Crack growth and fracture characteristics of riveted dissimilar aluminum joints under mode I loading

Crack initiation and propagation in aerospace structures can compromise structural integrity and service safety, making fracture assessment an important aspect of joint design. Riveted aluminum joints are widely used in engineering structures; therefore, understanding their crack-growth behavior under different loading conditions is of practical interest. In this study, the Mode I fracture behavior of riveted dissimilar aluminum joints was investigated using AL2024-T3 as the base material combined with AL2024-T0, commercially pure AL1100, AL5052-H3, and AL7075-T6 sheets. All specimens were fabricated with identical geometries and tested under displacement-controlled tensile loading. Force-displacement responses and crack-growth histories were recorded and correlated with the observed fracture behavior. Fracture performance was further evaluated using the stress intensity factor (SIF) and strain energy release rate (SERR) together with the geometric correction factor for side-cracked tension specimens. The experimental results indicate that alloy combination, sheet thickness, and local joint configuration influenced crack-growth behavior and fracture response. Among the tested configurations, the AL2024-T3 + AL1100 joint exhibited a longer crack-growth delay and more gradual fracture evolution, whereas the AL2024-T3 + AL7075-T6 joint developed the highest SIF and SERR values together with a rapid post-peak fracture response. In contrast, the AL2024-T3 + AL5052-H3 specimen failed in the riveted region before significant propagation of the predefined crack, preventing a meaningful fracture-mechanics evaluation. These findings improve the understanding of fracture behavior in mechanically fastened dissimilar aluminum joints and provide experimental data that may support the assessment and design of lightweight riveted structures.