| Abstract [eng] |
Recently, composite materials have been increasingly used in aircraft structure design due to their favorable mechanical properties. These materials offer a high strength-to-weight ratio, which is crucial in aviation; however, lightweight structures are more sensitive to aeroelastic instabilities such as flutter and divergence. Flutter is defined as a dynamic unstable vibration response, while divergence is a structural instability caused by excessive aerodynamic loads. To effectively suppress these phenomena, it is important to conduct research on aeroelastic suppression systems. After analyzing the literature on aeroelastic phenomena and existing suppression systems, it was found that the most effective are active suppression systems, which can dynamically adapt to changing loads and environmental conditions. The literature review showed that while various aeroelastic suppression methods are being investigated, no system using an electromagnetically controlled auxiliary mini-flap has been identified. Therefore, this work focuses on designing a new system that utilizes electromagnetically actuated mini-flap technology to suppress aeroelastic effects. Initially, a 3D model of a hypothetical unmanned aerial vehicle wing was created, and its strength, stiffness, and natural vibration characteristics were analyzed. The strength analysis revealed that the minimum safety factor according to the Tsai-Wu criterion is 1.52. The main vibration frequencies as well as the wing section’s bending and torsional stiffness were determined. Then, using a quasi-static method and a more advanced K-method, aeroelastic models of the wing were developed to identify key instability points. Calculations showed that divergence occurs first at a speed of 47.5 m/s, while flutter occurs at 54.5 m/s. Next, aerodynamic analysis of the airfoil was performed using “XFLR5“ software, during which the main characteristics of the profile were determined. The analysis revealed that the maximum absolute value of the pitching moment is Cm = 0.033. Based on this, a mini-flap with a 14% chord length and a 5° deflection angle was selected, covering 50% of the wing span. Aeroelastic mathematical models for damping were adapted based on the mini-flap configuration. Using the mini-flap as a passive damping element, the divergence speed increased from 47.5 m/s to 51.85 m/s. Dynamic vibration damping was analyzed at 47.5 m/s. When the mini-flap damping was activated after 0.5 seconds, the torsional oscillations were fully suppressed within approximately 0.4 seconds, and vertical wing motion also stabilized after 0.4 seconds. Finally, a conceptual prototype of the mini-flap system was developed, actuated by two electromagnets. Its structure was designed in SolidWorks and manufactured using 3D printing technology and steel plates. The prototype is operated using an Arduino Mega R3 microcontroller. |
