PSI - Issue 52
Ruben I. Erives et al. / Procedia Structural Integrity 52 (2024) 600–610 Ruben Erives et al./ Structural Integrity Procedia 00 (2019) 000–000
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Fig. 8. Initiation parameters as a function of the phase angle (i.e., mixed mode) obtained from AE method (in blue) and deviation from linearity (in red).
4.4. Crack-tip localization The localization of the crack tip along the length of the specimen is obtained from the two AE sensors is shown as a function of elapsed time in Fig. 9 for: a) mixed-mode specimen and b) (near) pure shear opening displacement specimen. It can be observed that in both instances region I and region II can be identified. The region I of the specimen with large phase angle values (shear dominated) is much longer than that observed in specimens with low . In region I, the crack front (region with high density of localised events in grey circles) remains at its initial position (localisation of zero). In region II, the crack front stars advancing.
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a) b) Fig. 9. Localisation of the crack front as a function of time using a gradient blue scale to denote the value of the instantaneous energy. The plots are extracted for a) mixed-mode specimen, and b) (near) pure shear opening displacement. The vertical dash lines indicate the boundaries of region I and region II, while the thicker dash line indicates the crack front localisation.
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