In-Situ Optical Microscopy Study on Plastic Zone size estimation of aluminum alloy 7075-T6 under cyclic loading

Wei Zhang, Zizi Lu, Yongming Liu

Research output: Chapter in Book/Report/Conference proceedingChapter

Abstract

An in-situ optical microscopy fatigue testing is proposed in this paper to investigate the forward and reversed plastic zone under cyclic tensile loading. During the testing, every loading cycle is divided into a certain number of steps. Images of the crack tip are taken at each step. The full strain field around the crack tip is then determined using the digital image correlation (DIC) technique. The plastic zone size is obtained combining the DIC results and the material constitutive relationship. Experimental measurements are compared with theoretical predictions. It is observed that the crack closure effect has a large effect on the reversed plastic zone size. The plastic zone size remains almost constant when the unloading path is beyond a certain stress level. A modified model is proposed to estimate the crack tip plastic zone variation based on the experimental observations.

Original languageEnglish (US)
Title of host publicationFatigue of Materials: Advances and Emergences in Understanding
PublisherWiley Blackwell
Pages419-429
Number of pages11
ISBN (Print)9781118013373, 9780470943182
DOIs
StatePublished - Nov 11 2010
Externally publishedYes

Keywords

  • Fatigue
  • Image correlation
  • Optical microscopy
  • Plastic zone

ASJC Scopus subject areas

  • Engineering(all)
  • Materials Science(all)

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    Zhang, W., Lu, Z., & Liu, Y. (2010). In-Situ Optical Microscopy Study on Plastic Zone size estimation of aluminum alloy 7075-T6 under cyclic loading. In Fatigue of Materials: Advances and Emergences in Understanding (pp. 419-429). Wiley Blackwell. https://doi.org/10.1002/9781118013373.ch27