Adhesive joints are essential in modern engineering, offering lightweight, durable and efficient solutions for bonding in industries such as aerospace, automotive, and renewable energy. However, their fatigue performance under cyclic loading remains a critical challenge, shaped by a complex interplay of geometrical, material, environmental, and loading factors. This review explores the mechanisms of fatigue failure, highlighting the importance of joint design, material optimization, and surface preparation in mitigating stress concentrations and enhancing durability. Advances in toughened adhesives, surface treatments, and environmental protection methods are highlighted, along with predictive models ranging from empirical S-N curves to advanced finite element simulations and probabilistic approaches. Despite significant progress, challenges remain in integrating these techniques for real-world applications, particularly under variable loading and harsh environmental conditions. Future research must focus on hybrid methodologies, adaptive materials, and standardized protocols to bridge the gap between laboratory insights and practical implementations. This comprehensive review provides a foundation for improving the fatigue performance of adhesive joints, ensuring their reliability and effectiveness in critical engineering systems.

Reliable joining of dissimilar structural materials requires tailored surface engineering to ensure stable interfacial performance. This study investigates the influence of mechanical (grinding, sandblasting), chemical (etching), and femtosecond laser surface treatments on the adhesive bonding behavior of DP600 high-strength steel and carbon fiber-reinforced polymer (CFRP). Treatments were applied individually and in combination, and their effects on surface topography, surface energy, and lap-shear strength were evaluated. For DP600 steel, femtosecond laser processing caused only moderate changes in conventional roughness parameters but increased shear strength by up to 200% compared to the untreated condition, indicating that surface activation dominates over purely geometrical effects. In CFRP, laser irradiation significantly increased the developed surface area and enhanced shear strength by up to 185%. Although mechanical and chemical treatments improved adhesion, laser processing consistently provided additional strengthening, particularly through combined topographical and physicochemical modification. The results establish a clear relationship between surface processing and mechanical performance. Femtosecond laser treatment emerges as an effective and controllable surface-engineering approach for improving adhesive bonding in both metallic and composite substrates, with direct relevance to laser-assisted industrial joining technologies.