the structure obtained by the method of mass perturbation is combined with the modal parameters of the structure to obtain the strain flexibility matrix of the structure.Due to the orthogonality of the structural modal parameters,sin gular value solutions of the strain compliance matrix difference can be used to obtain the generalized internal force damage index,in order to judge the damage location of the structure.Another damage index is the strain compliance matrix difference.Sin ce the strain compliance matrix is a diagonal matrix,the damage position and degree of the structure can be judged by the ratio of the strain compliance matrix difference to the non-damage strain compliance matrix.In this paper,the feasibility of two kinds of damage indexes is verified by MATLAB simulation.