A simple load-drop equation for estimating crack extension during fracture toughness tests
✍ Scribed by K.J. Karisallen; J. Morrison
- Publisher
- Elsevier Science
- Year
- 1994
- Tongue
- English
- Weight
- 553 KB
- Volume
- 47
- Category
- Article
- ISSN
- 0013-7944
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✦ Synopsis
Abstrac-Starting
from a generalized dimensional analysis, a relationship has been derived between post limit load crack extension and the corresponding decrease in applied load during a fracture toughness test using the discrete form of the calibration curve differential. Crack extensions from steel and aluminum compact and bend specimens, determined experimentally using both visual and unloading compliance techniques, were compared to those predicted from the load-drop equation. Good agreement was obtained between the predicted and experimental resuhs over a range exceeding 4 mm of crack extension. The predicted final crack lengths were in better agreement with a nine-point average measurement than were the unloading compliance results. NOMENCLATURE load-line force at i -1, i calibration (key curve) function load-drop function specimen width, length and thickness net specimen thickness crack length at time i remaining ligament at i -1, i plastic load line deflection linear elastic stress concentration factor stress intensity calibration factor elastic-plastic J-integral parameter plastic energy absorbed by the specimen Poisson's ratio Young's modulus plasticity correction factor plastic rotation factor