PSI - Issue 75

J. Filho et al. / Procedia Structural Integrity 75 (2025) 353–362 J.Filho, L. Wittevrongel, F. Pieron, P. Lava / Structural Integrity Procedia (2025)

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Fig. 1. Schematic illustration of the signal-locking principle present in MatchID.

Fig. 2. (a) Mesh used to impose an analytical full-field displacement based on the Williams’ series expansion under mixed-mode loading and (b) synthetically deformed image generated by the MatchID FEDEF module. 4. Stress intensity factors (SIFs) From the full-field displacements obtained by DIC, the stress intensity factors (SIFs) can be extracted by full-field fitting using high-order series expansion proposed by Williams (1957). This is a well-known approach widely used to estimate SIFs in the presence of linear elastic materials. It should be remembered that SIFs are often used to predict the stress state near the singularity zone (crack-tip) and is useful for providing a failure criterion for brittle materials. The series expansion is given by the following expressions 1 ( , ) = ∑ ( ( ) ( ) ( , ) − ( ) ( ) ( , )) + − ( − ) ∞ =1 and (1) 2 ( , ) = ∑ ( ( ) ( ) ( , ) − ( ) ( ) ( , )) + + ( − ) ∞ =1 , (2)