Variable-Angle Tow (VAT) laminates have gained increasing attention in the last decades, due to the improvement of mechanical properties achievable through the use of curvilinear fibres, when compared to the classic straight fibre format. These structures offer extended design possibilities, particularly in applications where lightness, stiffness and strength are crucial [1]. However, a major drawback of VAT structures lies in the increased numerical complexity that characterizes their analysis. The development of Carrera's Unified Formulation (CUF) within the context of Finite Element Method (FEM), allows to accurately predict VAT composites mechanical behavior, representing continuous in-plane fibres-path with an acceptable computational cost. However, the use of the Principle of Virtual Displacements (PVD) within this formulation does not allow to directly assess out-of-plane transverse stresses. This work aims to extend the application of CUF by implementing new families of hierarchical structural elements through Reissner's Mixed Variational Theorem (RMVT) [2]. RMVT allows to consider through-the-thickness stresses as primary simulation unknowns, improving the accuracy of the stress and displacement fields prediction within the structural domain. The main outcome of this method is in the development of more robust and accurate models for analyzing VATs mechanical response. REFERENCES: [1] Z. Gürdal, B. F. Tatting and C. K. Wu (2008). Variable stiffness composite panels: effects of stiffness variation on the in-plane and buckling response. Composites Part A: Applied Science and Manufacturing, Vol. 39, pp. 911-922. [2] D. A. Iannotta, G. Giunta and M. Montemurro (2024). A mechanical analysis of variable angle-tow composite plates through variable kinematics models based on Carrera’s unified formulation. Composite Structures, Vol. 327, pp. 117717.