Chithranjan Nadarajah - Academia.edu (original) (raw)

Papers by Chithranjan Nadarajah

Research paper thumbnail of Elevated Temperature Analysis in BPV Code Section VIII Division 2 Part 5

Volume 3: Design and Analysis, 2016

The Working Group on Design by Analysis in collaboration with the Working Group on Elevated Tempe... more The Working Group on Design by Analysis in collaboration with the Working Group on Elevated Temperature Construction has developed a proposal for elevated temperature analysis in the ASME Boiler and Pressure Vessel Code Section VIII Division 2 Part 5, Design by Analysis. Elevated temperature is defined as the temperature where the allowable stress is time-dependent, that is, controlled by creep. The proposal is divided into the potential failure modes: rupture, ratcheting, fatigue, buckling, and service conditions. Linear elastic and inelastic analysis options rely on published approaches. The focus of the presentation will be on the Linear Elastic analysis options which include a fatigue screening, a ratcheting assessment, and an assessment for burst. Multiple conditions are allowed in the analysis. The proposed rules will be presented.

Research paper thumbnail of Comparison of Candidate Steady Loading Elevated Temperature Design-by-Analysis Methods

Volume 2: Computer Technology and Bolted Joints; Design and Analysis, 2021

Design-by-Analysis is distinguished from Design-by-Formula or Design-by-Rule in that specific fai... more Design-by-Analysis is distinguished from Design-by-Formula or Design-by-Rule in that specific failure modes are identified, and detailed analysis of each failure mode is compared to criteria specific to each failure mode. Several ASME Boiler and Pressure Vessel code committees continue to work on design-by-analysis methods in the elevated temperature range, where creep rupture is a failure mode with steady loading. The Subgroup on Elevated Temperature Design, which reports to Section I and Section VIII and collaborates with Section III, has been evaluating eight different analysis methods for six example problems. The two Design-by-Formula methods are from Section I and Section VIII Division 1 and the Design-by-Analysis methods are (1) Linear Elastic Analysis with revised stress limits, (2) Isochronous Curve Limit Load, (3) STP-PT-070 Limit Load Analysis, (4) Detailed Inelastic Methods using the MPC Omega creep models, (5) ASME CC2843 (simplified NH method),and (6) Section III Divis...

Research paper thumbnail of A Better Way to Support Horizontal Pressure Vessels Subject to Thermal Loading

ASME 1997 Turbo Asia Conference, 1997

When storing liquids at high temperature, in horizontal vessels, the current design methods aim t... more When storing liquids at high temperature, in horizontal vessels, the current design methods aim to minimise the thermal stresses by introducing a sliding surface at the base of one of the twin saddle supports. However, regular site maintenance is required to ensure that adequate sliding is achieved. This may be difficult and costly to carry out. The aim of the present work, therefore, is to dispense with the sliding support and to provide saddle designs which although fixed to the platform, or foundation, do not result in the storage/pressure vessel being overstressed when thermal loading occurs. The paper provides general recommendations for the most appropriate caddie geometries, and details the way in which 'Design by Analysis' and 'Fatigue Life Assessments' may be carried out using the stresses which arise from these designs. NOTATION A length of vessel beyond saddle-overhang. I', breadth of the saddle top plate in axial direction. dp basic saddle width. E • elastic modulus of the vessel and saddle material. height of saddle, measured from nadir of vessel to base plate (see Figs 1 &2). length of vessel between supports. mean radius of the vessel. wall thickness of vessel. thickness of saddle web and stiffeners. stress intensity (i.e. max principal stress difference) AT temperature differential. extended width of saddle top plate. a linear coefficient of thermal expansion of vessel and saddle material.

Research paper thumbnail of Horizontal vessels on fixed supports used for storing high-temperature liquid: an experimental validation of finite element modelling

The Journal of Strain Analysis for Engineering Design, 1999

ABSTRACT Horizontal cylindrical storage vessels are normally supported on two saddles. When used ... more ABSTRACT Horizontal cylindrical storage vessels are normally supported on two saddles. When used for storing high-temperature fluid, high values of thermal stress can be avoided by providing one of the supports with a sliding base. However, this ideal may be difficult to achieve in practice and vessels are sometimes found where both saddles have become rigidly fixed to the foundation. In view of this there may be certain advantages in dispensing with the concept of a sliding saddle support altogether and installing the vessels with both saddles permanently fixed to the foundation. Where this is adopted, the vessels and saddles must be designed to carry the thermal stresses that arise from the imposed restraint of the saddle base. Since this procedure is outside normal practice, as set out in the existing pressure vessel codes and standards, it is necessary to undertake detailed analytical investigations, say, using finite element analysis (FEA), to establish the behaviour of the vessels when this approach is used. In order to validate the predictions of temperature and stress obtained from the FEA used in the investigations, it was considered important to carry out some experimental work. This paper reports the techniques used and describes two experimental procedures which were performed on vessels mounted on two quite different saddle designs, both of which are widely used in industry.

Research paper thumbnail of The Support of Horizontal Vessels Containing High-Temperature Fluids—A Design Study

Journal of Pressure Vessel Technology, 1998

This paper investigates the behavior of horizontal cylindrical vessels, subjected to thermal load... more This paper investigates the behavior of horizontal cylindrical vessels, subjected to thermal loading by high-temperature fluid, where the saddles are fixed to the supporting structure. In order to determine an optimum saddle design, three widely used saddle configurations, with differing saddle heights and top saddle plate extensions, are explored. Thereafter, one of the saddle designs is selected to illustrate a decoupling procedure, for the radial and axial expansions, whereby design charts are obtained to derive the maximum stress values for a range of vessel geometries. The finite element approach, using linear elastic, small displacement analysis, is used throughout.

Research paper thumbnail of Biaxial Ratcheting and Cyclic Plasticity for Bree-Type Loading—Part I: Finite Element Analysis

Journal of Pressure Vessel Technology, 1996

The Bree diagram has been incorporated in the ASME B&PV Code in the elevated temperature Code Cas... more The Bree diagram has been incorporated in the ASME B&PV Code in the elevated temperature Code Case N47 as a design approach for limiting strain accumulation in cylinders subjected to cyclic thermal loadings under sustained primary stress. Since the Bree diagram is based upon uniaxial-stress model, it is pertinent to examine the influence of biaxial stresses on strain growth and cyclic stress-strain hysteresis response. The results of inelastic analyses presented in this paper showed that ratcheting and hysteresis behavior may also occur in the axial direction in addition to the hoop direction. Results of almost 100 load cases were presented to clarify the influence of biaxial membrane and thermal bending stresses on the structural behavior. A design approach for the assessment of this type of problem was suggested which utilizes these results.

Research paper thumbnail of An alternative way to support horizontal pressure vessels subject to thermal loading

International Journal of Pressure Vessels and Piping, 1998

ABSTRACT When storing liquids at high temperature in horizontal vessels, the current design metho... more ABSTRACT When storing liquids at high temperature in horizontal vessels, the current design methods aim to minimise the thermal stresses by introducing a sliding surface at the base of one of the twin saddle supports. However, regular site maintenance is required to ensure that adequate sliding is achieved. This may be difficult and costly to carry out. The aim of the present work, therefore, is to dispense with the sliding support and to provide saddle designs which, although fixed to the platform or foundation, do not result in the storage/pressure vessel being overstressed when thermal loading occurs. This paper provides general recommendations for the most appropriate saddle geometries, and details the way in which design-by-analysis and fatigue-life- assessments may be carried out using the stresses that arise from these designs.

Research paper thumbnail of The radial loading of cylindrical vessels—influence of large displacements

International Journal of Pressure Vessels and Piping, 1996

The present version of the Pressure Vessel Standard, BS 5500' restricts the design of the local l... more The present version of the Pressure Vessel Standard, BS 5500' restricts the design of the local load type situations to certain vessel and attachment geometries. This paper identifies the main underlying reasons for these restrictions; which are a limitation of the deflection and rotations by the use of small displacement analysis, and a neglect of the rigidity of the attachment. This paper addresses the influence of the attachment rigidity by considering a number of attachment thicknesses. The companion paper' considers the large displacement phenomenon and brings the two effects together in a design approach for these components. The method proposed provides a series of stress and displacement correction factors whereby the existing British Standard design method can be modified to cover the entire range of geometries up to (C,/R) = 0.25 for all values of (R/T) up to 250.

Research paper thumbnail of Elastic Allowable Stress Basis for Elevated Temperature Design in the Creep Regime

Volume 3: Design and Analysis, 2016

Research paper thumbnail of Modeling Refractory Stiffness for Piping Flexibility Analysis

Volume 2: Computer Technology and Bolted Joints; Design and Analysis

Refractory is commonly used in pipes for cold wall design. Generally, to analyze refractory lined... more Refractory is commonly used in pipes for cold wall design. Generally, to analyze refractory lined piping, a piping stress analysis is done using commercially available piping flexibility analysis software. In the stress analysis, the refractory weight and stiffnesses are included in the piping model. From the piping analysis, the calculated sustained and expansion stresses are compared with ASME B31.3 [1] allowable stresses and the forces and moments from the analysis are used in the design of attached equipment (vessel nozzle, valves, expansion joints etc.) piping restraints and supports. In this paper it will be shown that for a piping stress analysis, using the combined stiffness of the refractory and pipe material on the straight section of the pipe is satisfactory but when it is used on the bends, it will result in un-conservative resultant forces and moments from thermal expansion. To obtain satisfactory resultant forces and moments, the calculated refractory stiffnesses on th...

Research paper thumbnail of An Analytical Solution for Calculating Stresses on Full Encirclement Sleeves Used on Pipes and Pressure Vessels

Volume 3: Design and Analysis, 2015

Welded full encirclement sleeve repairs are used regularly in petrochemical industries as repairs... more Welded full encirclement sleeve repairs are used regularly in petrochemical industries as repairs for piping and pressure vessels. This publication describes a proposed methodology for calculating the stresses on a welded full encirclement sleeve using a simple analytical approximation. The analytical results are compared with finite element results and are found to be in reasonable.

Research paper thumbnail of An Analytical Solution Based on Shell Theory for Calculating Stresses on Full Encirclement Sleeves Used on Pipes and Pressure Vessels

Research paper thumbnail of A Parametric Study of ASME B16.5 Flanges Which Has Experienced Flange Face Corrosion

Pressure Vessel and Piping Codes and Standards, 2004

Weld neck flanges on piping systems are susceptible to flange face corrosion when they are expose... more Weld neck flanges on piping systems are susceptible to flange face corrosion when they are exposed to corrosive environments. This paper examines the maximum amount of corrosion a weld neck flange face could tolerate without loosing structural integrity and hence the flange is fit for service. A parametric study using finite element method was used to examine the entire range of weld neck flanges listed in ASME B16.5 Code, Pipe Flanges and Flanged Fittings. From the study, a number of tables were developed limiting the amount of corrosion for the various classes and sizes of flanges.Copyright © 2004 by ASME

Research paper thumbnail of Coker Inlet Design to Minimize Effects of Impingement

Research paper thumbnail of Process for Reactor Catalyst Loading

Research paper thumbnail of Apparatus and Systems Having an Adsorbent Contactor and Swing Adsorption Processes Related Thereto

Research paper thumbnail of An Analytical Solution for Calculating Stresses on Lap Patches Used on Pipes and Pressure Vessels

Volume 3: Design and Analysis, 2008

Lap patch repairs are used regularly in petrochemical industries as temporary repairs for short t... more Lap patch repairs are used regularly in petrochemical industries as temporary repairs for short term operations. In this paper a simple methodology is proposed on how to calculate the stresses on a lap patch using simple analytical approximation. The simple analytical results are compared with finite element results and they are found to be in reasonable agreement.

Research paper thumbnail of Simple Bounds on Limit Loads by Elastic Finite Element Analysis

Journal of Pressure Vessel Technology, 1993

A method for bounding limit loads by an iterative elastic continuum finite element analysis proce... more A method for bounding limit loads by an iterative elastic continuum finite element analysis procedure, referred to as the elastic compensation method, is proposed. A number of sample problems are considered, based on both exact solutions and finite element analysis, and it is concluded that the method may be used to obtain limit-load bounds for pressure vessel design by analysis applications with useful accuracy.

Research paper thumbnail of Buckling of Cylinders due to External Pressure: Experimental Work Compared With Finite Element Stress Analysis

Volume 3: Design and Analysis, 2020

The current design by analysis for protection against collapse from buckling in ASME Section VIII... more The current design by analysis for protection against collapse from buckling in ASME Section VIII, Division 2, B&PV Code [8] has three different methods. However, these is no background bases for the three methods and analyst have found that the elastic plastic collapse analysis will give overly conservative results when compared with design by rule. Therefore, this study was undertaken to resolve this concern and develop a new procedure for buckling analysis to be implemented in the ASME Section VIII, Division 2, B&PV Code, Part 5.

Research paper thumbnail of Using Isochronous Method to Calculate Creep Damage in Pressure Vessel Components: Part 2

Volume 3B: Design and Analysis, 2017

This paper is Part 2 of two papers illustrating how isochronous stress strain curves can be used ... more This paper is Part 2 of two papers illustrating how isochronous stress strain curves can be used to calculate creep stresses and damage for pressure vessel components. Part 1 [1], illustrated the use of isochronous stress strain curves to obtain creep stresses and damages on two simple example problems which were solved using closed form solution. In Part 2, the isochronous method is implemented in finite element analysis to determine creep stresses and damages on pressure vessel components. Various different pressure vessel components are studied using this method and the results obtained using this method is compared time explicit Omega creep model. The results obtained from the isochronous method is found to be in good agreement with the time explicit Omega creep model.

Research paper thumbnail of Elevated Temperature Analysis in BPV Code Section VIII Division 2 Part 5

Volume 3: Design and Analysis, 2016

The Working Group on Design by Analysis in collaboration with the Working Group on Elevated Tempe... more The Working Group on Design by Analysis in collaboration with the Working Group on Elevated Temperature Construction has developed a proposal for elevated temperature analysis in the ASME Boiler and Pressure Vessel Code Section VIII Division 2 Part 5, Design by Analysis. Elevated temperature is defined as the temperature where the allowable stress is time-dependent, that is, controlled by creep. The proposal is divided into the potential failure modes: rupture, ratcheting, fatigue, buckling, and service conditions. Linear elastic and inelastic analysis options rely on published approaches. The focus of the presentation will be on the Linear Elastic analysis options which include a fatigue screening, a ratcheting assessment, and an assessment for burst. Multiple conditions are allowed in the analysis. The proposed rules will be presented.

Research paper thumbnail of Comparison of Candidate Steady Loading Elevated Temperature Design-by-Analysis Methods

Volume 2: Computer Technology and Bolted Joints; Design and Analysis, 2021

Design-by-Analysis is distinguished from Design-by-Formula or Design-by-Rule in that specific fai... more Design-by-Analysis is distinguished from Design-by-Formula or Design-by-Rule in that specific failure modes are identified, and detailed analysis of each failure mode is compared to criteria specific to each failure mode. Several ASME Boiler and Pressure Vessel code committees continue to work on design-by-analysis methods in the elevated temperature range, where creep rupture is a failure mode with steady loading. The Subgroup on Elevated Temperature Design, which reports to Section I and Section VIII and collaborates with Section III, has been evaluating eight different analysis methods for six example problems. The two Design-by-Formula methods are from Section I and Section VIII Division 1 and the Design-by-Analysis methods are (1) Linear Elastic Analysis with revised stress limits, (2) Isochronous Curve Limit Load, (3) STP-PT-070 Limit Load Analysis, (4) Detailed Inelastic Methods using the MPC Omega creep models, (5) ASME CC2843 (simplified NH method),and (6) Section III Divis...

Research paper thumbnail of A Better Way to Support Horizontal Pressure Vessels Subject to Thermal Loading

ASME 1997 Turbo Asia Conference, 1997

When storing liquids at high temperature, in horizontal vessels, the current design methods aim t... more When storing liquids at high temperature, in horizontal vessels, the current design methods aim to minimise the thermal stresses by introducing a sliding surface at the base of one of the twin saddle supports. However, regular site maintenance is required to ensure that adequate sliding is achieved. This may be difficult and costly to carry out. The aim of the present work, therefore, is to dispense with the sliding support and to provide saddle designs which although fixed to the platform, or foundation, do not result in the storage/pressure vessel being overstressed when thermal loading occurs. The paper provides general recommendations for the most appropriate caddie geometries, and details the way in which 'Design by Analysis' and 'Fatigue Life Assessments' may be carried out using the stresses which arise from these designs. NOTATION A length of vessel beyond saddle-overhang. I', breadth of the saddle top plate in axial direction. dp basic saddle width. E • elastic modulus of the vessel and saddle material. height of saddle, measured from nadir of vessel to base plate (see Figs 1 &2). length of vessel between supports. mean radius of the vessel. wall thickness of vessel. thickness of saddle web and stiffeners. stress intensity (i.e. max principal stress difference) AT temperature differential. extended width of saddle top plate. a linear coefficient of thermal expansion of vessel and saddle material.

Research paper thumbnail of Horizontal vessels on fixed supports used for storing high-temperature liquid: an experimental validation of finite element modelling

The Journal of Strain Analysis for Engineering Design, 1999

ABSTRACT Horizontal cylindrical storage vessels are normally supported on two saddles. When used ... more ABSTRACT Horizontal cylindrical storage vessels are normally supported on two saddles. When used for storing high-temperature fluid, high values of thermal stress can be avoided by providing one of the supports with a sliding base. However, this ideal may be difficult to achieve in practice and vessels are sometimes found where both saddles have become rigidly fixed to the foundation. In view of this there may be certain advantages in dispensing with the concept of a sliding saddle support altogether and installing the vessels with both saddles permanently fixed to the foundation. Where this is adopted, the vessels and saddles must be designed to carry the thermal stresses that arise from the imposed restraint of the saddle base. Since this procedure is outside normal practice, as set out in the existing pressure vessel codes and standards, it is necessary to undertake detailed analytical investigations, say, using finite element analysis (FEA), to establish the behaviour of the vessels when this approach is used. In order to validate the predictions of temperature and stress obtained from the FEA used in the investigations, it was considered important to carry out some experimental work. This paper reports the techniques used and describes two experimental procedures which were performed on vessels mounted on two quite different saddle designs, both of which are widely used in industry.

Research paper thumbnail of The Support of Horizontal Vessels Containing High-Temperature Fluids—A Design Study

Journal of Pressure Vessel Technology, 1998

This paper investigates the behavior of horizontal cylindrical vessels, subjected to thermal load... more This paper investigates the behavior of horizontal cylindrical vessels, subjected to thermal loading by high-temperature fluid, where the saddles are fixed to the supporting structure. In order to determine an optimum saddle design, three widely used saddle configurations, with differing saddle heights and top saddle plate extensions, are explored. Thereafter, one of the saddle designs is selected to illustrate a decoupling procedure, for the radial and axial expansions, whereby design charts are obtained to derive the maximum stress values for a range of vessel geometries. The finite element approach, using linear elastic, small displacement analysis, is used throughout.

Research paper thumbnail of Biaxial Ratcheting and Cyclic Plasticity for Bree-Type Loading—Part I: Finite Element Analysis

Journal of Pressure Vessel Technology, 1996

The Bree diagram has been incorporated in the ASME B&PV Code in the elevated temperature Code Cas... more The Bree diagram has been incorporated in the ASME B&PV Code in the elevated temperature Code Case N47 as a design approach for limiting strain accumulation in cylinders subjected to cyclic thermal loadings under sustained primary stress. Since the Bree diagram is based upon uniaxial-stress model, it is pertinent to examine the influence of biaxial stresses on strain growth and cyclic stress-strain hysteresis response. The results of inelastic analyses presented in this paper showed that ratcheting and hysteresis behavior may also occur in the axial direction in addition to the hoop direction. Results of almost 100 load cases were presented to clarify the influence of biaxial membrane and thermal bending stresses on the structural behavior. A design approach for the assessment of this type of problem was suggested which utilizes these results.

Research paper thumbnail of An alternative way to support horizontal pressure vessels subject to thermal loading

International Journal of Pressure Vessels and Piping, 1998

ABSTRACT When storing liquids at high temperature in horizontal vessels, the current design metho... more ABSTRACT When storing liquids at high temperature in horizontal vessels, the current design methods aim to minimise the thermal stresses by introducing a sliding surface at the base of one of the twin saddle supports. However, regular site maintenance is required to ensure that adequate sliding is achieved. This may be difficult and costly to carry out. The aim of the present work, therefore, is to dispense with the sliding support and to provide saddle designs which, although fixed to the platform or foundation, do not result in the storage/pressure vessel being overstressed when thermal loading occurs. This paper provides general recommendations for the most appropriate saddle geometries, and details the way in which design-by-analysis and fatigue-life- assessments may be carried out using the stresses that arise from these designs.

Research paper thumbnail of The radial loading of cylindrical vessels—influence of large displacements

International Journal of Pressure Vessels and Piping, 1996

The present version of the Pressure Vessel Standard, BS 5500' restricts the design of the local l... more The present version of the Pressure Vessel Standard, BS 5500' restricts the design of the local load type situations to certain vessel and attachment geometries. This paper identifies the main underlying reasons for these restrictions; which are a limitation of the deflection and rotations by the use of small displacement analysis, and a neglect of the rigidity of the attachment. This paper addresses the influence of the attachment rigidity by considering a number of attachment thicknesses. The companion paper' considers the large displacement phenomenon and brings the two effects together in a design approach for these components. The method proposed provides a series of stress and displacement correction factors whereby the existing British Standard design method can be modified to cover the entire range of geometries up to (C,/R) = 0.25 for all values of (R/T) up to 250.

Research paper thumbnail of Elastic Allowable Stress Basis for Elevated Temperature Design in the Creep Regime

Volume 3: Design and Analysis, 2016

Research paper thumbnail of Modeling Refractory Stiffness for Piping Flexibility Analysis

Volume 2: Computer Technology and Bolted Joints; Design and Analysis

Refractory is commonly used in pipes for cold wall design. Generally, to analyze refractory lined... more Refractory is commonly used in pipes for cold wall design. Generally, to analyze refractory lined piping, a piping stress analysis is done using commercially available piping flexibility analysis software. In the stress analysis, the refractory weight and stiffnesses are included in the piping model. From the piping analysis, the calculated sustained and expansion stresses are compared with ASME B31.3 [1] allowable stresses and the forces and moments from the analysis are used in the design of attached equipment (vessel nozzle, valves, expansion joints etc.) piping restraints and supports. In this paper it will be shown that for a piping stress analysis, using the combined stiffness of the refractory and pipe material on the straight section of the pipe is satisfactory but when it is used on the bends, it will result in un-conservative resultant forces and moments from thermal expansion. To obtain satisfactory resultant forces and moments, the calculated refractory stiffnesses on th...

Research paper thumbnail of An Analytical Solution for Calculating Stresses on Full Encirclement Sleeves Used on Pipes and Pressure Vessels

Volume 3: Design and Analysis, 2015

Welded full encirclement sleeve repairs are used regularly in petrochemical industries as repairs... more Welded full encirclement sleeve repairs are used regularly in petrochemical industries as repairs for piping and pressure vessels. This publication describes a proposed methodology for calculating the stresses on a welded full encirclement sleeve using a simple analytical approximation. The analytical results are compared with finite element results and are found to be in reasonable.

Research paper thumbnail of An Analytical Solution Based on Shell Theory for Calculating Stresses on Full Encirclement Sleeves Used on Pipes and Pressure Vessels

Research paper thumbnail of A Parametric Study of ASME B16.5 Flanges Which Has Experienced Flange Face Corrosion

Pressure Vessel and Piping Codes and Standards, 2004

Weld neck flanges on piping systems are susceptible to flange face corrosion when they are expose... more Weld neck flanges on piping systems are susceptible to flange face corrosion when they are exposed to corrosive environments. This paper examines the maximum amount of corrosion a weld neck flange face could tolerate without loosing structural integrity and hence the flange is fit for service. A parametric study using finite element method was used to examine the entire range of weld neck flanges listed in ASME B16.5 Code, Pipe Flanges and Flanged Fittings. From the study, a number of tables were developed limiting the amount of corrosion for the various classes and sizes of flanges.Copyright © 2004 by ASME

Research paper thumbnail of Coker Inlet Design to Minimize Effects of Impingement

Research paper thumbnail of Process for Reactor Catalyst Loading

Research paper thumbnail of Apparatus and Systems Having an Adsorbent Contactor and Swing Adsorption Processes Related Thereto

Research paper thumbnail of An Analytical Solution for Calculating Stresses on Lap Patches Used on Pipes and Pressure Vessels

Volume 3: Design and Analysis, 2008

Lap patch repairs are used regularly in petrochemical industries as temporary repairs for short t... more Lap patch repairs are used regularly in petrochemical industries as temporary repairs for short term operations. In this paper a simple methodology is proposed on how to calculate the stresses on a lap patch using simple analytical approximation. The simple analytical results are compared with finite element results and they are found to be in reasonable agreement.

Research paper thumbnail of Simple Bounds on Limit Loads by Elastic Finite Element Analysis

Journal of Pressure Vessel Technology, 1993

A method for bounding limit loads by an iterative elastic continuum finite element analysis proce... more A method for bounding limit loads by an iterative elastic continuum finite element analysis procedure, referred to as the elastic compensation method, is proposed. A number of sample problems are considered, based on both exact solutions and finite element analysis, and it is concluded that the method may be used to obtain limit-load bounds for pressure vessel design by analysis applications with useful accuracy.

Research paper thumbnail of Buckling of Cylinders due to External Pressure: Experimental Work Compared With Finite Element Stress Analysis

Volume 3: Design and Analysis, 2020

The current design by analysis for protection against collapse from buckling in ASME Section VIII... more The current design by analysis for protection against collapse from buckling in ASME Section VIII, Division 2, B&PV Code [8] has three different methods. However, these is no background bases for the three methods and analyst have found that the elastic plastic collapse analysis will give overly conservative results when compared with design by rule. Therefore, this study was undertaken to resolve this concern and develop a new procedure for buckling analysis to be implemented in the ASME Section VIII, Division 2, B&PV Code, Part 5.

Research paper thumbnail of Using Isochronous Method to Calculate Creep Damage in Pressure Vessel Components: Part 2

Volume 3B: Design and Analysis, 2017

This paper is Part 2 of two papers illustrating how isochronous stress strain curves can be used ... more This paper is Part 2 of two papers illustrating how isochronous stress strain curves can be used to calculate creep stresses and damage for pressure vessel components. Part 1 [1], illustrated the use of isochronous stress strain curves to obtain creep stresses and damages on two simple example problems which were solved using closed form solution. In Part 2, the isochronous method is implemented in finite element analysis to determine creep stresses and damages on pressure vessel components. Various different pressure vessel components are studied using this method and the results obtained using this method is compared time explicit Omega creep model. The results obtained from the isochronous method is found to be in good agreement with the time explicit Omega creep model.