Failure indices in ultra-thin deployable structures using 1D structural theories and 3D Hashin criteria

This work investigates failure indices in ultra-thin deployable structures in the context of nonlinear behavior. Deployable structures are increasingly critical in space engineering due to their ability to reduce mass, volume, and overall mission cost. Fabricated from thin or ultra-thin composite materials, these structures enable compact stowage and efficient deployment. Ultra-thin composites are prone to complex failure mechanisms influenced by stacking sequences and ply orientations. Identifying the onset of failure requires robust computational tools to limit the need for experimental testing, which is often costly and time-consuming. In this paper, the Carrera Unified Formulation is employed within a geometrically nonlinear framework. The full 3D stress field is evaluated at each equilibrium stage, and Hashin 3D failure indices are used to identify critical points along the nonlinear equilibrium path.