基于赫兹理论的销轴连接修正设计方法研究

Modified design method of pinned connection based on Hertz theory

工程设计中销轴连接的接触应力峰值及应力分布模式大多以赫兹接触理论为准则进行分析。一般认为,作用于销轴的荷载在耳板范围内均匀分布或以等效集中力形式作用于耳板中线处,但实际工程中销轴连接的边界条件并不完全符合赫兹理论的假定。为得到更为精确的销轴连接应力计算式,在有限元模型中各相关参数的设置得到验证后,对销轴连接进行了参数分析。研究摩擦系数、耳板厚度、耳板间隙和销轴直径等参数对处于弹性工作状态的销轴连接的接触应力数值及其分布规律的影响,并对大量有限元分析结果进行拟合,提出了基于赫兹接触理论修正的销轴局部接触应力峰值计算式及销轴的最大弯曲应力计算式。在建议的尺度范围内,采用修正后的应力计算式的计算结果和有限元分析结果吻合较好,且具有较高的精度,可为工程应用提供参考。

The analysis of the contact stress and stress distribution pattern of the pinned connection are mostly based on the Hertz contact theory in engineering design. It’s generally considered that the transmission load acting on the pin is evenly distributed within the lugs and acts on the midline of the lugs in the form of equivalent concentrated force. Actual boundary conditions of the pinned connection are not fully consistent with the assumption of Hertz theory. To obtain more precise stress of the pinned connection,the influences of the parameters such as friction factor,lug thickness,clearance and diameter of the pin on the contact stress and stress distribution of the pinned connection in the elastic state are studied after the validations of FEM parameters. The formulas for calculating the local contact peak stress and the maximum bending stress of the pin based on the modified Hertz theory are proposed by a large number of finite element model analyses. Within the proposed ranges of parameters,the results of these formulas are in good agreement with the finite element analyses results. It provides a reference method to calculate stress of pin connections for engineering design.