机械螺栓法兰连接的有限元力学模型比较研究

Comparative evaluation of finite element models for mechanical structures with bolted joints

机械螺栓-法兰连接结构中存在着复杂的接触、摩擦和预紧等非线性因素。螺栓-法兰连接结构的有限元力学模型应当充分包含这些因素。首先介绍了连接结构接触分析的有限元法理论,然后比较研究了二维轴对称力学模型和三维实体模型在螺栓-法兰连接结构建模中的差别,之后研究了温度载荷法、过盈配合法和等效外载法等三种不同的螺栓预紧力建模方法。计算结果表明:二维模型在处理螺栓-法兰连接结构上计算耗费小,但计算精度较三维模型差别较大,结果粗糙;三种预紧力模拟方法都能模拟螺栓预紧载荷,但在适用范围、等效方法和计算精度等方面有区别。

Contact,friction and preload are the most important factors for modeling mechanical structures with bolted joints. Reasonable finite element models should fully consider these factors. A contact finite element analysis method was first introduced. A comparison between 2D axisymetric and 3D solid finite element analysis type was present. Different methods ,such as effective temperature ,effective force and interference fit,were used to modeling pretensions of bolt under tight moments. It is shown that 2D analysis has less computation efforts than 3D also with less precision. Three preload methods can model the given pretension but there is much difference in application scope ,effective technique and computation precision.