## 5 Wing Component Structure Design Optimization Process
### Topology Optimization (TO) of the Support Element's Structure  
The initial design of the wing support elements, including its leading-edge ribs, trailing edge ribs, stringers, and stiffeners for the optimized wing based on the TO method were designed. The support elements of both wing segments were designed as shear webs to be stabilized against buckling loading, bending loading, torsion loading, and vertical shear loading. Other loads besides the aerodynamic loads and inertial loads applied to the wings can be considered in the design process according to their shapes and structural masses. In addition, the payload, expressed by electronic devices or surveillance cameras, can be carried on the wings and/or on the fuselage. This extra equipment adds more weight, thus contributing to the existing bending, shear, and torsion loads of the wing.  
The shear web structure of wing components provides a reliable design by enabling them to carry loads on the wing in different directions. The support elements' structure for both segments of a VSMTW is shown in Figure 10.  
The current meshing and boundary conditions of support wing elements were similar to those of the spars and ribs. The layout of the support elements' structure of the wing, the geometry of the mesh model, and its boundary conditions were established based on parametric data obtained from the aerodynamic investigation, as listed in Table 3. Since the support elements' weight contributes significantly to the total weight of the wing, it is important to reduce it while maintaining the wing stiffness. The rigid meshes of the support elements for both segments were designed by applying the TO using uniform tetrahedrons with their element's sizes of 3 mm.  
The number of meshing elements and nodes differs for each component, depending on its dimensions. Figures 11 and 12 illustrate some support components' meshing and boundary conditions for a fixed wing and a moving wing, respectively. A volume constraint was applied to the entire support element and served as an opposing constraint in the optimization problem.  
Figure 10: Support elements for fixed and moving wings at their original positions.  
Figure 11: Examples of A—geometry, B—meshing and C—boundary condition for support elements (leading-edge rib 1, rib 2, and bottom support lamina between ribs 5 and 6). (**A-1**,**B-1**,**C-1**) Geometry for support elements and the designable and non-designable areas for a fixed wing; (**A-2**,**B-2**,**C-2**)-Support elements meshing; and (**A-3**,**B-3**,**C-3**) Boundary conditions of the Support elements).  
The attached area between wing components cannot change from its initial design. Therefore, the edges of the support element components and the loci binding to other wing components were considered as non-designable areas. Since there are various places where links must be made to connect the wing components, such as spars and ribs, these components were defined with fixed areas during the TO. They represent the bonding with other wing components, and thus they can be altered throughout the optimization.  
Figure 12: Examples of A—geometry, B—meshing and C—boundary conditions for support elements (leading-edge rib 1, trailing edge rib 2, and support stringer front). (**A-1,B-1,C-1**) Geometry for some support elements and the designable and non-designable areas for a moving wing; (**A-2,B-2,C-2**) support elements meshing; and (**A-3,B-3,C-3**) Boundary conditions of the support elements).