Damage Identification Of Suspension Bridge Structure Based On Wavelet-artificial Immune Algorithm

Suspension bridge structure due to the the light quality and high strength has been more and more used in the construction of large span.Suspension bridge structure in using will be affected by factors such as environments and loads which causing the damage and a threat to the safety of the structure of suspension bridges,sometimes can even cause catastrophic accidents.Therefore,the study of suspension bridge structure damage identification has significant theoretical and engineering application value.Wavelet analysis is a time-frequency analysis method which has the multi-resolution analysis function and can effectively identify the singularity of the signal,thus it can identify structural damage location according to its characteristics.Artificial immune algorithm is combined with the traditional artificial intelligence algorithm and the advantages of the mechanism of biological immune system.It has set up a global search ability intelligent algorithm and has the very strong information processing capability,which can be applied to the degree of structural damage identification.The thesis takes the suspension bridge structure identification problem as research object,combining wavelet analysis and artificial immune algorithm,has established a kind of damage identification method of suspension bridge structure based on wavelet-artificial immune algorithm.The thesis has based on the wavelet analysis to identify structural damage location,using artificial immune algorithm to construct the objective function.The function has used structure damage location and damage unit number as the input parameters,and figured out the principle of wavelet-artificial immune algorithm to identify structure damage by compiling the degree of artificial immune algorithm program identifying the structure damage.In order to identify suspension bridge structure damage problem better,this thesis has used Euclidean distance and Immune Genetic Algorithm respectively to optimize the traditional artificial immune algorithm,which can guarantee there is no local optimal solution in the process of the algorithm solving and searching.The optimized artificial immune algorithm calculation convergence speed is faster and more efficient.This paper established a finite element model of suspension bridge structure,got the strain modal by calculation and analysis,and used MATLAB to establish the procedure of artificial immune algorithm.Modulus maxima of wavelet coefficient figure are structure damage location.It used structure damage location and damage unit number as the known parameters of artificial immune algorithm procedures and program output parameters are the damage degree of structure.Besides it compared and analyzed the computational efficiency of Euclidean distance and immune genetic algorithm.This paper studied 2 and 3 in damage problems of the single span and three span suspension bridge,established structure finite element model and carried out numerical simulation analysis,applied the wavelet analysis to identify the damage location of the suspension bridge structure.It applied the optimized artificial immune algorithm to identify the damage degree of structure on the basis of damage location and damage unit number,and the numerical simulation verified the effectiveness of the method.This paper established the wavelet-artificial immune genetic algorithm which can effectively identify the damage of suspension bridge structure and it has a certain reference value for engineering application.