PSI - Issue 66

G. Cricrì et al. / Procedia Structural Integrity 66 (2024) 282–286 Author name / Structural Integrity Procedia 00 (2025) 000–000

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the maximum shear stress c  were considered; two values, 0.5 and 1, for the stiffness ratio  and two values, 2.5 and 5 mm, of the upper adherend thickness 2 h were chosen. Furthermore, for each combination of previous parameters, a series of joints with bonded lengths L ranging between 10 mm and 1000 mm was built.

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P c [N]

P c [N]

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h 1 = 2.5 mm ‐  = 1  c = 60 MPa

h 1 = 5.0 mm ‐  = 1  c = 30 MPa

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P c [N]

P c [N]

h 1 = 2.5 mm ‐  = 0.5  c = 30 MPa

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h 1 = 1.25 mm ‐  = 0.5  c = 60 MPa

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Fig. 3 – Lap-joints failure loads as function of the adhered length (legend:  FE model; - theoretical model)

In the diagrams of fig. 3, the failure loads obtained by the FE models, are compared with the predictions. It may be seen that there is a good agreement between numerical and theoretical results for all the joint geometries analysed and the considered values of the critical shear stress. Also, a comparison between theoretical and numerical load-elongation curves has been carried-out, as depicted in fig. 4. In most of the examined cases, the theoretical curves are very close to the corresponding ones obtained from FE simulations. Only for shorter joints, the elongations are over-estimated by the proposed model and significant errors are consequently observed.

4. Discussion and Conclusions A simple analytical model, useful for preliminary design of unbalanced lap-joint has been built. It is based on a