95连杆的可靠性研究

95连杆为95系列柴油机的重要部件,为了评价其连杆的可靠性,首先利用有限元和电测技术对连杆进行了应力和加工误差分析,确定了工作应力的均值及标准差.然后以载荷为控制因素做了该连杆的升降法疲劳实验.实验表明,连杆的疲劳强度符合威布尔分布,并求出了3个分布参数.最后利用可靠性理论讨论了连杆的破坏概率.经分析计算,95连杆的额定载荷远低于最小疲劳强度,正常情况下破坏概率为零,具有足够的疲劳强度储备,能满足柴油机提高转速和改进性能的要求,这说明利用升降法求构件的疲劳强度及其分布规律是可行的,而且是一种可靠有效的方法.

Study on Reliability of 95 Connecting Rod

The 95 connecting rod is one critical part of 95 series diesel.First of all,the stresses and the errors in machine work of the connecting rod are analyzed by finite element method and strain-gauging technique,and the mean value and standard deviation of working stress are determined.Then the staircase method fatigue testing in which load is controlling element has been made.The experiment shows that the fatigue strength of the connecting rod satisfies Weibull distribution.The three parameters of Weibull distribution are found.And finally,the failure probability of the connecting rod is studied by reliability theory.The study shows that the rated load of the connecting rod is far small in contrast with the minimum fatigue strength of the connecting rod.Under normal condition the failure probability of the connecting rod equals zero.The strength reserve of the connecting rod is sufficient for the demands of increasing the rotational speed of diesel and improving performance of diesel.Otherwise,the staircase method is an exact and efficient method to determine fatigue strength distribution of the member.