Study on the Structural Safety Evaluation for Pressure Vessel of the CNG Vehicle Using F.E.M.

2012 ◽  
Vol 569 ◽  
pp. 598-602 ◽  
Author(s):  
Eui Soo Kim ◽  
Jong Hyuk Kim ◽  
Byung Sun Moon ◽  
Jae Mo Goh
Keyword(s):  
Pressure Vessel ◽  
Storage Tank ◽  
Safety Management ◽  
Yield Criterion ◽  
Safety Evaluation ◽  
Pressure Vessels ◽  
Structural Safety ◽  
Test Procedures ◽  
Design Variables ◽  
Von Mises

CNG vehicles have to be equipped with a safe and reliable storage tank, such as composite pressure vessels, since the failure of the CNG storage tank induces fatal damages to passengers. In this research, the cause of vessel facture is investigated through formal inspection and engineering test procedures. Specifically, the composite pressure vessel design will be validated using the finite element method. In order to validate values of the optimal design variables in accordance with standard of the high pressure gas safety management, we used safety probability such as Von-Mises yield criterion, Tsai-Hill theory and stress ratio.

Stress Field Around a Large Opening in a Pressure Vessel During a Major Repair

2009 ◽  
Author(s):  
Erik Garrido ◽  
Euro Casanova
Keyword(s):  
Pressure Vessel ◽  
New Technologies ◽  
Mechanical Design ◽  
General Purpose ◽  
Pressure Vessels ◽  
Mechanical Equipment ◽  
Stress Distributions ◽  
Large Opening ◽  
Von Mises ◽  
Case Basis

It is a regular practice in the oil industry to modify mechanical equipment to incorporate new technologies and to optimize production. In the case of pressure vessels, it is occasionally required to cut large openings in their walls in order to have access to the interior part of the equipment for executing modifications. This cutting process produces temporary loads, which were obviously not considered in the original mechanical design. Up to now, there is not a general purpose specification for approaching the assessments of stress levels once a large opening in a vertical pressure vessel has been made. Therefore stress distributions around large openings are analyzed on a case-by-case basis without a reference scheme. This work studies the distribution of the von Mises equivalent stresses around a large opening in FCC Regenerators during internal cyclone replacement, which is a frequently required practice for this kind of equipment. A finite element parametric model was developed in ANSYS, and both numerical results and illustrating figures are presented.

Strength Criteria Versus Plastic Flow Criteria Used in Pressure Vessel Design and Analysis1

2016 ◽  
Vol 138 (4) ◽  
Author(s):  
Xian-Kui Zhu
Keyword(s):  
Plastic Flow ◽  
Pressure Vessel ◽  
Yield Criterion ◽  
Pressure Vessels ◽  
Burst Pressure ◽  
Thin Wall ◽  
Strength Criteria ◽  
Integrity Assessment ◽  
Ductile Materials ◽  
Strength Design Criteria

This paper presents a critical comparison of the traditional strength criteria and the modern plastic flow criteria used in the structural design and integrity assessment of pressure vessels. This includes (1) a brief review of the traditional strength criteria used in the ASME Boiler and Pressure Vessel (B&PV) Code, (2) a discussion of the shortcomings of the traditional strength criteria when used to predict the burst pressure of pressure vessels, (3) an analysis of challenges, technical gaps, and basic needs to improve the traditional strength criteria, (4) a comparison of strength theories and plasticity theories for ductile materials, (5) an evaluation of available plastic flow criteria and their drawbacks in prediction of burst pressure of pressure vessels, (6) a description of a newly developed multiaxial yield criterion and its application to pressure vessels, and (7) a demonstration of experimental validation of the new plastic flow criterion when used to predict the burst pressure of thin-wall pressure vessels. Finally, recommendations are made for further study to improve the traditional strength design criteria and to facilitate utilization of the modern plastic flow criteria for pressure vessel design and analysis.

Stress Concentration and Stress Intensity for Pressurized Eroded Autofrettaged Thick Cylinders With Bauschinger Effect

2010 ◽  
Author(s):  
Q. Ma ◽  
C. Levy ◽  
M. Perl
Keyword(s):  
Stress Intensity ◽  
Stress Concentration ◽  
Bauschinger Effect ◽  
Thermal Loading ◽  
Yield Criterion ◽  
Pressure Vessels ◽  
Short Cracks ◽  
Finite Element Package ◽  
Von Mises ◽  
Walled Cylinder

Our previous studies have shown that stress intensity factors (SIFs) are influenced considerably from the presence of the Bauschinger Effect (BE) in thick-walled pressurized cracked cylinders. For some types of pressure vessels, such as gun barrels, working in corrosive environment, in addition to acute temperature gradients and repetitive high-pressure impulses, erosions can be practically induced. Those erosions cause stress concentration at the bore, where cracks can readily initiate and propagate. In this study, The BE on the SIFs will be investigated for a crack emanating from an erosion’s deepest point in a multiply eroded autofrettaged, pressurized thick-walled cylinder. A commercial finite element package, ANSYS, was employed to perform this type of analysis. A two-dimensional model, analogous to the authors’ previous studies, has been adopted for this new investigation. Autofrettage with and without BE, based on von Mises yield criterion, is simulated by thermal loading and the SIFs are determined by the nodal displacement method. The SIFs are evaluated for a variety of relative crack lengths, a0/t = 0.01–0.45 emanating from the tip of the erosion of different geometries including (a) semi-circular erosions of relative depths of 1–10 percent of the cylinder’s wall thickness, t; (b) arc erosions for several dimensionless radii of curvature, r′/t = 0.05–0.4; and (c) semi-elliptical erosions with ellipticities of d/h = 0.5–1.5, and erosion span angle, α, from 6 deg to 360 deg. The effective SIFs for relatively short cracks are found to be increased by the presence of the erosion and further increased due to the BE, which may result in a significant decrease in the vessel’s fatigue life. Deep cracks are found to be almost unaffected by the erosion, but are considerably affected by BE.

Yield Pressure Measurements and Analysis for Autofrettaged Cannons

2002 ◽  
Author(s):  
John H. Underwood ◽  
David B. Moak ◽  
Michael A. Audino ◽  
Anthony P. Parker
Keyword(s):  
Residual Stress ◽  
Yield Strength ◽  
Yield Criterion ◽  
Axial Stress ◽  
Design Procedure ◽  
Pressure Vessels ◽  
Pressure Measurements ◽  
Strain Rate Effects ◽  
Axial Residual Stress ◽  
Von Mises

Yield pressure corresponding to a small permanent OD strain was measured in quasi-static laboratory tests of autofrettaged ASTM A723 steel cannon pressure vessels. Yield pressure was found to be a consistent ratio of the yield strength measured from specimens located in close proximity to the area of observed yielding. Yield pressure measurements for dynamic cannon firing with typically a 5 ms pressure pulse duration gave 14% higher yield pressures, attributed to strain rate effects on plastic deformation. Calculated Von Mises yield pressure for the laboratory test conditions, including the Bauschinger-modified ID residual stress and open-end vessel conditions, agreed with measured yield pressure within 3–5%. Calculated yield pressure was found to be insensitive to the value of axial residual stress, since axial stress is the intermediate value in the Von Mises yield criterion. A description of yield pressure normalized by yield strength was given for autofrettaged A723 open-end pressure vessels over a range of wall ratio and degree of autofrettage, including effects of Bauschinger-modified residual stress. This description of yield pressure is proposed as a design procedure for cannons and other pressure vessels.

Yield Pressure Measurements and Analysis for Autofrettaged Cannons

2003 ◽  
Vol 125 (1) ◽  
pp. 7-10 ◽  
Author(s):  
John H. Underwood ◽  
David B. Moak ◽  
Michael J. Audino ◽  
Anthony P. Parker
Keyword(s):  
Residual Stress ◽  
Yield Strength ◽  
Yield Criterion ◽  
Axial Stress ◽  
Design Procedure ◽  
Pressure Vessels ◽  
Pressure Measurements ◽  
Strain Rate Effects ◽  
Axial Residual Stress ◽  
Von Mises

Yield pressure corresponding to a small permanent OD strain was measured in quasi-static laboratory tests of autofrettaged ASTM A723 steel cannon pressure vessels. Yield pressure was found to be a consistent ratio of the yield strength measured from specimens located in close proximity to the area of observed yielding. Yield pressure measurements for dynamic cannon firing with typically a 5-ms pressure pulse duration gave 14% higher yield pressures, attributed to strain rate effects on plastic deformation. Calculated Von Mises yield pressure for the laboratory test conditions, including the Bauschinger-modified ID residual stress and open-end vessel conditions, agreed with measured yield pressure within 3–5%. Calculated yield pressure was found to be insensitive to the value of axial residual stress, since axial stress is the intermediate value in the Von Mises yield criterion. A description of yield pressure normalized by yield strength was given for autofrettaged A723 open-end pressure vessels over a range of wall ratio and degree of autofrettage, including effects of Bauschinger-modified residual stress. This description of yield pressure is proposed as a design procedure for cannons and other pressure vessels.

Estimation of the Stresses in Rotational Autofrettage of Thick-Walled Pressure Vessels Using von Mises Yield Criterion

2021 ◽  
Author(s):  
S. M. Kamal ◽  
Faruque Aziz
Keyword(s):  
Plane Strain ◽  
Yield Criterion ◽  
Pressure Vessels ◽  
Flow Rule ◽  
Stress Distributions ◽  
Von Mises Yield Criterion ◽  
Potential Methods ◽  
Von Mises ◽  
Associated Flow Rule ◽  
Theoretical Analyses

Abstract Rotational autofrettage is one of the recently proposed potential methods for eliminating the in-service yielding of thick-walled cylindrical pressure vessels. A few researchers have studied the feasibility of the process theoretically, and asserted certain advantages over the practicing hydraulic and swage autofrettage processes. In the literature, all theoretical analyses on the rotational autofrettage are based on the Tresca yield criterion and its associated flow rule, along with the assumption of different plane end conditions (plane strain and generalized plane strain). In this paper, an analysis of the rotational autofrettage of cylindrical vessel is attempted incorporating von Mises yield criterion. The plane strain condition is used for the analysis. A numerical shooting method is used to solve the governing differential equations providing the elastic-plastic stress distributions in the cylinder during loading. The present procedure is numerically experimented for a typical AH36 pressure vessel. It is found that the achievable level of the maximum stress pressure of the rotationally autofrettaged vessel is 74.46% higher than that of its non-autofrettaged counterpart for an overstrain level of 46.7%.

Model Error Assessment of Burst Capacity Models for Defect-Free Pipes

2012 ◽  
Author(s):  
W. Zhou ◽  
G. (Terry) Huang
Keyword(s):  
Structural Reliability ◽  
Prediction Models ◽  
Yield Criterion ◽  
Limit State ◽  
Model Error ◽  
Pressure Vessels ◽  
Strain Hardening Exponent ◽  
Model Errors ◽  
Reliability Based Design ◽  
Von Mises

The model errors associated with 19 burst pressure prediction models for defect-free thin-walled pipes are evaluated using a total of 76 full-scale burst test data of perfect pipes and pressure vessels collected from the literature. The considered models are based on the Tresca yield criterion, the von Mises yield criterion, or the average shear stress yield criterion. The probabilistic characteristics of the model error, i.e. the mean, coefficient of variation and best-fit probability distribution, are obtained based on the test-to-predicted ratios. The applicability of an empirical equation for estimating the strain hardening exponent in the burst capacity models is also evaluated. The model errors obtained in this study can be used in the structural reliability analysis of energy pipelines with respect to the limit state of burst of defect-free pipes and will facilitate the reliability-based design and assessment of pipelines.

Safety Assessment of Pressure Vessels in Service for More Than 20 Years

2020 ◽  
Author(s):  
Chen Xuedong ◽  
Fan Zhichao ◽  
Dong Jie ◽  
Ai Zhibin ◽  
Hu Mingdong
Keyword(s):  
Pressure Vessel ◽  
Failure Modes ◽  
Experimental Studies ◽  
Safety Evaluation ◽  
Pressure Vessels ◽  
Time Dependent ◽  
Economic Losses ◽  
Safety Specification ◽  
Pressure Swing ◽  
Dependent Failure

Abstract In recent years, a large number of pressure vessels for the petrochemical plants built in China in the 20th century have been in service for more than 20 years. The Chinese pressure vessel safety specification TSG 21-2016 “Supervision Regulation on Safety Technology for Stationary Pressure Vessel” stipulates that if the pressure vessels without definite design lives have been in service for more than 20 years, they shall be considered to have reached the design service lives. For these pressure vessels, if they are all blindly scrapped, it will cause huge economic losses. However, if they continue to be used blindly, it may bring great safety risks. In this paper, the failure mode, mechanism and damage evolution law are analyzed through a number of failure accident investigations and experimental studies, for typical pressure vessels such as large LPG spherical tanks, pressure swing adsorbers and coke drums. The classification method of pressure vessel for the time-independent and time-dependent failure modes has been proposed. As for the pressure vessels with time-independent failure modes, the principle to determine target life, and the strategy of inspection and maintenance have been proposed. While for the time-dependent failure modes, the safety evaluation and remaining life prediction methods for the pressure vessels with and without defects have been provided. Finally, the advices on amendment to the relevant regulations on pressure vessels have been proposed. The research findings could provide guidance for rationally determining the safety grades and scientifically extending the service lives of pressure vessels.

Application of Multi-Monitoring Information for Bridge Safety Evaluation

2012 ◽  
Vol 479-481 ◽  
pp. 493-496
Author(s):  
Yen Jen Lee ◽  
Jet Chau Wen ◽  
Chern Hwa Chen ◽  
Yuh Yi Lin
Keyword(s):  
Structural Damage ◽  
Safety Management ◽  
Safety Evaluation ◽  
Structural Safety ◽  
Bridge Health Monitoring ◽  
Stay Cables ◽  
Bridge Safety ◽  
Wind Vibration ◽  
Main Girder

Due to large flexibility in cable-stayed bridges, vibrations induced by seismic, traffic and wind loads are more significant than those in other types of bridges. These vibrations may cause structural damage, such as fatigue in stay cables, large deflection in main girder, etc. The objective of this paper is to investigate long-term dynamic characteristics of the Kao Ping Hsi cable-stayed bridge subjected to different external force conditions by using a bridge health monitoring system (BHMS). The bridge has been bearing the loads of traffic for more than a decade. To ensure the safety of the Bridge, the Bureau has developed a BHMS for the long-term monitoring of the overall structural safety over the entire operation stage in terms of seismic response, wind resisting response and cable vibration, as well as travel comfort. The BHMS will provide multi-alarm information for the study of bridge safety management and maintenance in relation to seismic activities, wind vibration and traffic.

The Impact of the Bauschinger Effect on Stress Concentrations and Stress Intensity Factors for Eroded Autofrettaged Thick Cylindrical Pressure Vessels

2012 ◽  
Vol 134 (2) ◽  
Author(s):  
Q. Ma ◽  
C. Levy ◽  
M. Perl
Keyword(s):  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Bauschinger Effect ◽  
Thermal Loading ◽  
Yield Criterion ◽  
Pressure Vessels ◽  
Intensity Factors ◽  
Stress Concentrations ◽  
Von Mises ◽  
The Impact

Our previous studies have shown that stress intensity factors (SIFs) are influenced considerably from the presence of the Bauschinger Effect (BE) in thick-walled pressurized cracked cylinders. For some types of pressure vessels, such as gun barrels, working in corrosive environment, in addition to acute temperature gradients and repetitive high-pressure impulses, erosions can be practically induced. Those erosions cause stress concentration at the bore, where cracks can readily initiate and propagate. In this study, the BE on the SIFs will be investigated for a crack emanating from an erosion’s deepest point in a multiply eroded autofrettaged, pressurized thick-walled cylinder. A commercial finite element package, ansys, was employed to perform this type of analysis. A two-dimensional model, analogous to the authors’ previous studies, has been adopted for this new investigation. Autofrettage with and without BE, based on von Mises yield criterion, is simulated by thermal loading and the SIFs are determined by the nodal displacement method. The SIFs are evaluated for a variety of relative crack lengths, a0/t = 0.01–0.45 emanating from the tip of the erosion of different geometries including (a) semicircular erosions of relative depths of 1%–10% of the cylinder’s wall thickness, t; (b) arc erosions for several dimensionless radii of curvature, r′/t = 0.05–0.4; and (c) semi-elliptical erosions with ellipticities of d/h = 0.5–1.5, and erosion span angle, α, from 6 deg to 360 deg. The effective SIFs for relatively short cracks are found to be increased by the presence of the erosion and further increased due to the BE, which may result in a significant decrease in the vessel’s fatigue life. Deep cracks are found to be almost unaffected by the erosion, but are considerably affected by BE.

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