Investigation of incremental fatigue crack growth mechanisms using in situ SEM testing

Wei Zhang, Yongming Liu

Research output: Contribution to journalArticle

59 Citations (Scopus)

Abstract

A novel in situ scanning electron microscope (SEM) fatigue testing is proposed in this paper to investigate the fatigue crack growth mechanisms within one cyclic loading under plane stress conditions. The objectives of the experimental study are to verify the hypotheses of a small time scale fatigue crack growth model and to develop a new experimental methodology for the detailed mechanism investigation of fatigue crack growth. During the testing, one loading cycle is uniformly divided into a certain number of steps. At each step, high resolution images are taken around the crack tip region. Imaging analysis is used to quantify the crack growth kinetics and crack tip deformation behavior at any time instant in a loading cycle. Crack closure phenomenon is directly observed during the crack growth process in the current investigation. It is also observed that crack growth is not uniformly distributed within a loading cycle and only happens during a small portion of the loading path. Multiple mechanisms exist within one cyclic loading, which is not able to be captured using the classical cycle-based approaches. A detailed discussion is given based on the current investigation to explain some well-known issues in the classical fatigue theory.

Original languageEnglish (US)
Pages (from-to)14-23
Number of pages10
JournalInternational Journal of Fatigue
Volume42
DOIs
StatePublished - Sep 2012
Externally publishedYes

Fingerprint

Fatigue Crack Growth
Scanning Electron Microscope
Fatigue crack propagation
Crack propagation
Crack Growth
Electron microscopes
Scanning
Cycle
Crack tips
Testing
Cyclic Loading
Crack Tip
Fatigue
Crack closure
Fatigue testing
Growth kinetics
Image resolution
Crack Closure
Plane Stress
Growth Process

Keywords

  • Crack closure
  • Crack growth
  • Fatigue
  • In situ
  • SEM

ASJC Scopus subject areas

  • Industrial and Manufacturing Engineering
  • Mechanical Engineering
  • Mechanics of Materials
  • Materials Science(all)
  • Modeling and Simulation

Cite this

Investigation of incremental fatigue crack growth mechanisms using in situ SEM testing. / Zhang, Wei; Liu, Yongming.

In: International Journal of Fatigue, Vol. 42, 09.2012, p. 14-23.

Research output: Contribution to journalArticle

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