大型铝合金薄壁件加工过程模态试验及有限元仿真

2019-02-18

作者：廖其刚1，樊海琴2，葛英飞2，刘钢3 单位：1贵州航天风华精密设备有限公司；2南京工程学院；3上海拓璞数控科技股份有限公司

摘要：通过锤击激振法模态试验和有限元仿真对大型铝合金薄壁件铣削时的动态特性进行了研究。结果表明，第1阶固有频率为372.6Hz，因此当刀具齿数一定，在选择机床主轴转速时，应避开大型铝合金薄壁件的1阶固有频率以避免铣削过程中发生共振。有限元仿真分析表明，第1阶模态表现为弯曲变形，第2阶模态表现为扭转变形，第3阶模态表现为二阶弯曲变形，第4阶模态表现为二阶扭转变形，第5阶模态表现为弯曲与扭转叠加变形，最大变形量出现在第4阶。有限元分析还发现，有辅助支撑装夹下铝合金薄壁件的固有频率比无辅助支撑装夹下的固有频率增大了10%，而最大变形量则降低了10%，且无论是否加辅助支撑，铝合金薄壁件的振动形态和趋势以及最大变形量发生的位置不变。

关键词：铝合金；薄壁件；铣削；模态分析；有限元分析

中图分类号：TG54；TH162文献标志码：ADOI：10.3969/j.issn.1000-7008.2019.02.014

Modal Analysis of ThinWalled Aluminum Alloy Parts by Experiments and

Finite Element Analysis

Liao Qigang，Fan Haiqin，Ge Yingfei，Liu Gang

Abstract:The modal analysis of thinwalled aluminum alloy parts is carried out by experiments and finite element analysis.The results show that the first natural frequency of thinwalled parts is 372.6Hz，and the spindle speed corresponding to this frequency should be avoided during milling in order to avoid the cutting resonance.The first order is bending deformation，the second order is torsional deformation，the third order is two order bending deformation，the fourth order is two order torsional deformation and the fifth order is superposition deformation of bending and torsion.Among the five order modal shapes，the maximum deformation appears in the fourth order.Using this finite element model，the model of thinwalled aluminum alloy parts with auxiliary supports is predicted.The results show that the natural frequency of the thinwalled aluminum alloy parts with auxiliary support is increased by 10%，and the maximum deformation is reduced by 10%.The results also show that the mode shapes of thinwalled parts is unchanged，whether there is auxiliary supports or not.

Keywords:aluminum alloy；thinwalled parts；milling；modal analysis；finite element analysis