一、前言近年来,机械系统向着大型化、复杂化方向发展,其功能也日益趋于完善和提高。对某些机械系统的设计,可靠性的问题逐渐显出其重要性,并即将居于首要地位。在机械系统的设计过程中,普遍要遵守一个最基本的设计准则,那就是要满足机械的强 I. Introduction In recent years, the mechanical system has been developed in a direction of becoming larger and more complex, and its functions have also been increasingly refined and improved. The design and reliability issues of some mechanical systems have gradually become more and more important and will soon be at the top of the list. In the mechanical system design process, generally to comply with one of the most basic design criteria, that is, to meet the mechanical strength