Comparative study of Pressure Vessel Design Software – Case Study for Fatigue Analysis

Objective
The purpose of this study is to perform a detailed comparison of pressure vessel design workflows using two different software tools – VCLAVIS and a leading industry-standard software (latest available as of April 2025). The focus is specifically on the design of vessels subject to fatigue loads, which involve long-term exposure to elevated temperatures, as outlined in the EN 13445, the European standard for unfired pressure vessels.

Designing for fatigue presents unique challenges, particularly under thermal and pressure cycling. These include managing cyclic stress-dependent material behavior and setting fatigue strength factors for each joint type, as defined in standards such as EN 13445. Traditional software often falls short in these areas, leading to increased engineering hours, dependence on auxiliary spreadsheets, and manual intervention throughout the workflow.

This study evaluates how each software platform handles:
• Material property management and fatigue data input
• Fatigue calculations execution and results evaluation
• Code compliance checks and stability assessments
• Workflow automation and report generation

By applying the same design scenario across both tools, the study quantifies the time required for each task, identifies workflow bottlenecks, and evaluates each tool’s usability. The goal is to assess not only time efficiency but also the reliability and user-friendliness of each software when designing pressure vessels subjected to fatigue loading.

Sample vessel specifications
Cylindrical vessel with two torispherical heads per DIN28013 supported on saddles type BV per DIN28080, equipped with 2 lifting lugs per DIN28086 on shell. The following technical characteristics apply:

Design Data
Internal Design Pressure:	1 MPa
Internal Design Temperature:	250°C
External Design Pressure:	0.1 Mpa
External Design Temperature:	250°C
Corrosion Allowance:	1 mm
Fatigue design (simplified)	Pressure 0 to 0.5 Mpa for 10000 fluctuations, steady temperature

Dimensional Data
Component	Diameter	Thickness	Length	Material
Shell	OD=1500	T=16	L=5000	EN10028-2 P265GH
Heads	OD=1500	T=16 (af)	sf = 50	EN10028-2 P265GH
Skirt	OD=1500	T=10	L=2000	EN10028-2 P265GH

Example Nozzle Index (Nozzles with Pads)
Tag	Description	Dimension	Make	Nozzle material	Flange Rating	Flange material
1M	Manway	DN600	Plate 16mm	EN10028-2 P265GH	PN40	EN10222-2 P245GH
1N	Inlet	DN200	Pipe 12.7mm	EN10216-2 P265GH	PN40	EN10222-2 P245GH
2N	Outlet	DN200	Pipe 12.7mm	EN10216-2 P265GH	PN40	EN10222-2 P245GH
3N	Drain	DN50	Pipe 8.74mm	EN10216-2 P265GH	PN40	EN10222-2 P245GH
4N	Vent	DN50	Pipe 8.74mm	EN10216-2 P265GH	PN40	EN10222-2 P245GH

Design Execution Time: Industry Software vs. VCLAVIS
Industry software (2025 edition)
Examination Point		Time	Issues spotted
1	Find how to perform fatigue assessment	10 min	Applicable only on weld Joint Efficiency tabs. When accessed from the shell component, the GUI is not accessible on the head components. Overall poor GUI
2	Design of primary components	5 min	Typical
3	Set fatigue factors for main welds	10 min	Default values are not provided for weld class. User needs to search the Code for reference.
4	Set additional fatigue factors for head knuckles	20 min	Not exclusively provided. User needs to search the Code and possibly modify the circumferential weld class. Direct loss in software trust occurs. If user is unfamiliar with the Code, this could lead to grave error in the analysis.
5	Design of nozzles	20 min	No problems spotted there. Typically 5 min per nozzle
6	Set fatigue factors for nozzle to shell welds	10 min	Default values are not provided for weld class. User needs to search the Code for reference. Factor η has no option to override.
7	Set additional fatigue factors for pad to shell welds	10 min	Not exclusively provided. User needs to search the Code and possibly modify the nozzle weld class. Direct loss in software trust occurs. If user is unfamiliar with the Code, this could lead to grave error in the analysis.
8	Assign EN13445 stability scenarios	45 min	Not readily available in software, user needs to open the Code and manually set the software scenarios
9	Design for each stability case	45 min	User needs to prepare separate files for each scenario in order to verify the saddle components, since only operation (worst of seismic or wind) and test is presented.
10	Design saddles and lifting lugs	30 min	There are no readily available DIN saddle libraries. There is no readily available DIN lifting lug library.
11	Set fatigue factors for saddle and lifting lug to shell welds	15 min	Not provided. User needs to search the Code and possibly modify the shell weld class. Direct lost in software trust occurs. If user is unfamiliar with the Code, this could lead to grave error in the analysis.
12	Check fatigue results	80 min	Not provided in a single report. Each element has to be checked. Separate spreadsheets finally are required since many elements are not checked in fatigue.
Aggregate time:			300 min (5hrs)

Design Execution Time: Industry Software vs. VCLAVIS
VCLAVIS
Examination Point		Time	Solutions adopted
1	Find how to perform fatigue assessment	0 min	Readily available button, which performs fatigue analysis once you prepare the vessel
2	Design of primary components	5 min	Typical
3	Set fatigue factors for main welds	5 min	Automatically set by the software, only Code checking is required
4	Set additional fatigue factors for head knuckles	5 min	Automatically set by the software, only Code checking is required
5	Design of nozzles	20 min	Typically 5 min per nozzle
6	Set fatigue factors for nozzle to shell welds	5 min	Automatically set by the software, only Code checking is required
7	Set additional fatigue factors for pad to shell welds	5 min	Automatically set by the software, only Code checking is required
8	Assign EN13445 stability scenarios	0 min	Readily available
9	Design for each stability case	15 min	Vessel stability checks are automatically produced, but it takes some computing time to run and check all scenarios at once. However user does not need to perform any actions.
10	Design saddles and lifting lugs	10 min	Built in libraries
11	Set fatigue factors for saddle and lifting lug to shell welds	5 min	Automatically set by the software, only Code checking is required
12	Check fatigue results	10 min	Simply review the dedicated report
Aggregate time:			90 min (1.50 hrs)

Results
The comparative analysis highlights a pronounced efficiency gap between the two software tools. While the traditional industry software remains functional, it demands extensive manual effort – ranging from spreadsheet use and manual code verification to individual stability scenario assessments. In contrast, VCLAVIS Software for Pressure Vessel Design significantly enhances workflow with its integrated fatigue design features, automated stability checks, and consolidated reporting.

By reducing design time from 5 hours to just 1.5 hours—a 70% improvement—VCLAVIS not only accelerates the process but also minimizes the risk of human error, ensures consistent code compliance, and reallocates engineering effort toward more critical design decisions.

In today’s high-stakes engineering environments, where precision, speed, and regulatory adherence are essential, adopting a comprehensive and modern tool like VCLAVIS is more than advantageous – it is a strategic imperative.

Author: Dassa Isaak

Co-Founder & Lead Engineer at VCLAVIS O.E. Experienced Mechanical Engineer with a strong track record in the pressure vessel industry, specializing in the design and analysis of heat exchangers. Proficient in leading engineering tools including VCLAVIS.com, Autodesk Inventor, PVElite, VVD Ohmtech, and HTRI. Highly knowledgeable in international design codes and standards, including ASME, AD2000, PD5500, and EN13445. Holds a Master’s degree in Mechanical Engineering from the Aristotle University of Thessaloniki. Lead Engineer and Co-Founder of VCLAVIS.com, a specialized software platform for pressure vessel calculations.