Stress distribution around a single crack loaded by internal pressure [T]

1976 ◽  
Vol 11 (3) ◽  
pp. 370-372
Author(s):  
T. Yu. Kepich ◽  
V. I. Savchenko ◽  
G. V. Plyatsko ◽  
V. M. Zhirovetskii

In certain problems of plastic flow, for example, a thick tube expanded by internal pressure, it is important to consider changes in the elastic strain of material which is flowing plastically in order to deduce the correct stress distribution and deformation. The usual plastic theory which neglects elastic strains in the plastic region may lead to considerable errors in certain cases. In this paper we review the theory of the deformation of a material under combined stresses which involves both elastic and plastic components of strain. The relationship between stress and strain is represented on a plane diagram, the reduced stress-strain diagram, which facilitates discrimination between the elastic and plastic components of strain and aids considerably the solution of certain problems. The diagram can also be used to express the relationships governing the dissipation of energy during plastic flow under combined stresses. The theory is applied to the deformation of a long thick tube under internal pressure with zero longitudinal extension. The solution is compared with that based on the usual theory which neglects elastic strains in the plastic region, revealing an error which reaches a maxi­mum of over 60% in the longitudinal stress distribution. The significance of the differences between the two solutions is discussed in detail.


1995 ◽  
Vol 117 (4) ◽  
pp. 298-304 ◽  
Author(s):  
T. Sawa ◽  
R. Sasaki ◽  
M. Yoneno

This paper deals with the strength and the sealing performance of pipe flange connections combining the bonding force of adhesives with the clamping force of bolts. The epoxy adhesives or anaerobic sealants are bonded at the interface partially instead of gaskets in pipe flange connections. The stress distribution in the epoxy adhesives (anaerobic sealant), which governs the sealing performance, and the variations in axial bolt force are analyzed, using an axisymmetrical theory of elasticity, when an internal pressure is applied to a connection in which two pipe flanges are clamped together by bolts and nuts with an initial clamping force after being joined by epoxy adhesives or anaerobic sealant. In addition, a method for estimating the strength of the combination connection is demonstrated. Experiments are performed and the analytical results are consistent with the experimental results concerning the variation in axial bolt force and the strength of combination connections. It can be seen that the strength of connections increases with a decrease in the bolt pitch circle diameter. Furthermore, it is seen that the sealing performance of such combination connections in which the interface is bonded partially is improved over that of pipe flange connections with metallic gaskets.


1933 ◽  
Vol 1 (3) ◽  
pp. 87-97
Author(s):  
Gleason H. MacCullough

Abstract Analytical solutions of problems which involve creep phenomena and which are of practical interest are at present very limited in number. This paper discusses four specific problems for which solutions have been presented: namely, the problem of the flanged and bolted pipe joint under creep conditions, and the three problems of stress distribution and creep in thick-walled cylinders under internal pressure, in a beam subjected to pure bending, and in a solid circular shaft under torsion. These solutions will illustrate the kind of creep data which the designer desires the experimenter to furnish.


Author(s):  
Jinhao Huang ◽  
Chenghong Duan ◽  
Liang Wu ◽  
Xiangpeng Luo

The process, by applying an internal pressure higher than the working pressure in advance after completion of the winding to cause the liner entering the plastic stage and producing the corresponding permanent plastic deformation for the purpose of improving the carrying capacity of the vessel, is called internal pressure autofrettage. In this paper, for the high-density polyethylene liner filament winding vessels which are winded by the equivalent cooling method, the ANSYS ACP module is used to analyze the stress distribution under autofrettage condition and working condition. The influence of autofrettage pressure and cooling temperature on the stress distribution under the working conditions of the vessel is addressed. This study could provide a reference for the optimization of winding process.


1985 ◽  
Vol 107 (1) ◽  
pp. 60-63 ◽  
Author(s):  
R. Natarajan ◽  
S. Mirza

Finite element method has been used in the present work to study the stress distribution in an elbow with end constraints subjected to in-plane moment and pressure. Elbows of short radius (R/r) with varying pipe factors and bend angles have been considered. Present numerical results show for all elbow angles that follower pipe factors (thin pipes) the internal pressure reduces the flexibility factor by a larger amount than for elbows having larger pipe factors. These results are in line with the conclusions published earlier.


2013 ◽  
Vol 318 ◽  
pp. 346-349
Author(s):  
Xin Mei Yuan ◽  
Si Zhu Zhou ◽  
Tian Cheng Huang

Through the contrast analysis of optimal design of the flat and the oblique end face combination concave die which can be know the stress distribution of the combined concave die of the bicycle teeth steel bowl. It points out that the combined concave die with oblique end face can make the size on the structure of the die smaller and the structure more compact under the same internal pressure. At the same time, it provides reference to the structure optimization design of bearing partial pressure or irregular thick cylinder combination concave die.


Author(s):  
Koji Sato ◽  
Toshiyuki Sawa ◽  
Riichi Morimoto ◽  
Takashi Kobayashi

In designing of pipe flange connections with gaskets, it is important to examine the mechanical characteristics of the connections subjected to external bending moments due to earthquake such as the changes in hub stress, axial bolt forces and the contact gasket stress distribution which governs the sealing performance. One of the authors developed the PTFE blended gaskets and the authors examined the mechanical characteristics of the connections with the PTFE blended gaskets under internal pressure. However, no research was done to examine the mechanical characteristics of the connections with the newly developed PTFE blended gasket subjected to external bending moment due to earthquake. The objectives of the present study are to examine the mechanical characteristics of the connection with PTFE blended gasket subjected to external bending moment and internal pressure and to discuss the difference in the load order to the connections between the internal pressure and the external bending moments. The changes in the hub stress, the axial bolt force and the contact gasket stress distribution of the connection are analyzed using FEM. Using the obtained the gasket stress distribution and the fundamental data between the gasket stress and the leak rate for a smaller test gasket, the leak rate of the connection with the gasket is predicted under external bending moment and internal pressure. In the FEM calculations, the effects of the nominal diameter of pipe flanges on the mechanical characteristics are shown. In the experiments, ASME class 300 4 inch flange connection with 2m pipes at both sides is used and the test gasket is chosen as No.GF300 made by Nippon Valqua Industries, ltd. Four point bending moment is applied to the connection. The FEM results of the hub stress and the axial bolt forces are in a fairly good agreement with the experimental results. In addition, the FEM results of the leak rate are fairly coincided with the measured results.


2017 ◽  
Vol 64 (3) ◽  
pp. 315-326 ◽  
Author(s):  
Dominik Gunia ◽  
Tadeusz Smolnicki

Abstract This paper presents the current study of the distribution of stresses for four-point contact wire race ball bearing. The main aim of this article is to define the most important geometrical rules in a wire-race bearing. The results for bearings of different geometrical parameters are presented. In the study, one also estimates the distribution of internal pressure in particular bearing elements.


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