PSI - Issue 57

Cristian Bagni et al. / Procedia Structural Integrity 57 (2024) 598–610 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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Fig. 9. Representative examples of normalised stiffness vs cycles plots for a lap shear (a) short life test and (b) mid/long life test.

Fig. 10. Preliminary (a) experimental load-life datapoints and (b) reverse-engineered SN datapoints.

4. Conclusions In this paper, a practical methodology for the fatigue life estimation of adhesively bonded joints was proposed along with FE modelling guidelines to recover the peel stresses, along the bond lines, that can be used as an input to perform fatigue analyses using the DesignLife standard SN Analysis Engine. The proposed methodology can be easily adopted by companies in the transportation industry, and it requires relatively limited changes to the typical FE modelling strategies used today, especially in the automotive industry. Furthermore, the FE models obtained following these guidelines are not computationally too onerous, have a good level of mesh insensitivity and do not require congruent meshes. The proposed FE modelling strategy was applied to model both lap shear and coach peel specimen geometries, using ANSYS software and a convergence study was also carried out. The results of the convergence study show that, the addition of the membrane shell elements, on the exposed faces of the solid elements modelling the adhesive, is a valid solution to recover the peel stresses from the solid elements with the advantage of making these stresses reasonably mesh insensitive. Finally, the process to derive bespoke fatigue parameters of the adhesive joints through physical testing was also described. It is recognised that the number of datapoints currently available is limited. However, further tests belonging to the same test programme are currently underway. Once the test programme is complete, the full set of