Strength of Thick-Walled Pressure Vessels for Materials With Directional Properties

1962 ◽  
Vol 84 (2) ◽  
pp. 197-202
Author(s):  
A. E. Dapprich ◽  
Joseph Marin ◽  
Tu-Lung Weng
Keyword(s):  
Tensile Stress ◽  
Pressure Vessel ◽  
Anisotropic Material ◽  
Pressure Vessels ◽  
Maximum Pressure ◽  
Closed Solution ◽  
Strain Relation ◽  
Stress Strain Relation ◽  
Cylindrical Pressure Vessel

This paper develops a theory for the determination of the plastic pressure-deformation relation in a thick-walled cylindrical pressure vessel subjected to internal pressure and made of an anisotropic material. In this theory, large or finite strains are considered and a closed solution is found for the pressure-strain relation based on a modified log-log tensile stress-strain relation. Theory is also developed for predicting the maximum pressure which the vessel can withstand.

scholarly journals Methods for Structural Stress Determination according to EN 13445-3 Annex NA – Comparison with other Codes for Unfired Pressure Vessels

2018 ◽  
Vol 165 ◽  
pp. 10003
Author(s):  
Ralf Trieglaff ◽  
Jürgen Rudolph ◽  
Martin Beckert ◽  
Daniel Friers
Keyword(s):  
Pressure Vessel ◽  
Pressure Vessels ◽  
Structural Stress ◽  
Stress Determination ◽  
User Friendliness ◽  
Fatigue Assessment ◽  
Shell Elements ◽  
European Working ◽  
The Status

The European Pressure Vessel Standard EN 13445 provides in its part 3 (Design) a simplified method (Clause 17) and a detailed method for fatigue assessment (Clause 18). Clause 18 “Detailed Assessment of Fatigue Life” is under revision within the framework of the European working group CEN/TC 54/WG 53 – Design methods with the aim of reaching a significant increase in user-friendliness and a clear guideline for the application. This paper is focused on the new informative annex NA ”Instructions for structural stress oriented finite elements analyses using brick and shell elements”. As an essential amendment for the practical user, the determination of structural stress ranges for fatigue assessment of welds is further specified in this new annex. Different application methods for the determination of structural stresses are explained in connection with the requirements for finite element models and analyses. This paper will give a short overview of the proposed approaches of structural stress determination in annex NA of the revised EN 13445-3. It will present the status of the approaches based on the results of fatigue analyses according to EN 13445-3 Clause 18 for different application examples. For verification purposes, the results of the approaches proposed in EN 13445-3 are compared with the results of other pressure vessel design codes for nuclear and non-nuclear application.

Investigating the in-plane mechanical behavior of single-ply quasi-unidirectional glass fiber/polypropylene composites

2017 ◽  
Vol 37 (4) ◽  
pp. 401-409 ◽  
Author(s):  
Zhanyu Zhai ◽  
Christian Gröschel ◽  
Dietmar Drummer
Keyword(s):  
Tensile Stress ◽  
Glass Fiber ◽  
Tensile Tests ◽  
Stress Strain ◽  
Polypropylene Composites ◽  
Strain Relation ◽  
Stress Strain Relation ◽  
Pp Composites ◽  
Experimental Values ◽  
First Time

Abstract The objective of this study was to determine the engineering constants and off-axis tensile stress-strain relation of single-ply quasi-unidirectional (UD) glass fiber (GF)/polypropylene (PP) composites using the new approach. A series of off-axis tensile tests of quasi-UD composites were carried out. In this study, Puck’s interfiber fracture criterion was expanded for the first time to estimate the off-axis tensile stresses of UD composites. With the experimental values, the shear properties were obtained through the curve-fitting methods. Damage mechanisms were demonstrated to evolve with the loading angle. By comparison to experimental data, the Hahn-Tsai equation, together with the transformation equation, was found to be adequate to describe the off-axis tensile stress-strain relation of single-ply quasi-UD GF/PP composites.

An Improved Method of Determining the Disturbed State Concept Model Parameters

2014 ◽  
Vol 919-921 ◽  
pp. 1345-1349
Author(s):  
Wei Lu ◽  
Jia Jun Pan
Keyword(s):  
Triaxial Compression ◽  
Model Parameters ◽  
Improved Method ◽  
Stress Strain ◽  
Material Parameters ◽  
Concept Model ◽  
Strain Relation ◽  
Stress Strain Relation ◽  
Disturbed State Concept

The method of postulate of relatively intact model in the disturbed concept model is reached. Because it is more difficult to assume relatively intact curve by observed experimental data, a method which could automatically calculate the stress strain relation curve of relative intact by triaxial compression test data is raised, so that the determination of material parameters becomes easier, and the improved method is verified by numerical calculation. The results show that this method can effectively determine the stress strain relation curve of relative intact.

In Vivo Determination of the Stress-Strain Relation of the Human Myometrium

1976 ◽  
Vol 55 (4) ◽  
pp. 325-331 ◽  
Author(s):  
Ingemar Joelsson ◽  
Lennart Gidlund ◽  
Bo Anzén ◽  
Axel Ingelman-Sundberg
Keyword(s):  
Human Myometrium ◽  
Stress Strain ◽  
Strain Relation ◽  
Stress Strain Relation

Effect of Material Properties on the Strain to Failure of Thick-Walled Cylinders Subjected to Internal Pressure

1994 ◽  
Vol 116 (2) ◽  
pp. 96-104 ◽  
Author(s):  
D. P. Roach ◽  
T. G. Priddy
Keyword(s):  
Internal Pressure ◽  
Material Properties ◽  
Maximum Pressure ◽  
Plastic Response ◽  
Empirical Formulas ◽  
Stress Strain Relation ◽  
Simple Tension ◽  
Bursting Pressures ◽  
Versus Strain

The determination of the fully plastic response and pressure limit of a pressure vessel is of considerable importance in design, especially in autofrettage considerations. This paper presents the results of an experimental study which measured the maximum internal pressure which can be applied to thick-walled cylindrical vessels. Both aluminum and steel, with material properties ranging from ductile to brittle, were tested at stress levels through plastic and strain hardening ranges to fracture. From these tests, the pressure-expansion and through-thickness yielding characteristics were determined for these specimens. It is shown that a strain-to-failure criterion, based on the triaxiality of stress in the critical region, can be used to predict the complete pressure versus strain relations and maximum pressure for these cylinders. A simple tension-true stress-strain relation of the material is employed to analytically predict the response of the cylinder into the plastic regime. Finally, simplified theoretical and empirical formulas for bursting pressures are checked against the experimental results.

Thermomechanical Creep Analysis of FGM Thick Cylindrical Pressure Vessels with Variable Thickness

2018 ◽  
Vol 10 (01) ◽  
pp. 1850008 ◽  
Author(s):  
Mosayeb Davoudi Kashkoli ◽  
Khosro Naderan Tahan ◽  
Mohammad Zamani Nejad
Keyword(s):  
Temperature Gradient ◽  
Differential Equations ◽  
Variable Thickness ◽  
Pressure Vessel ◽  
Shear Deformation Theory ◽  
Pressure Vessels ◽  
Mechanical And Thermal Properties ◽  
Creep Response ◽  
Cylindrical Pressure Vessel ◽  
Creep Analysis

In the present study, a theoretical solution for thermomechanical creep analysis of functionally graded (FG) thick cylindrical pressure vessel with variable thickness based on the first-order shear deformation theory (FSDT) and multilayer method (MLM) is presented. To the best of the researchers’ knowledge, in the literature, there is no study carried out into FSDT and MLM for creep response of cylindrical pressure vessels with variable thickness under thermal and mechanical loadings. The vessel is subjected to a temperature gradient and nonuniform internal pressure. All mechanical and thermal properties except Poisson’s ratio are assumed to vary along the thickness direction based on a power-law function. The thermomechanical creep response of the material is described by Norton’s law. The virtual work principle is applied to extract the nonhomogeneous differential equations system with variable coefficients. Using the MLM, this differential equations system is converted into a system of differential equations with constant coefficients. These set of differential equations are solved analytically by applying boundary and continuity conditions between the layers. In order to verify the results of this study, the finite element method (FEM) has been used and according to the results, good agreement has been achieved. It can be concluded that the temperature gradient has significant influence on the creep responses of FG thick cylindrical pressure vessel.

Verifying Structural Integrity of Repaired Cylindrical Pressure Vessels by Partitioning Method

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
Husain J. Al-Gahtani ◽  
Mahmoud Naffa'a
Keyword(s):  
Pressure Vessel ◽  
Structural Integrity ◽  
Welded Joint ◽  
Test Validity ◽  
Pressure Vessels ◽  
Testing Method ◽  
State Of Stress ◽  
Cylindrical Pressure Vessel ◽  
Pressure Test ◽  
Alternative Test

Pressure vessels that undergo repairs are normally pressure tested to verify their structural integrity before returning into service. Conventionally, the entire vessel is pressure tested, according to the relevant construction code. In this paper, partitioning the pressure vessel is suggested as an equivalent alternative test arrangement, where pressure testing is limited to the zone where a repair has been performed. Use of such an arrangement would alleviate potential concerns associated with the conventional testing method. Procedures are provided to specify the position of the partition relative to the repair location, in order to maintain the state-of-stress to that achieved in a conventional pressure test. Validity of this approach has been demonstrated for a repaired full-circumferential welded joint in the wall of a cylindrical pressure vessel.

On the Determination of the Influence of an Axial Preload Owing to Bolting on a Cylindrical Pressure Vessel

1961 ◽  
Vol 83 (2) ◽  
pp. 215-218
Author(s):  
P. R. Paslay
Keyword(s):  
Numerical Integration ◽  
Plastic Flow ◽  
Pressure Vessel ◽  
Elastic Solution ◽  
Cylindrical Pressure Vessel

An idealization of a cylindrical pressure vessel with end plates fastened by longitudinal bolts is considered. The initial axial preload is restricted to be below the load necessary to begin plastic flow and the bolting is assumed elastic throughout the application of pressure. The elastic solution is obtained and the plastic solution may be found by a numerical integration. An illustrative problem is included.

Post Autofrettage Thermal Treatment and Its Effect on Re-Yielding of High Strength Pressure Vessel Steels

2009 ◽  
Author(s):  
E. Troiano ◽  
J. H. Underwood ◽  
A. P. Parker ◽  
C. Mossey
Keyword(s):  
Thermal Treatment ◽  
Low Temperature ◽  
Plastic Strain ◽  
Residual Stresses ◽  
Pressure Vessel ◽  
Pressure Vessels ◽  
Lower Amount ◽  
Isotropic Hardening ◽  
Maximum Pressure ◽  
Compressive Residual Stresses

The autofrettage process of a thick walled pressure vessel involves applying tensile plastic strain at the bore of the vessel which reverses during unloading and results in favorable compressive residual stresses at the bore and prolongs the fatigue life of the component. In thick walled pressure vessels this process can be accomplished with either a hydraulic or mechanical overloading process. The Bauschinger effect, which is observed in many of the materials used in thick walled pressure vessels, is a phenomenon which results in lower compressive residual stresses than those predicted with classic ideal isotropic hardening. The phenomenon is a strong function of the amount of prior tensile plastic strain. A novel idea which involves a multiple autofrettage process has been proposed by the present authors. This process requires a low temperature post autofrettage thermal treatment which effectively returns the material to its original yield conditions without affecting its residual stress state. Details of this low temperature thermal treatment are proprietary. A subsequent second autofrettage process generates a significantly lower amount of plastic strain during the tensile re-loading and results in higher compressive residual stresses. This paper reports the details of exploratory tests involving tensile and compressive loading of a test coupon, followed by a low temperature post plastic straining thermal treatment, and subsequent re-loading in tension and compression. Finally results of a full scale Safe Maximum Pressure (SMP) test of pressure vessels are presented; these tests indicate a significant increase (11%) in SMP.

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