Fatigue Crack Propagation in Amorphous Poly(Ethylene Terephthalate).
Abstract
Earlier studies of fatigue crack propagation (FCP) in polymers have shown a general superiority of crystalline relative to amorphous polymers in terms of FCP resistance. In order to study in detail the effect of crystalline content and character on FCP rates, Poly(ethylene terephthalate) (PET) was selected as a convenient material in which a wide range of crystallinity can be obtained. In order to provide a base-line for comparison, FCP rates were determined for essentially amorphous polymers covering a range of molecular weight. Surprisingly, the essentially amorphous PET turned out to be as resistant to FCP as the best crystalline polymers so far observed. In this paper, several observations about FCP rates and fracture topography are reported: FCP rates agree well with the Paris equation over a wide range of delta K; in any case, the higher the molecular weight, the greater the crack growth resistance according with the Manson-Hertzberg relationship previously established. Fracture surface analysis revealed evidence of softening and drawing, and extensive plastic and shear deformation.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1982
- Accession Number
- ADA124143
Entities
People
- Alvaro Ramirez
- John A. Manson
- Richard W. Hertzberg
Organizations
- Lehigh University