低温低应力工况压力容器的设计

对低温低应力工况下的压力容器材料的应力状况及容器的工作状况进行了分析、论述,阐述了设计中应注意的问题及相应的解决方法,为低温压力容器的设计提供了有益的参考。     

压力容器的可靠性分析

利用可靠性分析方法,对压力容器的可靠度进行了研究,并给出计算实例     

Radial breathing mode of carbon nanotubes subjected to axial pressure

In this paper, a theoretical analysis of the radial breathing mode (RBM) of carbon nanotubes (CNTs) subjected to axial pressure is presented based on an elastic continuum model. Single-walled carbon nanotubes (SWCNTs) are described as an individual elastic shell and double-walled carbon nanotubes (DWCNTs) are considered to be two shells coupled through the van der Waals force. The effects of axial pressure, wave numbers and nanotube diameter on the RBM frequency are investigated in detail. The validity of these theoretical results is confirmed through the comparison of the experiment, calculation and simulation. Our results show that the RBM frequency is linearly dependent on the axial pressure and is affected by the wave numbers. We concluded that RBM frequency can be used to characterize the axial pressure acting on both ends of a CNT.     

The application of fracture mechanics to prestressed concrete pressure vessels

A fracture mechanics approach has been used to predict the approximate extent of cracking in a prestressed concrete pressure vessel subject to overpressure. The stress intensity factor has been calculated by means of the crack closure work concept and finite element stress analysis for a range of crack lengths. By comparing these results with published pseudo fracture toughness data for concrete the extent of cracking has been predicted.     

A two-dimensional stress analysis of single-lap adhesive joints subjected to external bending moments

The stress distributions in single-lap adhesive joints of similar adherends subjected to external bending moments have been analyzed as a three-body contact problem using a two-dimensional theory of elasticity (plain strain state). In the analysis, both adherends and the adhesive were replaced by finite strips. In the numerical calculations, the effects of the ratio of Young's moduli of the adherends to that of the adhesive and the adhesive thickness on the stress distribution at the interfaces were examined. It was found that the stress singularity occurs at the edges of the interfaces and that the peel stress at the edges of the interfaces increases with decreasing Young's modulus of the adherends. It was noticed that the singular stress decreases at the edges of the interfaces as the adherend thickness increases. In addition, photoelastic experiments and FEM (finite element method) calculations were carried out and fairly good agreement was found between the analytical and the experimental results.     

Discrimination of failure criteria with ceramic rings subjected to internal pressure

An experimental procedure for gathering short-time strength data and to discriminate multiaxial failure criteria of ceramics is presented. It uses concentric rings of different diameter ratios which are subjected to internal pressure and allows specimen to have “as-fired”-surfaces. Due to mainly tensional stresses, crack-face friction effects in the material have minor influence on the discrimination of failure criteria. Test series with alumina have been executed and the results are presented.     

含缺陷压力容器失效概率分析方法初步研究

基于双判据准则，考虑容器承受载荷、材料断裂韧性及流变应力等参数随机特性，建立了含缺陷压力容器失效极限状态方程，应用解析方法和数值方法，对含缺陷受内压容器失效概率进行了分析计算。结果表明，两种分析方法具有较好的一致性     

Lifetime prediction for ABS pipes subjected to combined pressure and deflection loading

As part of an investigation into the performance of acrylonitrile‐butadiene‐styrene (ABS) systems for water transportation, this paper presents a method for predicting the service lifetimes of buried pipes under in‐service loading conditions. A linear fracture mechanics approach was used to analyze brittle failure initiating from adventitious flaws located at the bore surface of pipe. Failure criteria were determined using the time‐dependent, quasistatic, plane strain fracture toughness of the ABS material, combined with empirical parameters that describe slow, steady crack growth. The expected operating conditions of a buried pipe were then separated into static loading contributions from internal pressure, diametrical deflection and residual stress. Idealized stress intensity factors associated with mode‐I crack opening under each of these components were determined using a finite element analysis and superposed to describe the general case in service. The computed nett stress intensity factor was then combined with the previously determined fracture toughness and slow crack growth data in an algorithm to simulate incremental radial crack growth from the pipe bore. Predicted failure times compared well with an experimental model of expected operating conditions, which combined hydrostatic pressure and parallel‐plate deflection loading of an internally notched pipe. The prediction method was also used to identify the factors that control the lifetime of a pipe in service. The influence of material visco‐elasticity was investigated by simulating variations in fracture toughness and slow crack growth resistance. It was proposed that, in practice, these variations are governed by opposing changes in visco‐elasticity. The effect of changing diametrical deflection and residual stress distribution were also simulated, allowing recommendations on pipe manufacture and installation conditions to be made.     

A study of composite foams for diving suits subjected to high hydrostatic pressure

In order to obtain foams possessing flexibility and at the same time heat insulation under high hydrostatic pressure, composite foams with spherical rigid foams filled in flexible rubber foam at certain intervals were prepared and their thermal conductivity and flexural rigidity were studied. The following points were found: (1) With a unit model having a spherical rigid foam in the middle, the thermal conduction of a composite foam was analyzed under the conditions of steady one-dimensional heat flow. Theoretical equations giving overall coefficients of heat transmission under atmospheric and hydrostatic pressures were obtained, and the adequacy of these theoretical equations was confirmed by the measurement of overall coefficients of heat transmission of composite foams in an apparatus so constructed as to allow heat conduction experiments under pressures ranging from atmospheric to the hydrostatic pressure corresponding to 100-m depth in water. (2) The effect of the filled spherical rigid foams on heat insulation is notable under hydrostatic pressures corresponding to a 20-m depth or more in water. Under the hydrostatic pressure corresponding to a 100-m depth in water, the coefficient of heat insulation of the most closely filled composite foam used in the experiment was approximately 35% larger than that of the unfilled foam, while the theoretical most closely filled composite foam gives an approximately 110% increase. (3) Under the hydrostatic pressure corresponding to a 100-m depth in water, the flexural rigidity of the most closely filled composite foam used in the experiment was approximately one half that of an unfilled foam of the same heat insulating property.     

浅谈压力容器的疲劳分析设计

随着工业的迅速发展,压力容器承受循环载荷的情况日益增多,产生疲劳失效事故的可能性也在增加,压力容器的疲劳分析设计越来越引起了人们的关注和重视.笔者以D一06A/B干燥器为实例,简要叙述了压力容器疲劳分析设计中的载荷和结构分析、应力计算、交变应力强度幅的求取、设计疲劳曲线的应用、疲劳强度校核等主要步骤及实施要点和注意事项.     

压力容器设计中焊接接头系数(φ)值的选取

对压力容器 设计中几处焊接接头系数φ值的选取,论述了自己的观点。     

Buckling of composite cylinders under external pressure

Experimental results from buckling tests on thin shell structures made of filament-wound glass fiber reinforced plastic are compared to values calculated with three different procedures. These procedures are: (1) a linear stability analysis for anisotropic, heterogeneous, thin, cylindrical shells, (2) a proposed design code, and (3) a national standard. Imperfection surveys in the circumferential direction were conducted and were found to be much larger than imperfections typical for metallic thin shells. All three procedures yield design pressures lower than observed buckling pressures. The analytical method and the standard are less conservative than the proposed design code and may possibly permit the fabrication of safe and more economical structures.     

基于信息熵的扁平绕带式容器试验压力

基于信息熵中模糊性度量与随机性度量相等可实现模糊变量等效为随机变量的原理,把扁平绕带容器的模糊静强度和模糊载荷等效为随机静强度和随机载荷,从控制扁平绕带容器模糊静强度在正常操作与压力试验时可靠度的角度,对其安全系数、试验压力系数与超压限制系数进行了探索。研究表明：（1）模糊屈服强度可靠度在正常操作时应不低于0．99744,在气压与液压试验时应分别不低于0．98300与0．95053;模糊爆破强度可靠度在正常操作时应不低于0．99999999535,在气压与液压试验时应分别不低于0．9999999519与0．999999772。（2）屈服安全系数应不小于1．50,抗拉安全系数应不小于2．70。（3）试验压力系数在气压试验时应不小于1．05但不大于1．16,在液压试验时应不小于1．05但不大于1．25。（4）在气压与液压试验时,超压限制系数在屈服失效准则下应分别不大于0．7766与0．8361,在爆破失效准则下应分别不大于0．4310与0．4449。     

浅述PED技术要求在压力容器设计中的应用

在出口压力容器设备的设计中,经常需要应用<承压设备指令>(Pressure EquipmentDirective简称PED)进行设计认证.就设计的出口压力容器中贯彻PED的一些技术要求及与我国压力容器的设计标准如GB150等存在的一些异同作一比较.     

压力容器圆筒体上大开孔补强问题的探讨

容器上开孔后,必须充分考虑开孔补强问题.本文介绍了等面积法和压力面积法两种开孔补强方法关于开孔补强的异同,并就其中的一些问题进行了探讨.     

压力容器的安全与结构设计

根据过去的压力容器破坏事故分析,有相当一部分是由于结构设计不合理引起的,认为设计合理可靠的结构和强度设计同样重要。就压力容器结构设计的一般原则和结构设计常遇到的问题,如壳体接管开孔、开孔补强和焊接结构的设计实例予以阐述。     

有初始几何缺陷的压力容器非线性分析

本文在以应力应变表示的内时本构方程的基础上，采用对以内蕴时间表示的本构方程进行厚度积分的方法，导出了以薄壳中面广义应力及广义应变表示的几时本构方程。应用这一本构模型对具有初始几何缺陷的压力容器进行了弹塑性大变形计算分析。结果表明本文的方法经济有效、实用性强，对于压力容器设计分析可提供有价值的理论依据。