Efficient 3D analysis of composite laminates using high-aspect-ratio discontinuous Galerkin finite elements

Designing reliable composite structures often hinges on resolving ply-level and interlaminar stresses, which demands truly three-dimensional analysis of the laminate. However, conventional 3D finite element models based on low-aspect-ratio elements quickly become impractically large when thin plies must be resolved over wide in-plane spans. This work investigates a high-aspect-ratio discontinuous Galerkin finite element method (DG-FEM) as a framework for accurate, scalable laminate analysis. A 3D symmetric interior penalty formulation is used for orthotropic laminates on stretched hexahedral meshes, allowing refinement to be aligned with stress concentrations while keeping the mesh coarse at the structural scale, thereby enabling laminate models with far fewer elements and degrees of freedom compared to conventional approaches. The method is first verified on an isotropic cantilever beam and on manufactured solutions with isotropic and orthotropic interfaces, demonstrating the optimal convergence rate on elements with high aspect ratios. Classical cross-ply and angle-ply free-edge benchmarks are then used as stringent tests: the DG-FEM reproduces established interlaminar stress distributions with excellent agreement to hierarchical conforming FEM, with up to an order of magnitude fewer degrees of freedom in the cross-ply case. Together, these results indicate that high-aspect-ratio DG-FEM can deliver three-dimensional stress fields for laminated composites at substantially reduced computational cost, providing a strong basis for efficient 3D stress analysis in laminate studies. • High-aspect-ratio DG-FEM enables efficient 3D laminate stress analysis. • DG-FEM preserves optimal L 2 convergence up to aspect ratio ≈ 40 . • Accurately recovers free-edge interlaminar stresses. • Matches hierarchical FEM with about ten times fewer unknowns. • Supports coarse, stretched hex meshes focused on stress concentrations.