Fatigue Damage of AA2024 Fiber–Metal Laminates With Architected TPU Interlayers and Graphene‐Modified Interfaces

This study investigates the fatigue behavior of Aluminum 2024 fiber–metal laminates incorporating three‐dimensionally printed thermoplastic polyurethane core architectures and graphene‐modified adhesive interfaces. Three core geometries, namely, diagonal, diamond, and hexagonal patterns, were evaluated with graphene contents of 0, 1.0, and 1.5 wt.% under different cyclic stress ratios. Mechanical and fatigue results showed that graphene‐modified interfaces and architected elastomer cores significantly improved load transfer, energy dissipation, and cyclic damage resistance. Tensile strength increased from 387.02 to 493.34 MPa, whereas impact energy improved from 12.18 to 24.02 J. The diamond architecture with 1.5‐wt.% graphene exhibited superior fatigue resistance, sustaining approximately 260–270 MPa at one million cycles. Stiffness degradation and accumulated strain analyses confirmed delayed damage evolution, improved stiffness retention, and reduced cyclic deformation. Fractographic observations indicated fiber bridging, fibrillar pull‐out, crack deflection, and limited delamination as dominant fatigue resistance mechanisms.