PSI - Issue 21

Hakan Şahin et al. / Procedia Structural Integrity 21 (2019) 38–45 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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A view of a typical finite element model is given in Fig. 3, which includes an inclined crack (45 degree). Details of mesh near the crack region can also be seen in Fig. 3.

Fig. 3: FE mesh of a plate containing inclined semi-elliptical surface crack (a) global view; (b) close-up view of crack region.

3. Results The shown graphs in this section provide representative solutions for three different values of aspect ratio ( a/c ), in which a/t is 0.4. The aspect ratios (a/c) are, respectively, 0.25, 1.0 and 4.0. Mode-I SIFs are plotted in Fig. 4. It is seen from the figures that as the inclination angle β increases the values of mode-I SIFs decrease when a/t and a/c are constant. It is also observed that when a/c is smaller than 1.0, mode-I SIFs are higher at the depth point, whereas they are higher on the free surface for a/c =1.0 or higher. Fig. 5 shows the normalized mode-II SIFs along the inclined crack fronts. The highest values for the mode-II are obtained at 45 degrees (the plane with the maximum shear stress). It can be seen in Fig.5 that, mode-II SIFs are equal for the complementary inclination angles (15-75 and 30-60) as expected. In the normalized K 2 values, it is seen that there is an anti-symmetric distribution between θ = 0 ° -90 ° and 90 ° -180 ° for the same a/t values.

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