PSI - Issue 39

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M.R.M. Aliha et al. / Procedia Structural Integrity 39 (2022) 393–402 Author name / Structural Integrity Procedia 00 (2021) 000–000

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Figure 4 presents the influence of different permutation of adherent materials on the fracture parameters of the analyzed BI-SBB specimen. It is seen that the location of adherent materials in the left and right side of the crack or adhesive, changes slightly the fracture parameters but among them the mode II stress intensity factor ( Y II ) is more sensitive to the change in the type of adherent materials. Under mixed I/II loading, fracture initiation occurs along a kinked direction relative to the original plane of crack. The direction of fracture initiation (θ 0 ), depends on the mode mixity and fraction of tensile/shear deformation. Variations of θ 0 for different crack inclination angles in the investigated BI-SBB samples have been shown in Figure 4 and Table 3. It is seen that this angle increases from zero (for pure mode I condition) to an angle of approximately 70 o (for pure mode II condition). Based on the Table 3, it can be concluded that the influences of adherent materials on the θ 0 are insignificant.

Fig. 4. The effect of Aluminium and Alumina adherent locations on the fracture parameters of the BI-SBB specimens with S/W = 0.6, a/W = 0.5. Table 3. Variations of fracture initiation angle ( θ 0 ) for mixed mode I/II loading for the BI-SBB specimen with S/W = 0.6, a/W = 0.5. crack inclination angle ( α ) Mode mixety permutation fracture initiation direction ( θ 0 ) 0° Pure mode I Al-Adhesive-Alumina 0 ° Alumina-Adhesive-Al 0 ° Al-Adhesive-Al 0 ° Alumina-Adhesive-Alumina 0 ° 30° Mixed mode I/II Al-Adhesive-Alumina -54.42 ° Alumina-Adhesive-Al -54.06 ° Al-Adhesive-Al -53.31 ° Alumina-Adhesive-Alumina -55.27 ° 40° Pure mode II Al-Adhesive-Alumina -70.23 ° 44.5° Alumina-Adhesive-Al -69.95 ° 44.5° Al-Adhesive-Al -70.16 ° 40° Alumina-Adhesive-Alumina -69.25 ° 4.1.1. Fracture path simulation using the incremental crack growth method (based on MTS criterion) Figure 5 shows the fracture path simulation for the BI- SBB specimen subjected to mixed mode I/II (α = 30°) loading using the incremental crack growth method (based on the MTS criterion). While for pure mode I the crack growth is stable and the propagation path is along the direction of the initial crack and inside the adhesive (i.e. cohesive fracture), for pure mode II and mixed-mode I/II, the crack propagation kink towards the adherent-adhesive interface.