PSI - Issue 28

1616 M.Z. Sadeghi et al. / Procedia Structural Integrity 28 (2020) 1601–1620 M.Z. Sadeghi et al./ Structural Integrity Procedia 00 (2019) 000–000 Finite element analysis was carried out based on the data presented in Table 4. The Load displacement graphs for a bondline thickness of t a = 0.20 mm and 0.90 mm is as shown in Fig. 15 and Fig. 16. Based on the above graphs, both ECLM and J-integral give us a similar fracture load (P m ). However, the difference between the chosen data reduction scheme is evident during the post damage initiation of the material. Based on the comparison presented in Fig. 17, the fracture load P m results of 0.90 mm are over predicted. This is in contrast with our previous finding in (Sadeghi et al., 2020) where fracture toughness (G c ) values presented in (Campilho et al., 2013) for power-law index (  =  =1) was analysed. While under pure modes, P m is dependent on cohesive parameters (t n and t s ), in case of mixed-mode loading (such as SLJ), it is not clear whether the Damage initiation criteria or the Damage evolution criteria predict the onset of damage in Abaqus. Fracture toughness (G c ) influences the opening displacement in tension (  n ) and shear (  s ). This displacement in turn influences load distribution across the bondline based on the established CZM law (Campilho et al., 2012). In such a case, consideration of a trapezoidal CZM is one possibility that could reduce this error.

Fig. 15. Load-displacement curves of SLJ with bondline thickness 0.20 mm using (left) cohesive element method, (right) cohesive surface method.

Fig. 16. Load-displacement curves of SLJ with bondline thickness 0.90 mm (left) cohesive element method, (right) cohesive surface method.

Fig. 17. Fracture Load (P m ) comparison for bondline thickness (left) t a = 0.20 mm and (right) t a = 0.90 mm.