Predicting fatigue transverse crack growth in cross-ply carbon–epoxy laminates from quasi static strength tests by using iso-damage curves
✍ Scribed by Nguyen The Hoang; Denys Gamby; Marie-Christine Lafarie-Frenot
- Book ID
- 103831509
- Publisher
- Elsevier Science
- Year
- 2010
- Tongue
- English
- Weight
- 818 KB
- Volume
- 32
- Category
- Article
- ISSN
- 0142-1123
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✦ Synopsis
Cross-ply laminates made of carbon/epoxy IM7/977-2 system are investigated. The fatigue study is confined to ambient temperature conditions and zero loading ratio. Damage is characterized by the transverse crack density q in the central 90°-layer. The family of experimental fatigue cracking curves (q versus N, where N is the number of cycles, for each tensile test maximum stress amplitude) can be replaced with a set of ''iso-damage curves", i.e. contour curves of constant q in the r-log (N) plane.
The iso-damage curves approximately constitute a fan of straight lines that intersect at a common point (r e , log (N s )), where N s is a very large number of cycles beyond which no more crack appears, and r e is some fatigue limit.
Our aim is to propose a simple method to predict fatigue cracking at an arbitrary maximum stress level loading by using data stemming from a constant strain rate test. This method essentially rests upon the construction of the above ''iso-damage" curves, using very simple assumptions.