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Application to the WCFA-DFW

Payment of the WCFA-DFW

Time Schedule of the WCFA-DFW

Course Lecturer



Programme of the Workshop

The course is built in such a way, that no prior knowledge on fatigue analysis is needed. The first day is devoted to the design of welded structures entirely. The basic principles of the common fatigue damage estimation are described in the next day, while the content related to the fatigue analysis of weldments is extensively discussed in next two days. In order to better suit the needs of participants and to fit the course better to the level of their knowledge, several variants of the course are provided as shown in the table below.

Nov 13, 2017
V1 - Design Aspects
Z. Barsoum
V4 - Design And Fatigue Intro V6 - Complete Course V7 - Barsoum
Nov 14, 2017
V2 - Introduction To Fatigue
M. Růžička, J. Papuga, J. Jurenka
V5 - Complete Fatigue
Nov 15, 2017
V3 - Fatigue Analysis of Weldments
Z. Barsoum
V7 - Barsoum
Nov 16, 2017

Note: The following synopses of programs for individual days are just informatory, the detailed program will be released during September 2017.

Design Aspects (included in variants: Design and Fatigue Intro, Complete Course, Barsoum)

Welding Technology

  • Welding Technology
  • Welding terminology
  • Welding symbols and design drawings
  • Overview of welding processes
  • Materials and weld metallurgy

Design of Welded Structures

  • Basic theory of structural systems
  • Loads on structures
  • Introduction to the design of structures
  • Design guidance documents, codes and standards

Design of Welded Joints

  • Categories of welded joints
  • Design of welded joints with predominantly static loading
  • Design of welded joints with predominantly dynamic loading
  • Design against brittle fracture

Design of Welded Plate Structures

  • Plates and shells
  • Beam and column structures
  • Design considerations for welding residual stresses and distortion
  • Design for Purpose of Welded Structures

Introduction to Fatigue (included in variants: Design and Fatigue Intro, Complete Fatigue, Complete Course)

  • Materials considerations
  • Loading considerations
  • Stress-Life Based Fatigue, fatigue limit, factors influencing the S-N curve
  • Strain-Life Based Fatigue (cyclic plasticity, Neuber correction)
  • Processing of Load Records (rainflow, damage accummulation)
  • Failure probability and its influence
  • Factors Affecting Fatigue Life (various other issues that can be encountered)
  • Fracture Mechanics and Crack Propagation (Brief Treatment Only)
  • Multiaxial Fatigue
  • The Concept of FE Based Fatigue Analysis
  • Available Software Applications
  • Available Data Sources

Fatigue Analysis of Weldments (included in variants: Complete Fatigue, Complete Course, Barsoum)


  • Fatigue design of welded structures
  • History and failures, design philosophies
  • General advice regarding fatigue
  • Definitions of stress range, R-ratio, SN-curves, FAT classes and codes
  • Notches and stress concentration
    • Definition of local weld geometry
    • Stress concentration factors
    • Effect of local weld geometry on the fatigue life
  • Weld defects
    • Definition and classification
    • Effect on the fatigue life
  • Welding residual stresses
    • Formation and definition and characteristics
    • Effect on the fatigue life

Fatigue assessment methods according to IIW (International Institute of Welding)

  • Nominal stress
    • Definition of nominal stress
    • FAT-values and structural details
    • Limitations of nominal stress methods
    • Calculation examples: (1)Extrapolation of nominal stresses; (2) Two welded stiffeners attachment
    • Definition of weld throat stress
  • Geometric hot-spot stress method
    • Definition of structural stress
    • Application and limitations of method
    • Types of hot spots
    • FE modeling, stress evaluation and measurements
    • Fatigue resistance and FAT-values
    • Misalignment and distortion
    • Calculation Examples: (1) Fatigue resistance using reference details; (2) Fillet weld in longitudinal attachment; (3) I-Beam with long doubling plate
  • Effective notch stress method
    • Definition of notch stresses
    • Overview of different hypothesis, stress averaging approach by Neuber
    • Application and limitations
    • Fatigue resistance for different effective radii, FAT values
    • FE modeling and techniques for notches
    • Stress analysis using submodeling technique
    • Calculation Example: Comparison between nominal stress, notch stress and fatigue testing
  • Linear Elastic Fracture Mechanics (LEFM)
    • Definition of loaded cases and modes, stress intensity factors
    • Fatigue crack growth; Paris law, Forman equation, Kitagawa diagrams
    • Case study: Residual stress effect on fatigue of welded steel structures using LEFM – application on large diesel engine
    • Calculation example: T-joint structure with several welds; fatigue life assessment using nominal, hot-spot, effective notch stress and LEFM

Special aspects; Fatigue strength modification

  • Wall thickness
  • Elevated temperature
  • Mean stress

Fatigue assessment methods

  • General remarks
  • Design and manufacturing of welded structures
  • Range of application

Weld improvement techniques

  • How to increase the fatigue life
  • Improvement techniques overview
    • Weld geometry modification
    • Residual stress modification
  • Burr grinding
  • TIG dressing
  • Hammer peening, High frequency Mechanical Impact (HFMI)
  • Low Temperature Transformation fillers (LTT)
  • IIW recommendations and fatigue resistance

Variable amplitude loading

  • Spectrum loading
  • Rain flow counting, ASTM E1049
  • Cumulative damage, Palmgren-Miner, Modified Miner´s rule
  • Sequence effects, equivalent stresses
  • Load-Strength models, failure rate predictions
  • Residual stress relaxation and models

Weld Quality Systems

  • Bad weld quality – history and present time
  • Definition of weld quality and acceptance levels
  • Current weld quality systems
  • ISO 5817
  • Volvo STD
  • Design for purpose, weld requirements
  • Weld quality systems related to fatigue strength
  • "State-of the art": Digitalization of weld quality control and assurance for welded structures subjected to fatigue

Finite element modeling and fatigue analysis

  • Case studies: Fatigue life analysis and failure investigation
    • Volvo Articulated Hauler beam structure
    • Volvo Wheel loader welded link
    • Volvo AH Rear frame structure
    • Failure investigation in a Volvo excavator arm
  • Case studies: Fatigue life analysis and design
    • Welded RHS in mobile crane application
    • Laser welded automotive gear box shaft
    • Welded tumble dryer in pulp industry
    • Fatigue design of offshore structures

Latest in development in fatigue design of welded structures – HFMI

  • IIW recommendations and guidelines

FEM practice cases (and optional homeworks)

  • #1 Introduction to the effective notch stress method
  • #2 Fatigue life analysis of welded structure using fracture mechanics
  • #3 Fatigue life analysis of a 45-degree butt weld joint
  • #4 Welded joint design



Timetables of past volumes, last update: September 05, 2017

Czech Society for Mechanics

FME   CTU in Prague





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