An estimate of the stress-strain and limiting states of composite tanks under internal pressure

1981 ◽  
Vol 17 (2) ◽  
pp. 180-183
Author(s):  
G. P. Zaitsev ◽  
V. M. Vasilevskii ◽  
A. V. Gollandtsev ◽  
N. I. Kopyl
Keyword(s):  
Internal Pressure ◽  
Stress Strain

On Thick-Walled Cylinder Under Internal Pressure

2003 ◽  
Vol 125 (3) ◽  
pp. 267-273 ◽  
Author(s):  
W. Zhao ◽  
R. Seshadri ◽  
R. N. Dubey
Keyword(s):  
Internal Pressure ◽  
Strain Curve ◽  
Stress Strain ◽  
Piecewise Linearization ◽  
Elastic Plastic ◽  
Plastic Cylinder ◽  
Parametric Functions ◽  
The Difference ◽  
New Formulation ◽  
Walled Cylinder

A technique for elastic-plastic analysis of a thick-walled elastic-plastic cylinder under internal pressure is proposed. It involves two parametric functions and piecewise linearization of the stress-strain curve. A deformation type of relationship is combined with Hooke’s law in such a way that stress-strain law has the same form in all linear segments, but each segment involves different material parameters. Elastic values are used to describe elastic part of deformation during loading and also during unloading. The technique involves the use of deformed geometry to satisfy the boundary and other relevant conditions. The value of strain energy required for deformation is found to depend on whether initial or final geometry is used to satisfy the boundary conditions. In the case of low work-hardening solid, the difference is significant and cannot be ignored. As well, it is shown that the new formulation is appropriate for elastic-plastic fracture calculations.

scholarly journals PECULIARITIES OF MODELING OF STRESS-STRAIN STATE OF PIPELINES THROUGH WHICH GAS-LIQUID MIXTURES WITH AGGRESSIVE COMPONENTS ARE TRANSPORTED

2019 ◽  
pp. 128-135
Author(s):  
A. P. Oliinyk ◽  
B. S. Nezamay ◽  
L. I. Feshanych
Keyword(s):  
Internal Pressure ◽  
Cross Sections ◽  
Strain State ◽  
Smoothing Splines ◽  
Liquid Mixtures ◽  
Equilibrium Equations ◽  
Stress Strain ◽  
Stress Strain State ◽  
Current State ◽  
The Given

The task of estimating the stress-strain state of pipelines through which gas-liquid mixtures with aggressive components are transported is considered, the purpose, object and object of research are established. The analysis of the current state of scientific and technical researches on the given subject is carried out, the circle of unresolved problems is revealed. The combined effect on the pipelines through which gas-liquid mixtures with aggressive components are transported stress – strained state change  is estimated by two models - the model for determining the change of the stress-strain state of the pipeline by data on the surface points certain set displacement   taking into account the quasi-stationarity of the process. The device uses interpolation smoothing splines and methods of differential geometry, 6 components of strain and stress tensors are determined. In order to substantiate the method of estimation of annular stresses at the wear of the pipeline walls due to the action of the aggressive components of the transported mixtures, systems of equilibrium equations for pipeline sections and for quasi-rectilinear sections with altered cross-section configuration have been derived. Boundaryt conditions for equilibrium equations are established. Calculation formulas for estimation of annular stresses arising under the action of internal pressure for sections with shape defects caused by the action of aggressive components are established. The results of calculations that allow to quantify the change of the most significant ring stresses arising in the pipeline material under the action of internal pressure in the pipeline cross sections, which were exposed to the aggressive components, are presented. It is assumed that the deformed sections are little different from the shape of the circle.

Effect of Biaxial Stress on Crack Driving Force

2006 ◽  
Author(s):  
G. Shen ◽  
W. R. Tyson
Keyword(s):  
Internal Pressure ◽  
Driving Force ◽  
Axial Stress ◽  
Axial Strain ◽  
Biaxial Stress ◽  
J Integral ◽  
Longitudinal Stress ◽  
Secondary Stress ◽  
Stress Strain ◽  
Strain Equation

A stress-strain equation of Ramberg-Osgood type is proposed to correlate the longitudinal stress with longitudinal strain of a thin plate when a constant stress is applied transversely. The same approach can be used to correlate the axial stress with axial strain for a thin-walled pipe in axial tension with internal pressure. The proposed stress-strain equation relating the longitudinal stress and strain closely approximates that of deformation theory. The effect of a secondary stress (hoop stress) on the J-integral for a circumferential crack in a pipe under axial load and internal pressure is evaluated by finite element analysis (FEA). The results show that the J-integral decreases with internal pressure at a given axial stress but increases with internal pressure at a given axial strain. It is concluded that while a secondary stress may be safely neglected in a stress-based format because it decreases the driving force at a given applied stress, it should not be neglected in a strain-based format because it significantly increases the driving force at a given applied strain.

scholarly journals The research of the stress-strain state with local thinning in pipelines and determination of allowable values of concentration stress and strain

2019 ◽  
Vol 15 (5) ◽  
pp. 384-391
Author(s):  
Dmitry A. Kuzmin ◽  
Anastasia V. Andreenkova
Keyword(s):  
Stress Concentration ◽  
Internal Pressure ◽  
Wall Thickness ◽  
Strain State ◽  
Stress Strain ◽  
Flow Acceleration ◽  
Stress Strain State ◽  
Concentration Factors ◽  
Stress Concentration Factors ◽  
Equipment And Pipelines

Relevance. The nuclear power plant contains a large number of equipment and pipelines subject to flow acceleration corrosion. As a result of a combination of various parameters - sizes (diameters, wall thickness), operational parameters (internal pressure, temperature), steels and elements types - the number of design cases is tens of thousands, without counting the possible forms of thinning. The process of maintenance and repair at the stations are doing an assessment of the accordance of actual and allowable values of wall thicknesses. The ensuring safe operations of equipment and pipelines have been introduced correction functions for regulatory functions, taking into account the forms of thinning, to determine the permissible thinning. The aim of the work. The task is to determine the influence of the forms and types of thinning on the stress-strain state and to determine the most critical thinning for straight sections of pipelines subject to flow acceleration corrosion taking into account emergency conditions. Methods. The allowable values of stress concentration factors (deformations) of pipelines subject without flow acceleration corrosion was determined taking into account allowable values, the requirements of the federal norms and rules for emergency operating conditions. For researches of the stress concentration coefficients were used the finite element method and analytical methods for various shapes, sizes and depths of thinning. Results. A method has been developed, that allows getting the maximum allowable values of stress concentration factors (deformations) for emergency operation, which afford to determine the maximum allowable depth of thinning in emergency conditions - an above criterion. The researches have been carried out definition of the stress concentration factors for local thinning with various types of these thinning. The functions of concentration coefficients depending on the geometric parameters of local thinning wall thickness were determined for a straight section of the pipeline. As a result of the research, the dependences of the sizes of thinning on the concentration coefficients for straight pipelines were created and a master-curve was obtained. The researches were carried out take into account the load from internal pressure and bending moment.

scholarly journals Formulation of the problem of finite deformations of a semi-toroidal shell under the internal pressure

2020 ◽  
pp. 155-163
Author(s):  
Виктор Вячеславович Козлов ◽  
Алексей Александрович Маркин ◽  
Вера Евгеньевна Петрова
Keyword(s):  
Internal Pressure ◽  
Strain State ◽  
Incompressible Material ◽  
Toroidal Shell ◽  
Nonlinear Ordinary Differential Equations ◽  
The Finite Element Method ◽  
Stress Strain ◽  
Stress Strain State ◽  
Nonlinear Elastic ◽  
Small Deformations

Рассматривается нелинейно-упругая осесимметричная модель полутороидальной оболочки, закрепленной по основаниям, под действием внутреннего давления. Предложен подход к формулировке мер, определяющих напряженно-деформированное состояния оболочки. Для несжимаемого материала получена замкнутая система нелинейных обыкновенных дифференциальных уравнений относительно неизвестных функций. С помощью метода конечных элементов дана оценка напряженно-деформированного состояния оболочки в случае малых деформаций. A nonlinear elastic axisymmetric model of a semi-toroidal shell fixed at the bases under the internal pressure is considered. An approach to the formulation of measures that determine the stress-strain state of the shell is proposed. For an incompressible material, a closed system of nonlinear ordinary differential equations for unknown functions is obtained. The finite element method is used to estimate the stress-strain state of the shell in the case of small deformations.

Plastic Stress-Strain Relationships—Further Experiments on the Effect of Loading History

1961 ◽  
Vol 28 (3) ◽  
pp. 439-446 ◽  
Author(s):  
J. Parker ◽  
J. Kettlewell
Keyword(s):  
Internal Pressure ◽  
Yield Surface ◽  
Yield Function ◽  
Loading History ◽  
Cross Effect ◽  
Stress Strain ◽  
Loading Paths ◽  
Degree Of Anisotropy ◽  
Alpha Brass ◽  
Plastic Stress

Further tests have been carried out on thin closed-ended tubes of alpha brass subjected to various combinations of torque and internal pressure. The effect of loading, unloading, and reloading along different paths has been investigated. The loading paths were based on a yield function which has previously been found to correlate initial radial loadings for this material, which possesses one degree of anisotropy. However, the results obtained from the second loadings suggest a cross effect which is greater than would be obtained from a nested set of yield surfaces of the foregoing form. There appears to be no evidence to support the presence of a corner in the yield surface.

Stresses in a Linear Incompressible Viscoelastic Cylinder With Moving Inner Boundary

1963 ◽  
Vol 30 (3) ◽  
pp. 335-341 ◽  
Author(s):  
M. Shinozuka
Keyword(s):  
Internal Pressure ◽  
Numerical Computation ◽  
Plane Strain ◽  
Hollow Cylinder ◽  
Digital Computer ◽  
Elastic Shell ◽  
Viscoelastic Cylinder ◽  
Stress Strain ◽  
Rate Of Increase ◽  
Inner Radius

A method is developed to find the stresses and strains in an incompressible viscoelastic hollow cylinder with moving inner radius contained by an elastic case and subject to internal pressure under the assumption of a state of plane strain. Stresses and strains are computed for a material with deviatoric stress-strain relations characteristic of a standard solid. The numerical computation is carried out with the aid of an IBM digital computer 1620 and is intended to illustrate the effects of the thickness of the cylinder, of the rate of increase of the internal pressure, and of the strength of the reinforcement provided by the elastic shell.

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