Determination of critical CTOD using crack flank opening angle method in general yield regime

Abstract

The crack tip opening displacement (CTOD) evaluation from CMOD values using compact tension (CT) specimen geometry and plastic hinge model (PHM) is well standardized in the literature. However, the model is found to be conservative for the general yielding situation. Moreover, the knowledge of the location of apparent axis of rotation which in turn depends on plastic rotational factor, r pl , is essential for the conversion from CMOD to CTOD. In the present investigation, the 'crack flank opening angle' (CFOA) method has been suggested for the evaluation of plastic CTOD. This approach has facilitated the exact determination of apparent axis of rotation. The effect of the specimen thickness and notch root radius on CTOD has been investigated using the PHM and CFOA method. These results have been compared with finite element analysis results. Results achieved point out that the CTOD obtained from the traditional PHM are underestimated for the general yield situation.