Structural Optimization Of Foundation Parts Of Deep Hole Machine Tool Based On Stochastic Finite Element Method

With the development of deep hole machining technology,deep hole machining machine tool develops towards the direction of high precision,high efficiency and intelligence.As a key component of deep-hole machine tools,the spindle box's quality and its static and dynamic performance during operation will have an important impact on the machining performance of deep-hole machine tools.Traditional deep-hole machine tool base parts usually adopt experience design or analog design in structural design,which leads to the spindle box structure with redundant quality,bulky volume and certain processing difficulty,thus affecting the dynamic and static performance,process performance and processing performance of the machine tool.To solve above problems,this article with ZWKA2108 deep hole machine tool spindle box as the research object,through the establishment of three-dimensional model,finite element static and dynamic analysis of the spindle box,on the basis of the obtained by parameter correlation analysis of the parameters of the spindle box had a greater influence on the quality,optimized by response surface was optimized after the structure dimension of the axle box and static and dynamic performance.Finally,the reliability analysis of the optimized spindle box was carried out to verify the rationality of the optimized main axle box structure qualitatively and quantitatively,thus providing a certain reference basis for the subsequent research on key structural parts of machine tools.The research contents include:(1)Based on Solidworks and ANSYS Workbench,the finite element statics analysis and modal analysis of the spindle box were carried out.A THREE-DIMENSIONAL solid model of the spindle box was established in Solidworks and parameterized,which was imported intoANSYS Workbench for finite element static and dynamic analysis,to obtain the stress and deformation cloud map of the spindle box,and extract the first six natural frequencies and mode diagrams of the spindle box.The analysis of the results shows that the original design of the spindle box has large redundancy in stiffness and strength,so there is room for further optimization design.(2)Based on response surface method,the structural optimization design of headstock is carried out.Using the optimization design module in ANSYS Workbench software,the optimization objectives were established with the spindle box quality and first-order natural frequency as the objectives,the maximum stress,maximum deformation and first-order natural frequency as the constraints,and the key geometry size of the spindle box as the design variable.Through parameter correlation analysis,the size parameters that have a greater influence on the optimization target are selected,and the response surface model of the optimization target function is established.Based on the response surface model,the multi-objective genetic algorithm is selected for calculation.The results show that under the premise of satisfying the working performance of the spindle box,an ideal structure size is obtained,the mass of the main axle box is reduced by 6.431% after optimization,and the optimization purpose of structural lightweight is achieved.(3)The reliability analysis of spindle box is carried out based on stochastic finite element method.On the basis of optimizing the structure of the spindle box,six sigma reliability modules in ANSYS Workbench to the optimized quantitatively the reliability analysis of the spindle box,by defining the failure limit state function of the spindle box structure,material properties,geometrical size,load is considered as a random variable and the size of the outside accord with normal distribution,using Monte Carlo method to calculate,respectively,to optimize the static strength of the axle box to have the away,static stiffness and dynamic stiffness reliability analysis.The results show that the reliability of static strength,static stiffness and dynamic stiffness of the main axle box after optimization meets the requirements,and the rationality of the optimized design of the spindle box is verified quantitatively.