When is finite element analysis required for pressure vessels?

FEA becomes necessary when: (1) Complex geometries exceed standard nozzle reinforcement rules, (2) Thermal shock loading creates stresses that can't be calculated by hand, (3) Fatigue evaluation is required per Division 1 Mandatory Appendix 46, (4) Elevated temperature service requires creep-fatigue analysis, (5) Non-standard configurations aren't covered by code formulas. When these conditions exist, ASME requires Design by Analysis using validated finite element methods that comply with Section VIII Division 2, Part 5 requirements.

What ASME codes does O'Donnell Consulting work with for pressure vessel FEA?

O'Donnell Consulting performs FEA to ASME Section VIII Division 1 (using Mandatory Appendix 46), Section VIII Division 2 (Design by Analysis per Part 5), and Section III Class 1 for nuclear vessels. We also reference API and AWS codes as applicable.

What types of analysis does O'Donnell perform for pressure vessels?

O'Donnell Consulting performs elastic stress analysis, elastic-plastic analysis, limit load analysis, thermal/transient analysis, fatigue analysis, creep-fatigue analysis, vibration analysis, seismic analysis, buckling analysis, and fracture analysis for pressure vessels and related equipment.

What is included in the FEA process for pressure vessels?

Our process involves six steps: (1) Initial Consultation & Code Review to determine applicable code sections and requirements, (2) Geometry Modeling & Mesh Development from your drawings, (3) Load Case Definition including all required combinations per Division 2 Part 5, (4) Analysis Execution using elastic or elastic-plastic methods, (5) Code Compliance Verification with stress classification and comparison to allowables, (6) Report Delivery with comprehensive documentation for authorized inspector review.

What is the difference between ASME Section VIII Division 1 and Division 2 finite element analysis?

ASME Section VIII Division 1 uses Design-by-Formula methods that work best for simple vessels without extreme geometric discontinuities. FEA under Division 1 is primarily used per Mandatory Appendix 46 for fatigue evaluation. Division 2 uses Design-by-Analysis methods with finite element analysis to accurately predict stresses in complex vessels, allowing for weight reduction while maintaining structural integrity. Division 2 Part 5 provides comprehensive requirements for stress classification, linearization procedures, and acceptance criteria that go beyond Division 1 capabilities.

When is finite element analysis required for pressure vessel design?

Finite element analysis becomes necessary when: (1) Complex geometries exceed standard nozzle reinforcement rules, (2) Thermal shock loading creates stresses that cannot be calculated by hand, (3) Fatigue evaluation is required per Division 1 Mandatory Appendix 46, (4) Elevated temperature service requires creep-fatigue analysis, or (5) Non-standard configurations are not covered by code formulas. When these conditions exist, ASME requires Design by Analysis using validated finite element methods that comply with Section VIII Division 2 Part 5 requirements.

What is stress linearization in ASME Section VIII Division 2 Part 5?

Stress linearization is a required procedure in ASME Division 2 Part 5 that separates the complex stress distribution from FEA into membrane, bending, and peak stress components. These components are extracted at critical locations and classified as primary, secondary, or peak stresses. Each stress category has different allowable limits based on the failure mode it represents. This systematic approach ensures that FEA results are properly evaluated against code acceptance criteria for structural integrity.

How long does a finite element analysis of a pressure vessel take?

The timeline for pressure vessel FEA depends on complexity but typically ranges from 2-6 weeks. Simple vessels with standard load cases may require 2-3 weeks, while complex geometries with multiple nozzles, thermal transients, and fatigue evaluation can take 4-6 weeks or longer. The process includes geometry modeling, mesh development and convergence verification, load case definition, analysis execution, stress classification, code compliance verification, and comprehensive report preparation. We provide estimated timelines during the initial consultation based on your specific requirements.

What information do I need to provide for pressure vessel FEA?

To perform FEA, we need: (1) Complete vessel geometry including drawings or CAD models showing all dimensions, nozzles, and attachments, (2) Material specifications and properties at operating temperatures, (3) Design pressure and temperature conditions, (4) Operating load cases including thermal transients, pressure cycles, and external loads, (5) Nozzle loads from connected piping if applicable, (6) Applicable ASME Code section and any jurisdictional requirements, and (7) Support configuration and boundary conditions. We will review these requirements during our initial consultation to ensure we have everything needed.

What is mesh convergence and why does it matter for ASME compliance?

Mesh convergence is the process of refining the finite element mesh until stress results stabilize and no longer change significantly with further refinement. This is critical for ASME compliance because Section VIII Division 2 requires that analysis results be mesh-independent and converged to acceptable tolerance levels. We systematically refine the mesh density, particularly in high-stress gradient areas near discontinuities, and document that results have converged. This verification ensures the analysis meets code requirements and provides reliable stress predictions for safety evaluation.

How much does finite element analysis for pressure vessels cost?

FEA costs vary significantly based on project complexity, analysis scope, and code requirements. Factors affecting cost include vessel geometry complexity, number of load cases, whether fatigue analysis is required, elevated temperature considerations, and level of documentation needed. Simple Division 1 Appendix 46 analyses may start around $5,000-10,000, while comprehensive Division 2 Part 5 analyses with multiple load combinations and fatigue evaluation typically range from $15,000-40,000 or more. Contact us at (412) 835-5007 for a project-specific quote based on your requirements.

What deliverables are included in an ASME FEA analysis report?

Our comprehensive FEA reports include: (1) Executive summary with conclusions and code compliance statement, (2) Complete problem definition including geometry, materials, and loading, (3) Finite element model description with mesh details and convergence verification, (4) Material properties at applicable temperatures, (5) Load case definitions and combinations per Division 2 requirements, (6) Stress results with contour plots showing distribution, (7) Stress linearization and classification documentation, (8) Code compliance calculations comparing stresses to allowable limits, (9) Fatigue evaluation if applicable, and (10) Detailed appendices with supporting calculations. Reports are formatted for review by authorized inspectors and third-party reviewers.

Can you perform FEA on existing pressure vessels for fitness-for-service evaluation?

Yes, we regularly perform FEA on existing pressure vessels for fitness-for-service (FFS) evaluations under API 579 and ASME FFS-1 standards. This includes evaluating vessels with discovered flaws, assessing remaining life for degraded components, analyzing vessels operating beyond original design conditions, and validating repair or alteration designs. Our engineers have over 30 years of experience in structural integrity assessments and can determine if vessels can safely continue operation, require repairs, or need replacement. We provide detailed FFS reports documenting the evaluation methodology and safety margins.

Finite Element Analysis (FEA) of Pressure Vessels to ASME BP&V

Q: What is the O'Donnell-Porowski Solution?

The O'Donnell-Porowski Solution is a methodology developed by Dr. William O'Donnell for elevated temperature design under cyclic thermal and pressure loading. This solution addresses creep-fatigue analysis and has been incorporated into ASME Code procedures.

Performing Finite Element Analysis (FEA) Design & Analysis of Pressure Vessels – Ensuring Integrity, Safety & Reliability

Summary

When standard pressure vessel design rules fall short – complex nozzle configurations, thermal shock loading, or geometries outside ASME Section VIII Division 1 limits – catastrophic failure becomes a real risk. A miscalculation could mean vessel rejection, project delays costing hundreds of thousands, or worse, field failures with liability consequences.

ASME Section VIII Division 1 provides design-by-formula methods (Design by Rule) that work for standard pressure vessel configurations. However, FEA becomes necessary when:

Complex geometries exceed standard nozzle reinforcement rules
Thermal shock loading creates stresses that can’t be calculated by hand
Fatigue evaluation is required per Division 1 Mandatory Appendix 46
Elevated temperature service requires creep-fatigue analysis
Non-standard configurations aren’t covered by code formulas

When these conditions exist, ASME requires Design by Analysis using validated finite element methods that comply with Section VIII Division 2, Part 5 requirements. Division 2 explicitly requires protection against Plastic Collapse, Local Failure, Buckling, Fatigue and Ratcheting.

For over 30 years, O’Donnell Consulting has performed finite element analysis of pressure vessels that withstand the scrutiny of authorized inspectors and third-party reviewers. We don’t just run FEA software – we ensure your analysis meets ASME B&PV requirements.

Finite Element Analysis (FEA) is Performed by Simulating Various Loading Conditions – Determining Stress and Strain Distributions and Potential Failure Points. This Provides a Comprehensive, Detailed Picture of how a Vessel, Nozzles & Support Structures will Behave under Various Loading. Read More about how FEA works.

Fatigue Analysis

Fatigue Analysis is performed per ASME Section III Class 1 and Section VIII Division 2. The fatigue design life evaluation procedures in Section III of the ASME Boiler and Pressure Vessel Code were originally developed in the U.S. Naval Nuclear Program. Those involved were Dr. William O’Donnell, (Bernie) Langer, W.E. (Bill) Cooper and James (Jim) Farr – who, in the late 1950’s and early 1960’s developed the initial formulation of this technology in the Tentative Structural Design Basis for Reactor Pressure Vessels, which became known as “SDB-63.” Section III of the ASME Code “Vessels in Nuclear Service” was the first to include specific Code rules to prevent low cycle fatigue failure.

In addition to developing the O’Donnell-Porowski Solution for elevated temperature design under cyclic thermal and pressure loading – Dr. O’Donnell has also made significant contributions to the ASME Subgroup on Fatigue Strength – and the ASME Subcommittee on Design. He has also written numerous publications on Design, Fatigue, Failure and Creep.

Our Engineers have over 30 years Experience in Finite Element Analysis – Performing Thermal/Transient, Structural, Creep, Vibration, Fatigue and Failure Evaluations. This includes a wide variety of Pressure Vessels in accordance with Section VIII, Division 1 and 2 of the ASME Boiler & Pressure Vessel Code – on Chemical Reactors, Accumulator Tanks, Autoclaves, PSA Vessels and Heat Exchangers. See more of our ASME Design/ Analysis Solutions.

Our Process Involves

Initial Consultation & Code Review
We review your design to determine applicable code section, identify analysis requirements, and establish acceptance criteria.
Geometry Modeling & Mesh Development
Create solid models from your drawings, develop appropriate mesh density based on stress gradients, verify mesh convergence per ASME requirements.
Load Case Definition
Define all required load combinations: pressure, thermal, dead weight, seismic, wind, nozzle loads, per Division 2 Part 5.
Analysis Execution
Perform elastic or elastic-plastic analysis as appropriate, extract stresses at critical locations, apply stress linearization procedures.
Code Compliance Verification
Classify stresses (primary, secondary, peak), compare to allowable limits, document compliance with Section VIII Division 2 criteria.
Report Delivery
Provide comprehensive analysis report documenting methodology, results, and code compliance for review.

Experience Includes

Linear/ Nonlinear FEA Analysis
Seismic, Vibration & Fatigue
Heat Transfer
Fracture Analysis
Thermal Cycling & Fatigue
Thermal / Transient
Buckling Analysis
Creep & Creep Fatigue
Fatigue / Failure Analysis

Applications Include:

Petrochemical
Transportation
Aerospace
Energy
Manufacturing
Oil / Gas
Military

In Addition to the following ASME Codes – We also Refer to Other Codes including API & AWS

B&PV Section VIII Div. 1 (Design & Fabrication of Pressure Vessels)
B&PV Section VIII Div. 2, Part 5 (Design by Analysis)
B&PV Section VIII Div. 3 (Alternative Rules for Construction of High-Pressure Vessels)

Give Us a Call to Discuss Your Engineering Challenges

Relevant Links

>> Tom O’Donnell, PE
>> FEA Design & Analysis of Chemical Tubular Reactor – To ASME Section VIII Code
>> Blog: Basics of Pressure Vessel Design
>> Blog: Common Mistakes in Pressure Vessel Design & Analysis
>> Blog: Description of Finite Element Analysis
>> Blog: Background of the ASME Code
>> Blog: Overview of ASME B&PV Design by Analysis
>> Blog: Introduction to Fatigue / Failure Analysis

Learn from the experience of others. Especially when one such “other” is Dr. William O’Donnell, PhD, PE, Founder and President of O’Donnell Consulting Engineers, Inc., and ASME “Engineer of the Year” – his 50 years of experience in analysis of components including fatigue and fracture safety evaluations and failure analyses are now comprised in this volume.

If you are interested learning more in Engineering Design, Manufacturing and Construction, as well as Failure Analysis, then this book is a must have!

$49.95*

* Does not include shipping, handling or tax