On the Experimental Determination of CTOD Based R-Curves
It is demonstrated that the British Standard BS 5762 for measuring the crack tip opening displacement (CTOD) can be modified such that the resulting CTOD is equal to the CTOD measured at the fatigue crack tip. The modifications consist of accounting for crack growth and adjustment of the rotation factor to the material under consideration. The results obtained on six different materials show that the rotation factor depends slightly on the material and is independent of specimen type, crack length, specimen thickness, and amount of crack growth.
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