螺栓预紧连接可靠性灵敏度分析

Reliability sensitivity analysis of bolt pre-tightening connection

针对传统的螺栓预紧失效分析方法认为螺栓参数是确定的,而在实际螺栓连接中,各种结构参数的随机性将造成较大的分析误差的问题,考虑随机因素的影响,建立了一个螺栓预紧失效行为的有限元分析模型,以螺纹处的应力值是否超过屈服强度为判别条件进行可靠性分析,计算各参数对连接结构失效现象的灵敏度。研究结果表明:螺栓大径的变化对螺栓静强度失效的现象影响最大,材料的泊松比对其影响次之;螺栓连接的可靠度会随螺栓牙型角、螺距和材料泊松比的增大而增加,随螺栓大径以及材料的密度、弹性模量的增大而减小。

In bolt connection,excessive pre-tightening force will make bolts fail in case of accidental overload.Traditional method of bolt pre-tightening analysis considers that the parameters are determined,but the parameters are random in actual working conditions,which causes larger analysis errors.To solve this problem,considering the influence of random factors,a finite element analysis model of bolt pretightening failure behavior is proposed in this paper,the reliability analysis is carried out by judging whether the stress value at the thread of bolt exceeds the allowable stress value,and the reliability sensitivity analysis is calculated to evaluate the influence of various parameters on the failure phenomenon in bolt connection.The results show that the change of bolt diameter has the greatest influence on the phenomenon of bolt static strength failure,and the Poisson's ratio of material has the second influence on it.The reliability of bolt connection will increase with the increase of bolt tooth angle,screw pitch and Poisson's ratio of material,and decrease with the increase of bolt diameter,material density and elastic modulus.