基于正交试验的机床移动横梁多目标优化设计

MULTI-TARGETS OPTIMIZATION DESIGN FOR MOVING CROSSBEAM OF MACHINE TOOL BASED ON ORTHOGONAL EXPERIMENTAL METHOD

为了提高机床移动横梁静、动态综合性能,机床横梁必须具有合理的筋板布局和结构特性。建立了横梁振动力学模型,理论计算了横梁最大耦合变形量,在三维设计软件中对机床横梁进行三维建模,并使用Ansys对横梁进行静态、模态分析。文中以机床横梁质量、最大耦合变形、最大耦合应力、一阶固有频率作为评价机床横梁设计优劣的目标函数,以横梁筋板结构、筋板厚度,上导轨支撑筋板倾斜角度作为设计变量进行多目标优化设计。采用正交试验法,设计了3因素4水平的正交试验;运用综合平衡法确定最优水平,从而得出最优的试验方案。结果表明,横梁理论计算变形量与仿真分析值相近,且横梁"井"型筋板结构,筋板厚度25 mm,上导轨支撑筋板倾斜55°设计为最优方案,其中与原设计方案相比质量减轻了473 kg,横梁总形变减少了7.455%,一阶固有频率提高了2.956%。研究证明,采用正交试验法合理设计横梁试验因素与水平,可以以较少的试验次数获得最优的试验结果,说明正交试验法具有较高的工程运用性。

In order to improve a machine moving beam＇s comprehensive performances,which includes static and dynamic characteristics,it must have a reasonable beam ribs layout and structural properties. The crossbeam was simplified to get the mechanical vibration model,the maximum coupling deformation was solved by the theoretical calculation method. Using 3D software to establish the three-dimensional modeling of beam and ANSYS was used for static,modal analysis. Taking beam＇s quality and the maximum coupling deformation,the maximum coupling stress,the first-order frequency as objective functions to judge the merits and drawbacks of crossbeam＇s optimization,taking the crossbeam＇s rib structure,the rib thickness,the angle of support stiffened plate as design variables for multi-objective optimization design. Orthogonal experimental method was used to design the orthogonal experiment with three levels and four factors. Using overall balance method to chose the optimal level,and then getting the best test program. The results show that： Theoretical analysis and simulation results are very similar. the beam with ＂井＂type rib structure,rib thickness of 25 mm,the support stiffened plate tilted 55 ° design is the optimal solution.Compared with the original design,the beam deformation reduced by 7. 455% and the first-order frequency increased by 2. 956%,while the quality reduced by 473 kg. It shows that using the orthogonal experimental method to design reasonable levels and factors can achieve optimum results with fewer tests,and the orthogonal experimental method is valuable for engineering application.