Analysis of Methods for Determining High Cycle Fatigue Strength of a Material With Investigation of Ti-6Al-4V Gigacycle Fatigue Behavior

Abstract

This research utilized the benefits of numerical simulation to investigate the staircase method for use in fatigue strength testing. The staircase method is a commonly used fatigue strength test, but its ability to characterize fatigue strength variability is extremely suspect. A modified staircase approach was developed and shown to significantly reduce bias and scatter in estimates for fatigue strength variance. Experimental validation of this proposed test strategy was accomplished using a dual-phase Ti-6Al-4V alloy. The HCF behavior of a second material with a very different microstructure (beta annealed Ti-6Al-4V) was also investigated. The random fatigue limit (RFL) model was investigated to characterize stress-life behavior. Two alternative models (bilinear and hyperbolic) were developed based on maximum likelihood methods to characterize the Ti-6Al-4V fatigue life behavior. Based on this research, designers should be better able to make reliable estimates of fatigue strength parameters using small-sample testing.

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Document Details

Document Type
Technical Report
Publication Date
Oct 01, 2005
Accession Number
ADA441887

Entities

People

  • Randall D. Pollak

Organizations

  • Air Force Institute of Technology

Tags

Communities of Interest

  • Ground and Sea Platforms

DTIC Thesaurus Topics

  • Computational Science
  • Crystal Lattices
  • Data Science
  • Failure Mode And Effect Analysis
  • Fatigue Tests (Mechanics)
  • Information Science
  • Materials
  • Materials Processing
  • Materials Science
  • Materials Testing
  • Maximum Likelihood Estimation
  • Mechanical Working
  • Mechanics
  • Statistical Analysis
  • Statistical Inference
  • Test And Evaluation
  • Test Methods

Fields of Study

  • Materials science

Readers

  • Regression Analysis.
  • Structural Health Monitoring of Composite Structures.