A novel buckling design strategy for double-double (DD) laminates under in-plane shear loading has been developed, employing an off-the-shelf approach to enhance the applicability of DD configurations in aeronautical main structures. This strategy relies on four key components: Tsai’s modulus, the Master-Ply concept, the
maximization criterion, and a homogenization procedure tailored for commercially available unidirectional (0°, 90°) and angle-ply (±30°, ±45°, ±60°) carbon/epoxy prepregs. Finite element analysis (FEA) was used to validate analytical predictions for long/infinite composite plates under two primary boundary conditions: simply supported and clamped edges. From a design standpoint, increasing the number of sub-laminate repetitions [±ψ/±ϕ]rT effectively reduces bend-twist coupling effects
in DD laminates. Simultaneously, the bending stiffness components
increase by nearly an order of magnitude when the laminate thickness is doubled. Among the 13 DD configurations analyzed, those with smaller angles, such as [±0/±30]4 and [±0/±45]4, exhibit the lowest critical buckling loads under in-plane shear loading. However, configurations like [±0/±45]4 and [±30/±30]4 outperform the benchmark case [03/±452/90]s by 45.56% and 44.27%, respectively. A clear trend emerges: increasing the angle orientation reduces the half-wavelength of buckling, leading to higher critical loads. The top-performing DD configuration, [±60/±60]4, achieves a buckling load nearly double that of the benchmark case—an improvement of approximately 185%.
