【作者】 朱思洪； 李军芳； 王晖云； 周永清；

【Author】 Zhu Sihong Li Junfang Wang Huiyun Zhou Yongqing (College of Engineering, Nanjing Agricultural University, jiangsu Nanjing 210031, China)

【机构】 南京农业大学工学院；

【摘要】 以VH-25型高速精密压力机为例,建立了床身、底座和工作台的有限元分析模型,通过自由模态分析,得到各自的前5阶非刚体模态频率,分析结果表明,该压力机床身和底座的低阶模态频率很接近,容易引起二者之间的共振。用ANSYS中的弹簧-阻尼单元COMBINE14模拟床身、底座和工作台之间的螺栓结合部,建立了组合结构的有限元分析模型,对组合结构进行了模态分析,并将用该模型分析得到的组合结构模态频率和实验模态频率进行了对比,两者具有较好的一致性,说明结合部的处理方法是合理的,所建立的组合结构有限元分析模型可靠。在此基础上,提出了VH-25型高速精密压力机机体的六种改进设计方案。对仿真结果的对比分析发现,在床身下部距原有筋板0．40m处增加一条筋板,并将底座内侧壁的厚度增大0．01m,可以显著改善该压力机的动态特性,避免由于床身和底座低阶模态频率接近,以及组合结构一阶模态频率与电动机工作频率接近而可能引起的共振,提高压力机的动态性能。更多还原

【Abstract】 In order to reduce the vibration of high-speed press, and enhance its work performance, the dynamic characteristic of its main parts and combined structure was analyzed. The finite element models of the lathe bed, the base and the workbench were built up using ANSYS. The first five modal frequencies were extracted by free modal analysis. The analysis results showed that the low frequencies of the lathe bed were approximate to those of the base, which would cause vibration resonance easily. The bolt joints were equivalent with the model made of linear spring-damper element COMBINE 14 between two nodes in ANSYS. Using these elements, the finite element model of the combined structure was built up. The modal parameters obtained by theoretic modal analysis were basically coincided with those obtained in modal experiment. This proved the rationality of the model of the bolt joints and the reliability of modal analysis results of the combined structure. Six different design improvements to the press structure were brought out and the correspondent modal analyses were carried out. The simulation research shows that the low order frequencies of the lathe bed and the base are far away from each other and the first order frequency of the combined structure is far greater than that of the electromotor when another clapboard 0.40m apart from the original one of the lathe bed is added and the thickness of the wainscot in the base is increased by 0.01 m. This reduced the probability of the vibration resonance.更多还原