Abstract This study investigates the effects of various adhesive properties on the mechanical behavior and failure modes of steel-GFRP single-lap joint specimens through tensile shear tests conducted on 18 samples. The experimental results indicate that the interfacial failure modes of steel-GFRP joints are significantly influenced by adhesive stiffness. High-stiffness adhesives (JGD, Sika, FCSRS, PRUD, Tris) exhibited failure at the steel-adhesive interface, whereas the low-stiffness LD-308 adhesive demonstrated cohesive failure within the adhesive layer. By comparing the parameters of the materials themselves, it is evident that binders with a high tensile modulus tend to exhibit greater bonding stiffness. The ratio of interface strength to material tensile strength directly influences the failure mode. When these values are comparable, interface failure becomes the dominant form of failure. Conversely, when the material tensile strength significantly exceeds the interface strength, failure occurs within the adhesive layer, resulting in cohesive failure. Numerical models for six adhesive specimens were developed based on the cohesive zone model, Hashin damage theory, and experimental parameters. The calculation errors remained below 0.2 when compared to the test results, demonstrating good simulation accuracy. Using the Sika adhesive model, parametric studies were conducted on bond length, width, and steel substrate thickness. The results indicate that the ultimate bearing capacity exhibits an approximately linear positive correlation with bond length and width, while failure displacement correlates linearly with bond length. However, both parameters remain largely independent of the steel substrate thickness.
Guo et al. (Mon,) studied this question.