The Research Of Two-stage Damage Detection Method Based On Improved Gravitational Search Algorithm

With the development of science and technology,researchers have proposed many intelligent optimization algorithms which are widely used in various fields.In these intelligent optimization algorithms,the Gravitational search algorithm(GSA)has gained the attention of many researchers.As a new intelligent optimization algorithm,the gravitational search algorithm has many advantages,such as simplicity in concept,convenient operation and high efficiency calculation.The algorithm has been widely used in practical engineering,such as unmanned aerial vehicle route planning,image processing,etc.At the same time,in the process of the development of structural damage identification technology,the finite element model technology has been continuously researched and developed.Although the finite element model technique has been implemented,the traditional algorithm is still unable to avoid the problems of early precocity and low computational efficiency.In this context,the gravitational search algorithm is improved from two aspects: the self-learning of gravitational search algorithm and particle update.At the same time the two-stage damage identification model is applied in the improved gravitational search algorithm.The main research work of this paper is listed as follows:1)Firstly,the definition of structural damage is explained,and the four stages of structural damage and the method of damage identification are summarized.Secondly,the method of finite element model and intelligent optimization algorithm is introduced in this paper.2)The current research and development direction of gravity search algorithm is briefly introduced.The balance between exploration and development in intelligent optimization algorithm is discussed.Then,the operation mechanism of gravity search algorithm based on the basic principle,algorithm realization and algorithm flow in the gravity search algorithm is introduced in this paper.3)In many damage detection indexes,the three kinds of structural damage identification based on element modal strain energy index definition are introduced in detail.The numerical simulation of structural model is established for comparing three indexes,so as to select indicator of the locating structure damage stage.4)Based on original gravitational search algorithm mechanism,the information to particles in the solution space is received from two sides: other particles in the solution space and its own history.Comparing the latest fitness of the particles with the former one,a better fitness of particles is selected for the next iteration.From update algorithm iteration,we proposed an adaptive inertia weight.The algorithm has the good balance between the development ability and the exploration ability in the whole process for dynamic change.Based on the above two improvements,the performance optimization of the algorithm is verified by three test functions.5)Given by the weaknesses in the results of numerical simulation based on gravitational search algorithm: low operation efficiency and mistakes in locating damage unit number,two-stage structure damage identification method based on the improved gravity search algorithm is coming up.Finally,we apply the two-stage structure damage identification method based on the improved gravity search algorithm to the structural damage identification numerical examples.The results of numerical simulation show that the further-improved gravity search algorithm has better operation efficiency and higher precision damage identification ability.The good performance of the method in damage detection shows the method has a certain engineering application potential.