# Design and Optimization of a Compliant Morphing Trailing Edge for High-Lift Generation
## 3 The Proposed Architecture
The design allows easier access to the narrow space and a more efficient replacement of the damaged parts. The idea at the basis of configuration C\({}_{3}\) is to produce a bending down of the skin, pulling the bottom edge by means of linear actuators. From a structural point of view, the forward edge of the top skin is clamped to the wing box interface, while the corresponding forward edge of the bottom skin is directly connected to the actuation kinematic chain. This assembly drives the forward movement of the bottom skin through dedicated tracks and, at the same time, represents itself as a structural constraint. The web contributes to the absorption of the loads--particularly shear loads--practically splitting the structure in two cells. The layout assures that a smooth deflection through the most critical part from the aerodynamic point of view--the upper skin--is bent down without any geometric discontinuity; the lower skin is deflected without any instability risk, as no shortening is required but instead just sliding the forward portion. Moreover, even if the slide zone is in principle a discontinuity region, its location from an aerodynamic point of view is less critical, and technical solutions (elastomeric sealing, f.i.) can be considered to further mitigate the problem. A ball-screw actuator for the operation of the morphing trailing edge was identified. Combined with a linear guidance system and mechanical transmission, this technology offers a complete solution for managing movement and synchronization in demanding environments while ensuring optimal control of aerodynamic surfaces. This actuation architecture identified by Collins Aerospace France and U.K. can be centralized or distributed. It is inherently irreversible or prone to the use of active power-off brakes. The ball-screw actuator system proposed by Collins Aerospace is based on a screw-nut mechanism, where a rotary movement (provided by an electric motor) is transformed into a linear movement. The linear guide maintains the path parallel to the lower surface, preventing any misalignment when activating the system. The mechanical transmission connected to the actuators synchronizes the movements of all the aerodynamic surfaces whether they are inboard, outboard, or located on either side of the blade. The combination of these technologies allows for quick adjustments, adapting to the conditions of use of the high-lift morphing trailing edges. This prevents any unintentional movement of the mechanism in the event of a mechanical failure. Moreover, the transmission ensures that all the movable parts maintain their relative positions, with no misalignment between them. The synchronization of movements reduces asymmetric effects, minimizing the risk of structural deformations. Aerospace environments impose severe stresses, such as temperature variations, continuous vibrations, and wing box deflection and prolonged exposure to dynamic loads. The ball-screw system, linear guidance, and mechanical transmission meet these challenges with a robust design that can withstand these high mechanical loads. The mechanical transmission ensures perfect coordination of the movable parts, even under extreme conditions. This solution also allows for a reduction in overall weight, as it is intrinsically lighter than hydraulic alternatives. Despite the above-mentioned advantages, some critical aspects must be discussed. First is the stress accumulation due to the compliant nature of the system [46], to which some regions seem particularly critical, such as the clamp of the upper skin, the web connections, and the sliding region on the lower skin. An accurate design must accomplish the stress mitigation task for these parts to assure an adequate safety and fatigue life. Another crucial aspect is represented by the actuators; since, in this specific layout, the actuation must cooperate with the structure in absorbing loads, any fault would have a potential impact not only in terms of functionality but also in terms of structural integrity.