有限元分析的C型预弯机轻量化设计

Lightweight design on C type pre-bending machine structure based on FEA

针对一款C型预弯机,为检测其强度与刚度要求,避免出现安全系数过高的问题,将其模型简化后建立有限元模型,初步有限元分析显示最大应力为261.17MPa,超过材料屈服极限要求且集中在机身喉口处。为进一步加强预弯机强度,避免出现结构笨重的问题,根据初步分析结果设置正交试验,将前后两种不同直径的拉杆、侧板、八角筋板和上横梁焊件内部筋板的结构参数作为变量,进行了参数化建模,得到16组有限元分析计算结果。基于最小二乘法在SPSS中计算得到预弯机整体变形、应力及重量与机身结构参数的回归系数与方程,并建立了优化目标函数的数学模型,最终通过Matlab优化工具箱计算出了试验后的轻量化参数。结果使得预弯机重量降低17900kg,应力减小46.67MPa,轻量化比例为7.34%。

For a type of C pre-bending machine,in order to test its strength and stiffness requirements and avoid the problem of high safety factor,the model was simplified,and the finite element model was established.However,the preliminary finite element analysis showes that maximum stress 261.17 MPa exceedes the material yield limit requirements and concentrates at the throat of fuselage.In order to further strengthen the strength of pre-bending machine and avoid the problem of heavy structure,according to the preliminary analysis result, the orthogonal test was set up,and the structure parameters of two different diameters of pull rods,side plates,octagonal stiffener and in- ternal stiffener of upper beam weldment were taken as variables.Then,the parametric modeling was conducted,and the results of sixteen groups of finite element analysis were obtained.Based on the least square method,the regression coefficients and equations of the whole deformation,stress and weight and structural parameters of fuselage were calculated in SPSS,and a mathematical model was established to optimize the target function.Finally,the lightweight parameters of test were calculated by the Matlab optimization toolbox.The results show that the weight and stress of pre-bending machine reduce 17900kg and 46.67 MPa respectively,and the lightweight ratio is 7.34%.