The Lightweight Design Of The Boom Of Mechanical Excavator Based On Surrogate Model Technology

Due to the low requirement for blasting effect,well-adjusted,high bucket fill factor,mechanical excavator is widely used in open coalmining.With the continuous development of economy,the demand of nation for coal,mineral resources becomes more and more.So it puts forward higher requirements on mechanical excavators.The traditional design method redundantly considers the safety factor,which result in too much weight,lower reliability,depressed work performance.Therefore,we urgently need a new design method to lighten the weight of mechanical excavator.Taking taiyuan heavy industry WK-55 mechanical excavator boom as the research object,the boom of excavator was lightened weight taking into account static strength constraint and fatigue life constraint.The main research content is as follows:The discrete element software EDEM was used to acquire shovel bucket digging resistance curve in the mining process and the mechanics analysis of excavator working device was made based on resistance curve in order to acquire the overall stress curve of boom.Then,boom was simplified as the beam unit so as to drawing bending moment diagram and axial force diagram and the maximum bending moment cross section and the maximum axial force cross section were determined.Finally,the largest bending moment of the maximum bending moment cross section and the largest axial force moment of the maximum axial force cross section were determined.The finite element analysis software ANSYS Workbench was used to acquire the maximum stress moment according to the largest axial force moment and the largest bending moment.After acquiring the maximum stress moment,The finite element analysis software ANSYS Workbench was used to do statics analysis and fatigue life analysis and we obtained the maximum stress value and fatigue life value.The stress nephogram and the fatigue life nephogram of boom were analyzed for further optimization.The lightweight mathematical optimization model of boom was determined and Latin hypercube experimental design method(LHS)was used to select the training points and test points for building surrogate model.According to evaluation criteria,the building surrogate model type of quality,stress and fatigue life was determined.The genetic algorithm was used to find the optimal structure parameters which met lightest quality of boom in the premise that boom satisfied stress constraints and the fatigue life constraint.Finally,the modified boom met design requirement.The topology optimization technology was used to optimize the boom structure after optimization based on surrogate model technology.Based on topology optimization results,boom was further improved and quality was further reduced.Finally,the further modified boom was verified and result complied with design requirement.