Method For Determining Important Monitoring Members Of Space Steel Structure Based On Multiobjective Genetic Algorithm

Obtaining the response data of important parts in the structure through means of structural health monitoring,and then analyzing the local structural data to understand the overall safety status of the structure is an important method to ensure the safety of the engineering process of the structural service process.However,the actual structure is subjected to complex external actions.The position of important structural members analyzed from different angles is different,which makes it difficult to arrange the measuring points,which in turn affects the comprehensiveness of evaluating the overall state of the structure based on the limited measuring point data.After comprehensively considering the differences of important members analyzed from different research angles,the important members are selected through optimization and comparison,and then the overall state of the structure is inferred based on the finite member data.Therefore,the selection method of important members comprehensively considering multi-angle analysis is proposed,and the response information of important members is used to realize the assessment of the overall safety state of the structure.Main research work of this article starts from the following three aspects:Study on the importance of members considering different angles.Consider the angles of stiffness,stability,energy consumption and strength,analyze the impact of the failure of the member at different positions on the structure,construct the evaluation index,and analyze the changes in the importance of the member.When considering stiffness,stiffness matrix is applied to construct vulnerability index.When considering stability,stable bearing capacity is applied to construct stable bearing capacity degradation index.When considering energy consumption,strain energy is applied to construct strain energy dissipation index.When considering the strength,stress ratio is applied to construct the average stress ratio index.Analyze the difference in the importance of members at the same angle and different positions,the difference in the importance of the same member at different angles,and the difference in the change trend of the importance index of members between different angles.Through the simulation analysis of K6 reticulated shell,according to different research objectives,the importance of the members is comprehensively analyzed,and the validity of the importance evaluation index is verified.An important member selection method based on multi-objective genetic algorithm.Establish the principle of selecting members,namely,select members that have a great influence on the structure.On the basis of the selection principle,two objective functions are determined based on the importance index of members and mutual information entropy.Based on the optimization model of the NSGA-II algorithm,the {0,1} coding method is used to represent the scheme of selecting the rod.The determined objective function is taken as the optimization objective in the algorithm.The algorithm is used to optimize the coding of the member program,and the optimized program code is obtained,and then the position of the important member is determined.In addition,the crossover and mutation operators in the NSGA-II algorithm are improved to adapt to the optimization process.Finally,based on the four indicators of the important members of the existing K6 reticulated shell analysis,optimization analysis was carried out to determine the important member combinations corresponding to different numbers of members.Determination of the important members of the large shell steel structure of the Zhuhai Grand Theater.According to the characteristics of the strain measurement point arrangement of the health monitoring system of Zhuhai Grand Theater,70 rods in the large shell surface 3 were selected to analyze the importance of four different angles.Considering the difference in the importance of different angle members,based on the improved multi-objective genetic algorithm,different numbers of important members are selected to verify the effectiveness of the method in complex steel structures.The overall stress range of the structure is evaluated based on the stress of the important members,and the feasibility of the selection method of the important members mentioned in this paper is demonstrated.