柔性化夹具静动态特性分析及拓扑优化

Static and dynamic characteristics analysis and topology optimization of flexible fixture

针对汽车发动机缸盖、变速箱阀体全自动化混合生产线,设计柔性化夹具来满足CNC高精密加工以及快速换产的要求。建立夹具系统三维模型,并利用ANSYS对夹具系统在不同加工工况载荷下进行静态性能分析;从分析结果判断出影响夹具性能的关键结构,并对其进行拓扑优化设计,实现夹具整体减重39.25 kg。然后对改进后夹具模型进行验证分析,发现最大变形量减少为0.0045199 mm,满足设计指标0.005 mm;最后,对现有夹具系统进行模态实验和CAE模态分析,发现夹具系统在Z向受到低频激振力时,容易发生共振,该频段为70 Hz?110 Hz,在加工过程中需要控制刀具加工频率避免发生共振。

The flexible fixture is designed to meet the requirements of CNC high precision machining and rapidlyswitching for automobile engine cylinder head and gearbox body.Establishing a three-dimensional model of the fixture system,and the static strength analysis of the fixture system under different processing conditions was carried out by using ANSYS.The key structure affecting the performance of the fixture was judged from the analysis results,and the topology optimization design was carried out to reduce the weight by 39.25 kg.Then the improved fixture model is verified and analyzed,and the maximum deformation is reduced to 0.0045199 mm,which satisfies the strength design index of 0.005 mm.Finally,both the CAE modal analysis and the modal experiment are conducted on the original model.Resonance is easy to occur when the flexible fixture is subject to low-frequency excitation force in the Z direction,the frequency band is estimated to be 70 Hz^110 Hz,which should be avoided during the machining process.