PSI - Issue 42

Hasan Saeed et al. / Procedia Structural Integrity 42 (2022) 967–976 Hasan et al./ Structural Integrity Procedia 00 (2022) 000 – 000

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strain compliance data and DCPD Fig. 9.

Fig. 9 Comparison of crack length measurement (in terms of a/W) using back-face strain compliance data and DCPD The crack length to width ratio / from the proposed extended back-face strain compliance follows the crack length to width ratio / measurements obtained from DCPD technique. The DCPD technique depends on the empirically determined relationship between the measured potential and crack length. In crack propagation experiments, however, there are discrepancies between the crack lengths determined on the fracture surface and the potential drop measurement (Bär, 2020).

Fig. 10 Fracture surface of a beachmark test

This will be related to non-uniformity of the evolution of the crack front during the fatigue test, as seen in the fractography (refer Fig. 10). This will be addressed in future work by using multiple strain gauges along the width of the specimen (and identical distance to the notch) to better capture this non-uniformity in crack front evolution.