压力容器应力分类分析设计方法改进研究

发布时间：2018-01-31 03:14

本文关键词： 应力线性化应力分类法极限载荷法弹塑性应力分析法压力容器可靠性　出处：《浙江理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：压力容器应力分析设计方法于1965年率先被美国压力容器规范ASME VIII-2采用,因其先进的设计思想,可以进行详细的应力分析,解决了许多常规设计无法解决的问题,所以随后各国压力容器规范纷纷效仿美国,均在本国的设计规范中加入了应力分类法,我国亦于1995年颁布了第一部压力容器分析设计规范—JB4732。经过几十年的发展与完善,分析设计法已成为当今主流的压力容器设计方法。应力分类法是分析设计方法中的应用最为广泛,最为广大工程设计人员熟悉的一种压力容器设计方法,自W C Kroen提出应力线性化方法解决解决有限元计算的应力场与应力分类不兼容的问题后,应力分类法的应用更加广泛。然而,随着当今承压设备的复杂化和大型化发展,应力分类法在工程应用过程中暴露出一系列问题,并至今未得到很好地解决。本文针对应力分类法中存在的具体问题:(1)应力线性化理论中的某些应力分量的线性化违反了表面力边界条件和(2)应力分类法在某些应力评估区域会产生应力分类困难问题,分别作了理论研究,并给出了具体的解决方案,经过算例验证的出如下结论:针对问题(1),修改当前线性化理论,在计算薄膜加弯曲应力当量应力时,只线性化经向应力和环向应力,其余应力分量采用真实应力,新的线性化方法可以有效避免某些应力分量的线性化违反表面力边界条件问题,而且还可以避免不恰当地线性化某些应力分量导致计算结果失真的现象;针对问题(2),本文引入固体力学中的下限极限载荷理论,提出一种无需进行应力分类的基于弹性分析和下限极限载荷理论的分析设计方法,简称弹性下限法,弹性下限法有效解决了某些应力评估区域,如总体结构不连续区域的应力分类困难问题,以直接法设计结果为参照,弹性下限法相比于当前应力分类法往往给出更为合理的设计结果。另外,本文从可靠性的角度,针对当前几种压力容器设计方法,进行了系统的可靠性研究。对每一种设计方法的设计参数考虑同样的变量形式,考察每种方法的设计结果的稳定性和可靠性,研究发现:同样的变量环境下,每种方法的设计结果稳定性和可靠性各不相同,这为各种设计方法的评判和工程选用提供可一个可贵的参考。
[Abstract]:In 1965, the stress analysis design method of pressure vessel was first adopted by ASME VIII-2 of American pressure vessel code. Because of its advanced design idea, the stress analysis can be carried out in detail. Many problems that can not be solved by conventional design have been solved, so the pressure vessel codes of various countries have followed the example of the United States one after another, and have added the stress classification method to their design codes. In 1995, China also promulgated the first pressure vessel analysis design specification-JB4732. After decades of development and improvement. The analytical design method has become the mainstream design method of pressure vessel. The stress classification method is the most widely used in the analytical design method and is familiar to most engineering designers. Since the stress linearization method was proposed by W C Kroen to solve the problem of incompatibility between stress field and stress classification in finite element calculation, the stress classification method has been applied more widely. With the complication and large-scale development of pressure equipment, a series of problems have been exposed in the application of stress classification. The linearization of some stress components in stress linearization theory violates the boundary condition of surface force and the boundary condition of surface force. In some stress assessment areas, stress classification is difficult to classify. Theoretical studies are made and specific solutions are given. The results are as follows: to solve the problem, we modify the current linearization theory and calculate the equivalent stress of thin film with bending stress. Only the meridional stress and the circumferential stress are linearized, while the other stress components adopt the real stress. The new linearization method can effectively avoid the linearization of some stress components violating the boundary conditions of the surface force. It can also avoid the distortion of the calculation results caused by the improper linearization of some stress components. In order to solve the problem, this paper introduces the theory of lower limit load in solid mechanics, and puts forward an analytical design method based on elastic analysis and lower limit load theory, which does not need to be classified by stress. The elastic lower bound method, which is referred to as the elastic lower bound method, has effectively solved the problem of stress classification in some stress assessment areas, such as the discontinuous region of the total structure, which is referred to the design results of the direct method. Compared with the current stress classification method, the elastic lower bound method often gives more reasonable design results. In addition, from the point of view of reliability, this paper aims at several current design methods of pressure vessels. The design parameters of each design method are considered in the same variable form, and the stability and reliability of the design results of each method are investigated. The results show that: under the same variable environment. The stability and reliability of the design results of each method are different, which provides a valuable reference for the evaluation and engineering selection of various design methods.
【学位授予单位】：浙江理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TH49

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