PSI - Issue 57

Cristian Bagni et al. / Procedia Structural Integrity 57 (2024) 859–871 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

870 12

Fig. 8. Example of failed specimens.

Fig. 9. Preliminary (a) experimental load-life datapoints and (b) reverse-engineered SN datapoints.

4. Conclusions In this paper, two practical methodologies for the fatigue life estimation of hybrid joints were proposed. The proposed methodologies can be easily adopted by companies in the transportation industry, and they require reasonably small changes to the typical FE modelling strategies used today, especially in the automotive industry. The first methodology is based on the conservative assumption that the life of the hybrid joint corresponds just to the life of the adhesive, neglecting the life given by the mechanical joints after failure of the adhesive. FE modelling guidelines are proposed to efficiently recover the peel stresses, along the bond-lines, that can be used as input to perform fatigue analyses using the DesignLife standard SN Analysis Engine. The FE models obtained following the suggested guidelines are not computationally too onerous, have a good level of mesh insensitivity and do not require congruent meshes. The second methodology extends the first methodology by considering the life of the hybrid joint as the sum of the life of both the adhesive and the mechanical joints. This methodology requires two separate analyses to estimate the fatigue life of the adhesive and of the mechanical joints, respectively. The fatigue life of the adhesive is estimated through the first methodology, while the fatigue life of the mechanical joints is estimated through a