基于面压不均匀分布的结合部动力学建模研究

提出了一种基于结合面压力不均匀分布的螺纹固定结合部动力学建模方法。首先,利用Ansys对施加预紧力的装配体整机进行静力学分析,提取结合面处的节点、单元信息及压力分布,基于节点间距离最短的原则对上、下结合面中的节点进行匹配,在匹配好的两节点间建立Matrix27刚度和阻尼单元,以此来描述结合部的动力学特性;其次,基于结合面压力分布及Yoshimura法,求解Matrix27单元中的刚度系数和阻尼系数;最后,将结合部与零部件有限元模型综合成整机有限元模型。对比前四阶理论模态与试验模态可知:理论模态振型与试验模态振型相似且一一对应,理论固有频率与试验固有频率间的误差在0.7%～7.2%范围内,从而验证了该建模方法的有效性。

Study on Joint Dynamic Modeling with Uneven Pressure Distribution

This study proposes a dynamic modeling method based on the threaded tightening joint part with the inhomogeneous distribution of pressure. Firstly, ANSYS (a software) is used to fully analyze the statics of the assembly part. The node, element information and pressure distribution at the joint surface are extracted. The nodes in the upper and lower joints are matched based on the principle of the shortest distance between nodes. The Matrix27 stiffness and damping elements are established between two matching nodes to describe the dynamic characteristics of the joint. Secondly, the stiffness coefficient and damping coefficient of Matrix27 unit are calculated based on the joint surface pressure distribution and the Yoshimura method. Finally, the finite element models of the joint part and the individual part are integrated into the finite element model of the whole machine. Compared with the theoretical modes and experimental modes on the first four stages, the shapes between the theoretical and experimental modes are similar and correspond to each other. The error between the theoretical natural frequency and the experimental one is in the range of 0.7% to 7.2%, validating this modeling method.