我国现行压力容器规范是以弹性失效准则为基础制订的,它的特点是简便易行,但也有不足之处。例如,薄壁圆筒设计时一般只考虑薄膜应力,至于局部区域的局部应力,温差应力或压力波动引起的交变应力以及材料中因存在裂纹引起的一系列问题都不予以考虑,为了保证容器的安全运行,一般都采用较高的安全系数。实践证明,过去是可行的,也有一定的可靠性。但是,随着科学技术的发展,压力容器的尺寸越来越大,工作条件更加苛刻,不仅承受高温、高压甚至还伴随介质存有强烈腐蚀环境下工作,有时还承受疲劳和辐照脆化影响。它们除了由内压产生的薄膜应力外,还存在着边界效应引起的不连续应力,热膨胀受限引起的热应力等等。因此,如果按常规设计,不区分薄膜应力与局部应力,不考虑各种结构的局部应力大小,只是增大锅炉、压力容器承压部件安全系数或用增大容器壁厚的办法。材料在弹性范围内工作是不合理的,有时甚至起着相反的作用,厚壁容器壁厚增加会使热应力增大,材料韧性下降等。为确保压力容器在复杂苛刻条件下安全运行,充分发挥容器材料的作用,除合理选择材料,确保制造安装和检修的工艺质量及合理运行外,还有必要探索锅炉、压力容器承载时所产生的各种性质的应力及其对部件强度的影响和作用,用新的设计观点——应力分析? The current pressure vessel code in our country is based on the flexible failure criterion. It is characterized by its simplicity and convenience, but also has some shortcomings. For example, thin-walled cylinder design generally only consider the film stress, as local local stress, temperature stress or pressure fluctuations caused by alternating stress and material due to cracks caused by a series of problems are not considered, in order to ensure the safety of containers Operation, generally use a higher safety factor. Practice has proved that the past is feasible, but also a certain degree of reliability. However, with the development of science and technology, the size of pressure vessels is becoming larger and larger, and the working conditions are more harsh. Not only the high pressure and high pressure are accompanied by intense corrosion in the medium, but also the fatigue and radiation embrittlement . In addition to the film stress caused by internal pressure, they also have discontinuous stress caused by the boundary effect, thermal stress caused by limited thermal expansion, and the like. Therefore, if the conventional design does not differentiate between the film stress and the local stress, the partial stress of various structures is not considered, but the safety factor of the pressure parts of the boiler and the pressure vessel is increased or the thickness of the vessel is increased. Materials in the elastic range of work is unreasonable, and sometimes even play the opposite role, the thick wall thickness will increase the thermal stress, material toughness and so on. In order to ensure the safe operation of pressure vessels under complicated and harsh conditions and to give full play to the role of container materials, it is necessary to explore the quality of the process, manufacture, installation and maintenance of the pressure vessels, Various types of stress and its impact on the strength and role of components, with a new design point of view - stress analysis?