University of Illinois Urbana-Champaign

Local stress strain approach to cumulative fatigue damage analysis final report

Morrow, JoDean; Martin, J. F.; Dowling, N. E.

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https://hdl.handle.net/2142/112109

Description

Title
Local stress strain approach to cumulative fatigue damage analysis final report
Author(s)
  • Morrow, JoDean
  • Martin, J. F.
  • Dowling, N. E.
Issue Date
1974-01
Keyword(s)
  • Local Stress-strain
  • Fatigue Damage
  • Cumulative Fatigue
  • Load Histories
Abstract
A cumulative fatigue damage procedure for estimating the fatigue crack initiation life of notched structural members subjected to known load histories is outlined. This procedure assumes that a knowledge of the local cyclic stress-strain response of the metal at the most severely strained region in a member is sufficient to predict when a crack will form there. Some of the steps in this procedure that are of current interest and which are especially applicable to a local stress-strain approach are discussed. Alternative, approximate and/or abbreviated steps in the cumulative fatigue damage procedure are given wherever possible. Limitations of the method and areas where research is needed are pointed out. Cumulative fatigue test results for smooth specimens, notched plates and built-up box beams are compared to life calculations made using the local stress-strain approach. Cyclic deformation and fracture properties, used in the analysis, were obtained from tests on a limited number of axially loaded unnotched specimens. These examples indicate that a cumulative fatigue damage analysis based on the local stress-strain approach employing a minimum amount of materials test data can be used to make reasonable life estimates for members similar to many practical structural members. While there appears to be no serious limitations on the complexity of load histories that can be analyzed, the fatigue analysis of parts with complex geometric form is presently impractical without direct measurements of critical strains in the part.
Publisher
Department of Theoretical and Applied Mechanics. College of Engineering. University of Illinois at Urbana-Champaign
Series/Report Name or Number
  • TAM R 379
  • 1974-6001
ISSN
0073-5264
Type of Resource
text
Language
eng
Permalink
http://hdl.handle.net/2142/112109
Sponsor(s)/Grant Number(s)
Aero Structures Department, Naval Air Development Center, Warminster, PA, Contract No. N00156-70-C-1256, 74/01
Copyright and License Information
Copyright 1974 Board of Trustees of the University of Illinois

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Technical Reports - Theoretical and Applied Mechanics (TAM) PRIMARY
TAM technical reports include manuscripts intended for publication, theses judged to have general interest, notes prepared for short courses, symposia compiled from outstanding undergraduate projects, and reports prepared for research-sponsoring agencies.