Study On Cable Stayed Bridge Damage Identification Based On Wavelet-Bacterial Foraging Optimization Algorithm

With the development of science and social economy,the structure of civil engineering is becoming more complicated and diversified.Cable-stayed bridge structure is widely used in engineering because of its good mechanical performance,strong spanning ability,rich mod-eling and strong seismic resistance.In the process of using various civil engineering structures,damage is usually caused by loads,the environment and various emergencies.And then the damage lead to catastrophic accidents.So if the structural safety condition is evaluated by the way of identification and diagnosis of structural damage in advance,disaster can be avoided and people's life and property safety can be guaranteed.It has great significance to study the damage identification of structures and discover the damage of structures in time.Based on the research of structural damage theory at domestic and abroad,it is found that wavelet analysis has good adaptability and time-frequency analysis ability in signal anal?ysis.The singular point of the signal can be found accurately by using the maximum modulus point of the wavelet coeff-icient graph,which can be used to process the structural dynamic signal.The bacterial foraging algorithm is a kind of colony evolution algorithm,which has the ability of rapid convergence and global optimization.In this paper,the advantages of wavelet and bacterial foraging algorithm are combined and a structural damage identification method based on wavelet and bacterial foraging algorithm is proposed.Firstly,the damage location was determined by continuous wavelet transform of the curvature mode of the structure,and then the damage degree was identified by bacterial foraging algorithm.In this paper,damage identification of cable-stayed bridge structures is studied based on wavelet-bacterial foraging algorithm.Firstly,the finite element model of cable-stayed bridge with damage element is established and the curvature mode of cable-stayed bridge is extracted.Secondly,the curvature mode is transformed by continuous wavelet transform to obtain its wavelet coefficient graph,and the damage element is found by using the maximum point of the modulus in the graph to complete the damage location in the first stage;Then,on the basis of determining the damage location,the objective function is constructed by using the struc-tural frequency and the element modal strain energy.The iterative optimization is carried out by using the bacteria foraging algorithm to calculate the damage degree of the damage ele-ment.In this paper,combining with particle swarm optimization,which can constantly update particle velocity and position advantages through the best position experienced by the whole population,the bacterial foraging algorithm is improved and an optimized bacterial foraging algorithm is established.Through the numerical simulation of cable-stayed bridge,the results show that the optimization algorithm of bacteria foraging has obvious improvement in the early convergence speed and program running time,and the damage degree can be accurately solved.Therefore,the wavelet-bacterial foraging algorithm and its optimization algorithm proposed in this paper are correct and feasible.It can provide a reference for practical engi-neering structure damage identification.