Course Catalogue.

After participating in this course, you will be able to:

• Understand the fatigue damage mechanisms and the different characteristics of materials/alloys
• Determine the parameters needed to calculate the fatigue life and select the most appropriate lifing method
• Determine the low cycle fatigue or the high cycle fatigue life
• Understand the characteristics of welded joints and the methods to improve their fatigue life
• Have a better understanding of the crack propagation lifing

Description
When the cyclic load is applied to a mechanical component, fatigue life has to be calculated to ensure the component meets the design objectives. It is essential to understand the lifing methodology and consider all factors affecting the fatigue capability to calculate fatigue life accurately. Factors affecting fatigue strength are classified into intrinsic (related to the material) and extrinsic (related to component geometry and operating environment). This course is focused on fatigue damage mechanisms, the behaviour of different materials/alloys, lifing method, the parameters needed to calculate the fatigue life, and the characteristics of welded joints as well as an introduction to fracture mechanics.

Course Outline

• Fatigue damage mechanisms
• Fatigue test
• Material behaviours: steels, alloys
• Methods to calculate fatigue life
• Welded joints characteristics
• Cumulative damage
• Fatigue at high temperatures
• Introduction to fracture mechanics
• Case studies

Who Should Attend

Mechanical and Structural Engineers • Consultants • Engineers in Training

Course Syllabus

Day 1

Fatigue damage mechanisms

• Introduction
• Cyclic load
• Fatigue damage mechanisms

Fatigue test

• Endurance limit (for high number of cycles more than 105, 106 cycles)
• Low cycle fatigue (low number of cycles)

Material behaviours are the characteristics of;

• Steels
• Nickel alloys
• Aluminum alloys

Methods to calculate the fatigue life

• Low cycle fatigue
• Stress and strain based lifing methods
• SN diagram (/, N)
• Mean stress effect
• Stress concentration factor
• Parameters affecting the fatigue life; loading condition, stress concentration, surface finish, environment ...)

Case study

• Estimating the fatigue life;
• based on hand-calculated stress (beam theories)
• using the finite element stress analysis results including; determining the stress concentration factor and the stress condition (compressive, tensile and multiaxial stress distribution)

Day 2

• High cycle fatigue
• Principal fatigue parameters
• Goodman Jonson method
• Other lifing methods including the ASM code for rotating shafts

Case study

• Estimating the fatigue life using hand-calculated stress
• Estimating the life using the finite element stress analysis results

Welded joints characteristics

• Welded joints fatigue behaviours
• Methods to improve the welded joint fatigue life

Cumulative damage

• Miner rule
• Rain Flow

Fatigue at high temperature

• Environment effect
• Creep fatigue interaction

Introduction to fracture mechanics

• Basics of fracture mechanics
• Fatigue crack propagation
• Paris regime
• Close to the critical stress intensity factor
• Stress concentration zone and short crack propagation