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Journal of Materials Science

, Volume 19, Issue 2, pp 385–395 | Cite as

Fatigue-crack advance mechanisms in polymers

Part 2 Semicrystalline polymers forT<Tg (polybutylene terephthalate)
  • T. A. Morelli
  • M. T. Takemori
Papers

Abstract

The room-temperature fatigue-crack propagation behaviour of poly(butylene terephthalate) is strongly influenced by hysteretic heating near the crack tip since the glass transition temperature is just above room temperature. At low frequencies or stress intensities, the crack tip damage zone consists of several layers of crazes. At high frequencies or stress intensities, hysteretic heating causes a drop in yield stress and a large increase in the depth of the crack tip damage layer. At the same time, the increase in the plane stress plastic zones near the free surfaces produces large shear lips which flank the interior craze zone. This transformation results in a crack growth rate transition which appears as a crack deceleration followed by rapid crack acceleration. This thermal transition can be suppressed or delayed by immersion in water or silicone oil to reduce heat build-up in the sample during testing.

Keywords

Stress Intensity Glass Transition Temperature Crack Growth Rate Damage Zone Stress Plastic 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Chapman and Hall Ltd. 1984

Authors and Affiliations

  • T. A. Morelli
    • 1
  • M. T. Takemori
    • 1
  1. 1.Polymer Physics and Engineering Branch, Corporate Research and DevelopmentGeneral Electric CompanySchenectadyUSA

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