PSI - Issue 83

Ritesh M. Patel et al. / Procedia Structural Integrity 83 (2026) 41–46

43

ଶோ் ∗ ቀ ோ ௔ , ோ ௌ , ௘ ቁ

loading. ൌ ௉ ೎ೝ

(4)

Fig. 1. Cracked semi-circular bend (SCB) specimen Lim IL et al. (1993), (1994) Finite element method is used to evaluate T - stress in relation to the constant ratio of 0.5 for a/R and S/R . Using the SIF and T -stress values derived from FEM analysis, the geometrical constants Y I , Y II , and T ∗ are computed using Eq. (2), (3), and (4) while taking into account a 1000 N diametral compressive load for various crack angles. Fracture parameters K I , K II , and T - stress are derived from fracture analysis of PLA in mixed mode conditions. Using Eq. (2), (3), and (4), Table 1. Displays the computed values of the geometry constants Y I , Y II , and T ∗ for 40 mm radius at various crack angles. A non-dimensional metric called the biaxiality ratio (β) has been developed Williams (1957) to normalize the T stress with respect to the stress intensity component. The biaxiality ratio for mixed mode loading can be written as follows in relation to the SCB specimen: ߚ ൌ் ∗ ට௒ ಺ మ ା௒ ಺಺ మ (5) Table 1. Geometrical constants for SCB specimen Crack Angle Y I Y II T * 0 о 2.140 0 -0.912 5 о 2.098 0.150 -0.8891 10 о 2.068 0.601 -0.494 15 о 1.875 0.815 0.014 20 о 1.630 1.056 0.651 25 о 1.341 1.212 1.016 30 о 1.122 1.305 1.281 35 о 0.849 1.278 1.451 40 о 0.334 1.211 1.691 43 о 0 1.128 1.829 3. FE analysis of SCB specimen Different fracture angles and constant crack length ratios a/R = 0.5 are taken into consideration for the SCB specimen analysis, together with the loading distance ratio of S/R = 0.5, where 2S is the distance between the bottom supports as shown in Fig.1. Finite element analyses are performed for the SCB specimen to provide a full range of mode mixities, from pure mode-I to pure mode-II at different crack inclination angles. It can be challenging to pre pare an appropriate crack in this material for large values of a typically ( α > 60 о ) .For this reason, almost all of the study's numerical results relate to α < 60 о . The analysis takes into account the semicircular specimen under three point bending with an edge crack of length (a) at a variable crack angle (α) . The crack developed at different angle with