Exploring the strength analysis of a double lap bi-adhesive joint using hybrid composite adherend and six-node pentahedron cohesive elements under different loading rates

In this study, the strength analysis of lap joint with a dissimilar composite laminate under different loading rates was investigated experimentally and numerically. In the experimental approach, two different double-lap joints were created. In the first part, lap joint was formed using two different composite adherends with a single type of adhesive. In the second part, another lap joint was made using two different composite adherends, applying two different types of adhesives. This investigation aims to evaluate the performance and efficacy of the joints under varying conditions. In both lap joints, plain woven aramid fiber rein-forced epoxy (AFRE), plain woven glass fiber reinforced epoxy (GFRE) laminates, and hybrid composite laminate (HAGFRE) were used as adherend. HAGFRE is formed by stacking consecutive arrangements of aramid and glass fabrics. Tensile tests were conducted using the universal testing device at loading rates of 1, 10, and 50 mm/min. In numerical analyses, the composite adherend was modeled using an orthotropic elastic material with a solid 8-node element, and a mixed-mode cohesive zone model was employed by using a nonlinear 6-node pentahedron cohesive element for the adhesive. In addition, crack propagation within the damaged lap joint and cohesive damage in the adhesive were examined as part of the numerical analysis. This study mainly examines how the strength of Double Lap Bi-Adhesive Joints (DLBJ) changes at various loading rates, utilizing both experimental and numerical methods. The findings indicate that the numerical model accurately predicts maximum strength values when compared to experimental data determined under different loading rates.