An application of viscoelastic fracture criteria to steady crack propagation in a polymeric material under fixed deformation
✍ Scribed by R. Frassine; A. Pavan
- Publisher
- Springer Netherlands
- Year
- 1990
- Tongue
- English
- Weight
- 832 KB
- Volume
- 43
- Category
- Article
- ISSN
- 1573-2673
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✦ Synopsis
Tensile stress relaxation and stable crack growth under fixed tensile deformation over an extended range of crack speeds were measured on a flexible thermosetting epoxy resin. The experimental results are analysed and compared with the predictions of two theoretical models of fiacture kinetics in viscoelastic media, based on different approaches: one theory, developed by Schapery, postulates a criterion of material failure local to the crack tip; the second theory, evolved by Christensen, extends the overall statement of the conservation of energy to systems that dissipate energy due to viscoelastic effects. The observed behaviour is in qualitative agreement with the theoretical predictions. Quantitative discrepancies, however, call for further theoretical refinements. * Following the nomenclature proposal submitted by the Task Group on Polymers and Composites to the European Group on Fracture (EGF), we adopt here the subscript "c" to indicate the value of the stress intensity factor that exists in a given situation, which leads to crack extension. According to the same proposal, the critical stress intensity factor (leading to unstable crack propagation) is to be indicated by K~. c, instead.