轴系横向裂纹模型对其扭转剪应力的影响

本文对轴系横向直线裂纹和半椭圆裂纹两种模型的裂纹最深点处的应力强度因子 进行了推导,以研究不同模型对轴系扭转剪应力计算的影响。计算表明：采用这两种模型计算扭转剪应力时其相对差值会很大,最大可达60％左右。但在特定范围内差值很小。本文定义了该两种模型扭转剪应力的临界相对差值 ,确定了不同裂纹深度比 （ ）所对应的临界椭圆参数 ;拟合了不同裂纹深度比 （ ）下临界椭圆参数 的计算公式,为科学选取模型提供了理论依据。

Influence of transverse crack model on shafting's torsional shear stress

In order to study the influence of the transverse crack models on the shafting`s torsional shearing stress calculation, this paper deduces and analyzes the mode Ⅲ stress intensity factor in the crack deepest point of the transverse straight crack model and the transverse semi-elliptical crack model. The calculating result indicates that: the relative distinction of the torsional shearing stress by using these two models might be great and the biggest distinction can reach about 60%. But in a particular range, the distinction is rather small. In addition, this paper has defined a critical relative distinction concerning the torsional shearing stress of the two models, and then confirmed the corresponding critical elliptical parameters with different crack depth ratios. At last, this paper has fitted an equation, with regard to the critical elliptical parameters under different crack depth ratios, so as to build up a theoretical background for scientifically selecting models.