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Time Schedule of the WCFA-DFW

Course Lecturer

 

WCFA'17-DFW

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.

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

The complete programme can be downloaded here as a pdf file.

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

Monday, November 13, 2017
8:50-9:00 Jan Papuga Welcome info
9:00-10:30 Zuheir Barsoum Welding Technology
Design of Welded Structures
10:30-11:00   Coffee break
11:00-12:30 Zuheir Barsoum Design of Welded Joints
12:30-13:30   Lunch
13:30-15:00 Zuheir Barsoum Design of Welded Joints
15:00-15:30   Coffee break
15:30-17:00 Zuheir Barsoum Design of Welded Plate Structures

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)

Tuesday, November 14, 2017
8:50-9:00 Jan Papuga Welcome info
9:00-9:45 Milan Růžička History of fatigue and fatigue estimation methods
Materials considerations
Loading considerations
9:45-10:30 Jan Papuga Stress-Life Based Fatigue, fatigue limit, factors influencing the S-N curve
10:30-11:00   Coffee break
11:00-12:30 Jan Papuga Factors Affecting Fatigue Life (various other issues that can be encountered)
Strain-Life Based Fatigue (cyclic plasticity, Neuber correction)
Processing of Load Records (rainflow, damage accummulation)
An example of the workflow
12:30-13:30   Lunch
13:30-15:00 Josef Jurenka Fracture Mechanics and Crack Propagation
15:00-15:30   Coffee break
15:30-17:00 Jan Papuga Multiaxial Fatigue
The Concept of FE Based Fatigue Analysis
Available Software Applications
Available Data Sources
19:00-...   Informal social meeting at the Vinohradský pivovar brewery

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

Wednesday, November 15, 2017
8:50-9:00 Jan Papuga Welcome info
9:00-10:30 Zuheir Barsoum Introduction
10:30-11:00   Coffee break
11:00-12:30 Zuheir Barsoum Introduction
12:30-13:30   Lunch
13:30-15:00 Zuheir Barsoum Fatigue assessment methods according to IIW (International Institute of Welding)
15:00-15:30   Coffee break
15:30-17:00 Zuheir Barsoum Fatigue assessment methods according to IIW (International Institute of Welding)
Special aspects; Fatigue strength modification
Thursday, November 16, 2017
8:00-9:30 Zuheir Barsoum Fatigue assessment methods
9:30-10:00   Coffee break
10:00-11:30 Zuheir Barsoum Weld improvement techniques
Variable amplitude loading
11:30-12:30   Lunch
12:30-14:00 Zuheir Barsoum Weld Quality Systems
Finite element modeling and fatigue analysis
14:00-14:30   Coffee break
14:30-16:00 Zuheir Barsoum Latest in development in fatigue design of welded structures – HFMI IIW recommendations and guidelines

Introduction

  • 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


papuga@pragtic.com, last update: September 30, 2017

Czech Society for Mechanics

FME   CTU in Prague

 

 

 

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