Cohesive Zone Modeling of Lap Shear Behavior of Different Metal Alloys and Glass-Fiber-Reinforced Thermoplastic Polyamide Hybrid Composites

There is an increasing tendency toward adhesively bonded hybrid structures including thermoplastic matrix composites and some metallic alloys. In this context, this study aims to investigate the mechanical properties of adhesively bonded single-lap joints (SLJ) both experimentally and numerically. Therefore, a series of lap shear tests and numerical analyses are conducted on 35% glass-fiber-reinforced polyamide, aluminum, titanium (Ti₆Al₄V), and stainless-steel (SS304) alloys hybrid bonded joints. For determination of the effect of design parameters on joint strength, SLJ tests are carried out on specimens with different thicknesses, composite sequences, and overlap lengths. Moreover, the adhesive and bonded specimen interface is modeled using cohesive zone modeling (CZM). After examination across three different hybrid materials, the CZM model yields largely similar results to the experimental tests. The highest similarity is achieved with SS304, with a difference of only 1.5% with 6.1 ± 0.05 MPa. Also, the lowest similarity can be seen with Ti₆Al₄V, with a difference of 15% with 5.4 ± 0.06 MPa. Additionally, it is observed that laser surface texturing after sandblasting provides higher shear strength than abrasive sanding and sandblasting by creating a lap shear strength of 14.7 ± 0.18 MPa.