Study On Damage Detection Of Local Structure Of Bridge Based On Piezoelectric Materials

With the increase of service time,if early damage of structural materials can not be detected in time,that will continuously change the strength and stiffness of structures,and then cause cumulative damage to structures,resulting in sudden failure of structures.Therefore,it is of great theoretical and practical value to identify the early and potential damage of structural materials in a timely and accurate manner.With the emergence of piezoelectric smart materials,its unique piezoelectric properties provide a feasible,accurate and efficient structural damage detection method for structural damage detection.On the basis of the existing research results,this paper summarizes the research of many experts and scholars on piezoelectric materials since the world,and spends a lot of space to introduce the piezoelectric materials.Then,the mechanical impedance expression of the piezoelectric material is given in the coupling system of "piezo main body",which provides a theoretical basis for the damage detection based on the piezoelectric material..Then,the ANSYS finite element software is introduced,and the numerical simulation problems and steps of the structural damage detection based on piezoelectric materials by ANSYS Mechanical APDL are also introduced.In this paper,a detailed local model based on ANSYS finite element software is established by combining the actual problems of concrete beams which are separated from concrete and damaged by concrete beams and concrete beams,which appear in the project.The different working condition information is established,and the influence of the impedance signal curve of the PZT piezoelectric sheet under different working conditions is considered respectively.By using two different damage index coefficients,the least square fitting curve is used to study the variation of the coefficient of damage index by using the MATLAB software.The main conclusions are as follows:(1)for the resistance curve of the PZT1 piezoresistance of different steel plate and concrete,it can be obtained with the increase of the degree of separation between the steel plate and the concrete,and the impedance curve of the piezoelectric sheet also decreases as a whole.(2)by establishing the damage index RMSD and CC,it is found that the mean square root deviation RMSD value is two times of function change when the shear nailand the concrete separation depth is linear,while the RMSD value presents a change law when the degree of debonding of the concrete and the steel plate is linear.(3)for the research of concrete containing cracks,it is found that when the depth of the crack does not exceed a certain depth,it has little effect on the force wave,but the depth of the crack will have a great influence on the propagation of the force wave when it exceeds a threshold value.The result is that the amplitude of the signal curve is smaller and the time required for the propagation will also increase,which leads to the signal curve to be directed.The right occurrence is lagging.Based on the positive and inverse piezoelectric effect of piezoelectric materials,this paper combines the problems of the engineering practice to make a good conclusion,which has laid the feasibility for the application of piezoelectric materials to practical engineering.