PSI - Issue 37

Jesús Toribio et al. / Procedia Structural Integrity 37 (2022) 1037–1042 Jesús Toribio / Procedia Structural Integrity 00 (2021) 000 – 000

1040

4

Fig. 2. Bolt geometry.

3.3. Stress intensity factor (SIF) computation In order to obtain the stress intensity factor along the crack line, the stiffness derivative method was used, based on the computation of the energy release rate upon a virtual crack extension (Astiz and Elices, 1980), cf. Fig. 3. In the matter of local crack advances of points located in the crack front in the plane of the crack (Fig. 4a), not only the main node p (shifted from p to p ') was displaced, but also the two adjacent nodes a in the crack front (shifted from a to a '). With such a system the cracked area increases in all its zones. This procedure avoids curving of the crack line and, therefore, a decrease in the cracked area (Fig. 4b).

Fig. 3. Virtual crack extension (VCE).

Fig. 4. Local crack advances in the plane of the crack: (a) without decrease in cracked area; (b) with decrease in cracked area.