Bridge Crane Structural Reliability Optimization Design Research

Traditional mechanical analysis methods are used in the design and evaluation of the metal structure of the crane,with simplification treatment of structure based on relevant empirical formulas,and most of the optimization designs are based on certainty.So although this treatment achieves the purpose of simplifying problems and improving efficiency,it often cannot accurately reflect the actual situation.Some uncertain factors can lead to reliability problems of crane structure.In this paper,the following works have been done:First of all,the parameterized crane girder model is established in ANSYS,and the stress and strain statics analysis are carried out on the most dangerous conditions,with obtaining the maximum equivalent stress and vertical direction of the maximum deflection of crane girder.It is found that there is a large design margin for its strength and stiffness check.Therefore,the deterministic optimization design is carried out in ANSYS optimization module(OPT),with the objective of minimizing the total mass.Next,by applying ANSYS probability design module(PDS),with consideration of such stochastic effects as geometry,material and load,the reliability analysis is performed for the main girder structure of deterministic optimization.At the same time,the reliability index is calculated in MATLAB.Then with results comparison,it shows that after deterministic optimization,the structural reliability of the main girder does not meet the design requirements.Finally,according to the robust reliability optimization design theory,the model of robust reliability optimization for the main girder structure is established,on the basis of sensitivity addition as additive objective function.The robust reliability optimization design of main girder structure is carried out by using the optimization toolbox and genetic algorithm in MATLAB tool.By comparison,the strength,stiffness and reliability index of the main girder structure after optimization design,can meet the design requirements.And at the same time,it achieves weight reduction of 3.4% for the main girder structure,with ensuring some robust design parameters.