Ultralight trusses are ideal for innovative aero-structures due to their high stiffness-to-weight

ratio and favorable aeroelastic properties. Their design must account for mechanical constraints, inclu-

ding maximum stress and local buckling. This work formulates a volume minimization problem for 3D

structures under multiple load cases, stress, and topological buckling constraints. A two-step optimization

strategy is used : first, a relaxed problem is solved via Sequential Linear Programming to explore the de-

sign space ; second, the full nonlinear problem is refined using IPOPT to satisfy all mechanical constraints.

The method is applied to the 3D wingbox of the Common Research Model, considering different mate-

rials—aluminum, titanium, stainless steel, and pultruded CFRP—and the environmental impact in terms

of CO2eq is evaluated.