紧螺栓联接疲劳强度可靠性设计中的几何效应及其参数分布

螺拴的几何参数是影响螺栓联接疲劳强度的重要因素。本文对五种规格的螺拴用投影-拟合法进行了大样本抽样测试并作出统计处理。分析结果说明,螺纹小径d₁,螺纹根部圆角半径r和螺栓头部圆角半径R均服从正态分布,并得到了相应的分布参数,从而为螺栓联接的疲劳强度可靠性设计,合理考虑几何效应以及螺栓的可靠性指标的制订提供了依据。

Geometrical Effect and Its Parameter Distribution of the Preloaded Bolted Joints on the Reliability Design of the Fatigue Strength

The geometrical parameters of a screw bolt are important factors that affect the fatigue strength of the bolted joints. Therefore, the author has made selective measurements and statistical treatments from among a large number of samples of five models of screw bolts by way of project-analogue method. The analysis result has indicated that the minor diameter d1, the round radius at the bottom of the scr-ewr and the round radius under the head of the bolt R are distributed according to the normal. From the above conclusion, We have determind their distributive parameters. Hence, a sound basis is provided for the reliability design of the fatigue strength of the bolted joints, the reasonable consideration of its geometrical effect and the formulation of the reliability index of the screw bolt.