基于测试与仿真的机床整机动态特性分析

Dynamic Characteristics Study on Entire Machine Tool Based on Test and Simulation

建立数控机床整机系统有限元模型,对于预估和优化机床的性能有着重要的意义。但是,由于整机系统结构复杂以及存在各种形式的结合面,因而很难直接建立反映实际的有限元计算模型。文中以沈阳机床集团某立式加工中心为例,研究了数控机床整机系统有限元建模方法。首先,在保证力学关系不变的情况下,对整机系统进行了物理模型的简化。其次,在有限元模型的固定和滑动结合部中引入接触区域分布设置弹簧来模拟结合面的法向和切向刚度。最后,以测试的模态参数为基准,修正不准确的有限元模型,使模型的频率误差小于15%,得到可以反映实际动态特性的有限元模型。

The model established by finite element method had inportant significance in estimating and optimizing theperformance of NC machine tool system. However, it was not suitable for simulation directly on account of complex structure and various forms of contact faces. In this paper, finite element modeling method was studied taking a verticalmachine center of Shenyang Machine Tool Group as an example. The structure of the components was simplified under the premise of keeping the dynamic relationship. In the building proeess, distriht, tion placed springs was used tosimulate the normal and tangential stiffness property of the fixed and sliding junction. The model is evah,ated and corrected with experimental results by modal testing on machine tool in which the natural frequencies and the shape ofvibration modes are analyzed. And its frequency errors reached less than 15% through modification. Then it could trulyreflect the actual dynamic characteristics of the machine tool.