Non-probabilistic Reliability Optimization Design Of Crane Structure

The traditional crane structure design is based on the deterministic parameters of the structure,without considering the uncertainty of the parameters.In actual engineering,the design parameters are uncertain variables,which leads to the error between the analysis results of the traditional design and the actual situation.Therefore,using reliability analysis to consider the uncertainty of design parameters makes the analysis result more realistic.For civil equipment such as cranes,it is difficult to obtain accurate analysis results based on the characteristics of high test cost and few parameter data samples,which depend on the probabilistic reliability theory of parameter distribution law.Therefore,this paper introduces the non-probabilistic reliability method,which can make up for the defects of probabilistic reliability,and only rely on small sample data to quantify the reliability of the structure according to the upper and lower bounds of uncertain variables.Therefore,this paper takes the main beam structure of bridge crane as the research object,and takes the non-probabilistic reliability index as the constraint condition of optimization analysis,which can not only meet the safety requirements of crane structure,but also realize the optimization goal of crane structure.In this paper,a double-layer nested optimization model with high accuracy is adopted.The outer layer of the model mainly searches for the optimal structural size of the bridge crane,and the inner layer calculates the nonprobabilistic reliability index of the bridge crane structure.In this paper,the whale algorithm is used as the optimization method of the outer layer of the model,which solves the shortcomings of the previous algorithm,such as complex programming and slow search speed,simple operation,fast optimization speed and few parameters to be controlled,and the spiral search mechanism is used to enhance the local search ability.It provides a new idea for the double-layer nested optimization method of crane structure.In this paper,the bridge crane structure is taken as the research object.In view of the characteristics of the crane structure,such as large strength margin and small stiffness margin,when establishing the constraint conditions of the optimization model,the limit state reliability index with minimum margin is taken as the constraint condition,which reduces the number of constraint conditions and the optimization time.Through the non-probabilistic reliability optimization of engineering examples,it is shown that although deterministic optimization can reduce the structural quality to a certain extent,it can not meet the reliability requirements.Therefore,the non-probabilistic reliability optimization method can not only effectively reduce the weight of the main girder structure and achieve the optimization goal,but also ensure the reliability constraints and structural safety.The non-probabilistic reliability optimization method adopted in this paper not only considers the small sample of structural parameters,but also considers the effectiveness of the optimization method,which provides a new idea for the optimal design of crane structure.