PSI - Issue 52

Ben M B Sargeant et al. / Procedia Structural Integrity 52 (2024) 472–479 Ben M B Sargeant , Catrin M Davies and Paul A Hooper / Structural Integrity Procedia 00 (2023) 151-158

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electrical current will be following the path of least resistance. Crack tunnelling in this sample cause the extreme edges to be considerably shorter than the crack front, only increasing by 0.33 mm. The sample edges present the path of least resistance, where the PD predicted crack growth likely originates as the growth of the extreme sides, plus a component of the shear surface contraction/tearing.

Fig. 3 Exemplar experimental crack potential difference (PD) data against machine load line displacement (LLD) during three-point-bending of a pre-cracked Charpy-sized SEN(B) sample. Initial linear trend identified as change in PD caused by strain and secondary linear trend identified as PD change by crack growth. The intersect of these points marks V 0 (83.3μV) as the beginning of crack growth.

Fig. 4 a) Comparison of measured crack length, with a linear fit, to ASTM and COMSOL models; b) Image of fracure surface with overlay showing precrack measurments area (yellow), Edge measurment lines (red) and middle crack measurment lines (green), with the same measurments repeated for for the test crack (blue)