Z-Beam Wingbox Bend-Twist Optimisation of an Aeroelastic High-Aspect-Ratio Wing

This work presents a feature-driven inverse-design method for preliminary optimisation of two-dimensional Z-beam wing-box layouts. Connected diagonal and transverse primitives are parameterised by spanwise section lengths and member widths, then converted to a continuous density field using signed-distance functions, filtering and projection. The density field is reduced to equivalent one-dimensional Timoshenko beam stiffness and mass properties, allowing Z-beam layouts to be matched to prescribed bend--twist and mass characteristics. The method is demonstrated on rectangular and physical wing-planform domains, including tapered sections, and assessed through studies of objective formulation, mesh resolution, Z-beam section count, beam element count and initial configuration. The results show that low matrix-matching errors can be achieved at computational cost suitable for preliminary design. However, the inverse problem is non-convex and sensitive to parameterisation, grid resolution and starting point. The approach is therefore positioned as a rapid preliminary-design tool for exploring Z-beam layouts and tailoring effective aeroelastic beam properties prior to higher-fidelity structural and aeroelastic validation.