ENME

ENME 489J - Fatigue

3 Credits

Instructor 

Rahman, Dr. Anisur

Textbook 

Required Textbook: 
  • Julie A. Bannantine, Jess J. Comer, and James L. Handrock, Fundamentals of Metal Fatigue Analysis, Prentice Hall, Englewood-Cliffs, 1990, 237 pp., ISBN 0-13-340191-X
Reference Textbooks:
  • Norman E. Dowling, Mechanical Behavior of Materials (Engineering Methods for Deformation, Fracture and Fatigue), 4th Edition, Prentice-Hall, Englewood Cliff, 2013, 936 pp. ISBN-13:978-0-13-139506-0
  • T. L. Anderson, Fracture Mechanics (Fundamentals and Applications), CRC, Boca Raton, 1991.
  • David Broek, The Practical Use of Fracture Mechanics, Kluwer Academic Publishers, Boston, 1989.

Prerequisites 

ENES 220
ENME 271, MATH 206, ENME 202, or equivalent

Description 

Development and application of the three major methods to quantify fatigue damage in order to predict/specify service life and design fatigue resistant structures.

Goals 

  • Understand the basic formulations of the three empirically-based analytical fatigue life assessment methodologies
  • Develop basic engineering to apply the three analytical fatigue life assessment methodologies to rudimentary structural components
  • Recognize the pros and cons of each of the three fatigue life assessment methodologies
  • Formulate and apply basic numerical methods for fatigue estimation using MATLAB

Topics 

Fundamentals
  • Historical Perspective
  • Mechanics review
  • Strength Design vs. Fatigue Design
  • MATLAB review
Stress-Life Analysis & Design
  • High cycle versus low cycle
  • S-N curves
  • Nonzero mean stress & empirical curves
  • Stress concentration factor, Kt
  • State of stress at a stress concentration
  • Cumulative Damage
  • Variable Amplitude Loading
  • Notches

Strain-Life Analysis & Design

  • s-e relationship (nonlinear: Ramberg-Osgood)
  • Cyclic σ-ε relationship
  • Local σ-ε approach to initiation
  • Empirical cyclic σ-ε curve
  • Strain life curve
  • Notches
Fracture Mechanics
  • da/dN – ΔK
  • Geometry factor
  • R effects on crack growth
  • Life estimates for constant amplitude
  • Crack growth retardation
  • Stationary histories

Learning Outcomes 

  • an ability to apply knowledge of mathematics, science, and engineering
  • an ability to identify, formulate, and solve engineering problems
  • an ability to use the techniques, skills, and modern engineering tools necessary for engineering practice

Class/Laboratory Schedule