The leakage criterions of thin-wall pressure vessels,materials of missile and spacecraft

This paper presents the development of three leadage criterions to predict fracture in thin-wall pressure vessels, materials of missile and spaceraft. Experimental results show that the criterions are successful.I. Notation P internal pressure kg/mm² - _b critical stress kg/mm² - t wall thickness mm - r internal radius mm - t _o wall thickness at crack tip mm - r _o internal radius at crack tip mm - _B yield strength kg/mm² - _H circumferential stress at the yield tange of the crack tip kg/mm² - n rate of strain gardening - 2c length of surface-crack mm - a depth of surface-crack mm - L length of testing piece mm - K, C, B, aA constant     

CATASTROPHE FRACTURE OF THIN-WALL PRESSURE TUBES

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Catastrophe fracture of thin-wall pressure tubes

Catastrophe theory was used to investigate the fracture behavior of thin-wall cylindrical tubes subjected to internal explosive pressure. Based on the energy theory and catastrophe theory, a cusp catastrophe model for the fracture was established, and a critical condition associated with the model is given. Contributed by YANG Gui-tong Biographies: WEI De-min (1955-); YANG Gui-tong (1931-)     

Experimental study of separation-zone pressure pulsation

We examine extremely nonuniform separated water flow in the initial segment of a penstock of rectangular section resulting from the separated flow past a two-dimensional gate. The meansquare deviations p', one-dimensional frequency spectra S(), spatial correlations r(x), and distribution functions F(p) of the pressure pulsation are determined experimentally at points of the solid stationary boundary above the roll zone for significantly different absolute pressures in the stream. Changes in the structure of the hydrodynamic action on the boundary resulting from phase transformations in the fluid—the appearance of air and air-vapor inclusions—are noted. The measurement data are compared with the results of theoretical calculations.The author wishes to thank V. M. Lyatkher for his interest in this study and helpful advice.     

Design-stress basis for pressure vessels

The modes of failure of a pressure vessel which are affected by the choice of material and wall thick-ness are given. The factors which should be considered in the choice of an allowable stress low enough to prevent these failure modes are discussed. 1970 Murray Lecture was presented at 1970 SESA Fall Meeting held in Boston, Mass., on October 18–22.     

Perfectly plastic momentless pressure vessels

International Applied Mechanics -     

带平板封头的双层爆炸容器动力响应的实验研究

对采用平封头的圆柱形双层爆炸容器在内部装药爆炸所产生的载荷作用下的动力响应进行了实验研究。研究了容器内部抽真空和内层容器结构形式等因素对爆炸容器弹塑性响应的影响,探讨了平封头应用的可行性。     

Kinematics of fragments from disintegrating pressure vessels

The disintegration of an elastoplastic vessel filled with high-pressure gas is experimentally investigated and a model of the process is proposed.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 6, pp. 88–93, November–December, 1988.     

Stresses at nozzle connections of pressure vessels

The presence of a nozzle in a pressure vessel creates a region of increased localized stress in the vicinity of the opening. The purpose of this study is to provide experimental data which show the general state of stress at nozzle openings. This paper is a report of the techniques and methods used in analyzing three insert-type nozzles when loaded by internal pressure.     

Fracture analysis of thick-wall cylinder pressure vessels

Fracture mechanics analysis of cylindrical pressure vessels is described in a brief fracture case study. Also included are additional examples of crack growth in pressure vessels and cannons. The case study is of an early brittle failure and subsequent redesign of a cannon tube. Fracture mechanics test methods are described which were developed specifically for testing of cylindrical geometries. Three examples of current fracture analysis of cylindrical pressure vessels are presented. Fast fracture of a vessel is described, including effects of tension residual stress and crack shape. Evidence of environmentally assisted fracture of a cannon tube is presented. Fatigue crack growth and life calculation methods for cylindrical pressure vessels are discussed including effects of compressive residual stress due to overstrain.     

Experimental and numerical study of pressure wave refrigerator performance

A new compact pressure wave refrigerator has been designed and manufactured at the Shock Wave Research Center, Institute of Fluid Science, Tohoku University. The performance of this device was investigated for combinations of major operational parameters, such as the rotational speed of gas distributor, the length of expansion tubes, the input gas pressure. The maximum temperature decrease of 20 K has been measured. Some theoretical consideration to the efficiency of the pressure wave refrigerator and two-dimensional numerical simulations were carried out in order to understand the wave interactions that take place inside the device.Received: 26 May 2003, Accepted: 12 August 2003, Published online: 14 October 2003 Correspondence to: T. Saito     

Producing epoxy-model pressure vessels for fracture tests

A convenient and economical technique for producing large numbers of flaw-free, well-finished, epoxy-model pressure vessels is described. The novel feature of the technique is the dependence on all-metal cores. Also of interest is the low turn-around time per mold.     

Radial vibrations of axisymmetrically loaded stepped pressure vessels

IntroductionUsedextensivelyinengineeringarethin-walledpressurevessels,suchasboilersinpowerplants,rotordrumsOfturbines,leadersofcylinders,andgasstoragetanks.Inthispaper,discussedareradialvibrationsofaxisymmetricallyloadedcylindricalpressurevesselswiththicknessvaried.1FreeVibration1.1DifferentialequationforfreevibrationanditsgeneralsolutionAssumethereisathin-walledPressurevesselwithtotallength1andthicknessvariedinnstepsalongaams.Foreachstep,lengthh=xi--xi--11massperunitareaml,thicknessh.,ac?fi…     

Fracture-arrest capabilities of annularly reinforced cylindrical pressure vessels

The elastic-energy-release rate is experimentally determined in plastic models of annularly reinforced type cylindrical pressure vessels. The feasibility of effecting crack arest is demonstrated and the prediction of the arrested crack length is schematically indicated.     

纤维缠绕复合材料压力容器渐进损伤分析

利用大型有限元软件ANSYS的参数化设计语言(APDL)建立了纤维缠绕复合材料压力容器的有限元模型,该模型真实地反应了复合材料压力容器封头处纤维缠绕层的厚度以及纤维缠绕角度沿子午线不断变化的情况,即充分体现该压力容器结构的真实性.针对建立的有限元模型,对复合材料压力容器在一定内压下的应变进行了分析,将分析的结果与试验结果比较,验证该模型的准确性.在此基础上进行了复合材料压力容器的渐进损伤分析,获得了复合材料压力容器在外载荷逐渐增加的情况下,复合材料缠绕层逐层失效破坏的详细信息,为复合材料压力容器的设计提供一定的依据.     

承压薄壁容器应力分析的讨论

通过讲述与引伸承压薄壁圆筒的应力分析, 引导学生关联几种承力构件 的受力特征, 并展示其在日常生活中的应用实例, 可作为该部分课堂教学的补充材料.     

Experimental study on the two-phase pressure drop in copper foams

Experiments were performed to study pressure drops in copper foams embedded in a rectangular copper channel. De-ionized water was used as the working fluid with mass fluxes of 30–200 kg/m² s, and inlet temperature of 40–80°C. The copper foam has the porosity of 0.88 and the pore densities of 30, 60 and 90 ppi (pores per inch). Both single-phase liquid flow and boiling two-phase flow are studied. Effects of mass fluxes, vapor mass qualities, and average pore diameters of metallic foams are investigated. It is found that friction factors for the single-phase liquid flow are mainly dependent on the Reynolds number and the average pore diameter of metallic foams. The friction factors are decreased with increases in the Reynolds numbers, and will approach 0.22 at high Reynolds numbers. For the boiling two-phase flow, two-phase pressure drops are increased with increases in the outlet vapor mass qualities, mass fluxes, and ppi values. The two-phase multiplier is increased with increases in the outlet vapor mass qualities and mass fluxes, and it is decreased with increases in the Martinelli parameter and will attain a constant value depending on the mass fluxes. The larger the mass fluxes, the larger the constant value is. An experimental correlation considering the effects of vapor mass qualities, mass fluxes, and average pore diameters of metallic foams is recommended, showing good accuracy to predict the two-phase pressure drops in metallic foams.