Global/local finite element analyses supporting the design of a ceramic matrix composite wing leading edge of a re-entry vehicle

The thermo-structural design of critical components for re-entry vehicles (e.g. nose and wing leading edge) requires the adoption of very detailed and complex finite element thermal and mechanical analyses. Indeed, since very high heat fluxes are expected during the atmospheric re-entry, Ceramic Matrix Composites (CMC) are usually employed because they can guarantee lightness, high damage tolerance, crack/fracture resistance, high tensile, bending and compression strength aside from high temperature stability (1900 °C) and excellent thermal shock resistance. However, such materials, characterized by a complex micro-structure, require demanding numerical tools involving very high computational costs. For this reason, embedded Global/Local and sub-modelling approaches need usually to be employed in order to obtain high level of accuracy, especially in the most critical areas of the components, with a significant saving of the computational cost. These efficient numerical tools allow to perform detailed numerical analyses even in a preliminary design phase where very coarse global models are usually adopted. In the present work, embedded Global/Local finite element models and sub-models are defined with the aim to improve the design of the Wing Leading Edge of an hypersonic vehicle. The aerodynamic heating, experienced along the re-entry trajectory of the CIRA Unmanned Space Vehicle FTB-X has been used as loading condition for the wing leading edge design. Local models have been defined at the interfaces between the internal and the external structure, where structural criticalities are expected, and the corresponding numerical results have been assessed and compared. Finite element commercial environments have been adopted for the numerical computations.