面向机床整机动态性能的立柱结构优化设计研究

Research on Optimization of Column Structure Design for Dynamic Performance of Machine Tool

针对某机床结构薄弱件立柱的结构优化设计,提出了一种基于拓扑优化、筋板形式选择与布局以及尺寸优化的结构设计方法。首先利用有限元法(finite element analysis,FEA)对机床整机进行动力学分析,模态分析与谐响应分析结果表明立柱为影响整机动态性能的关键结构件。然后以立柱结构为优化目标,对立柱进行拓扑优化,根据拓扑优化的材料分布情况设计了立柱的最优基本结构形式,再通过选择抗弯、抗扭刚度较好的W类型筋板进行布局与尺寸优化,得到了最终的立柱优化结构。最后对优化的立柱结构进行验证,分析结果表明:该结构设计方法有效地改善了整机的动态性能,在立柱质量减轻的前提下,优化后的整机前六阶固有频率均得到了不同程度的提高,其中一阶固有频率提高了10%以上;并且机床在x方向上的最大共振峰值下降了49.8%,y方向下降了70.1%,z方向下降了66.2%。

Aiming at the optimization design of machine tool column structure which is weakest link, a method is presented based on topology optimization, ribs form selecting and layout, and size optimization. From kinetic analysis of the machine tool by finite element analysis（FEA）, modal analysis and harmonic response analysis illustrate that the column structure is the key part to affect the dynamic performance of the machine tool. Taking the column as optimization object, its basic structure is designed by material distribution of topology optimization. Selecting the W ribs which have well bending stiffness and torsional stiffness to layout and optimize its sizes, the column structure is finally optimized. Analysis results demonstrate that the method effectively improve dynamic performance of the machine tool. On the premise of the column mass does not increase, 6 nature frequencies of the machine tool are increased with different degrees. The first nature frequency is increased by about 10%. The biggest resonance peaks of the machine tool in x direction are reduced by 49.8%, y direction 70.1%, z direction 66.2%.