Multicriteria Optimization of Composite Wing of an Unmanned Aircraft

The article considers the results of multicriteria optimization of the unmanned aircraft composite wing. Minimum deflection, mass and normal stresses acting along the reinforcement directions are taken as optimization criteria. The thicknesses of the load-bearing frame elements and wing skin elements were selected as optimization parameters for three types of composites: carbon fiber reinforced plastic (CFRP) based on unidirectional carbon layers, CFRP based on carbon fabric layers, and fiberglass laminate based on E-glass fiberglass. A checking calculation of the optimal composite wing stability was performed using a geometrically nonlinear model. The calculation of the stress-strain state of the wing was performed using an anisotropic linear elastic material model. Calculations were carried out using finite element software packages ANSYS and FEMAP.

Modeling mechanical behavior of distributed piezoelectric actuators for morphing wing applications

PurposeA distributed piezoelectric actuator (DPA) improving the deformation performance of wing is proposed. As the power source of morphing wing, the factors affecting the driving performance of DPA were studied.Design/methodology/approachThe DPA is composed of a substrate beam and a certain number of piezoelectric patches pasted on its upper and lower ends. Utilizing the inverse piezoelectric effect of piezoelectric material, the DPA transfers displacement to the wing skin to change its shape. According to the finite element method and piezoelectric constitutive equation, the structure model of DPA was established, and its deformation behavior was analyzed. The accuracy of algorithm was verified by comparison with previous studies.FindingsThe results show that the arrangement way, length and thickness of piezoelectric patches, the substrate beam thickness and the applied voltage are the important factors to determine the driving performance of DPA.Research limitations/implicationsThis paper can provide theoretical basis and calculation method for the design and application of distributed piezoelectric actuator and morphing wing.Originality/valueA novel morphing wing drove by DPA is proposed to improve environmental adaptability of aircraft. As the power source achieving wing deformation, the DPA model is established by FEM. Then the factors affecting the driving performance are analyzed. The authors find the centrosymmetric arrangement way of piezoelectric patches is superior to the axisymmetric arrangement, and distribution center of the piezoelectric patches determines the driving performance.

Experimental Study of Rigid and Flexible Tandem Wing for Micro Aerial Vehicle

Unmanned aerial vehicle is becoming increasingly popular each year. Now, aeronautical researchers are focusing on size minimization of unmanned aerial vehicle, especially drone and micro aerial vehicle. The lift coefficient of micro aerial vehicle has wing dimension of 12 cm and mass of less than 7 g. In the present study, with the aid of 3D printer, polylactic acid material was used to develop the micro aerial vehicle structure for tandem wing arrangement. The materials for rigid wing skin and flexible wing skin were laminating film and latex membrane, respectively. The present work elaborates the lift coefficient profiles on rigid wing skin and flexible wing skin at wing flapping frequency of 11 Hz, three different Reynolds numbers of 14000, 19000 and 24000, and five different angles of attacks between 0° and 50°. According to the results obtained, the lift coefficient decreased as the Reynolds number increased. The lift coefficient increased up to 9 as the angle of attack increased from 0° to 50° at the Reynolds number of 14000 for flexible wing skin. The results also showed that the lift coefficient of flexible wing skin was higher than that of rigid wing skin at the attack angle of10° and below, except for the Reynolds number of 14000.

Conceptual Design Of A Modular Morphing Wing

In this dissertation a new modular design method for morphing wings is presented. First, a design method was created, applying modularity and recon gurability to a morphing wing system. With modularity being a requirement for the morphing wing system, a discretization method is developed to determine the discrete number of modules required to perform a desired morphing maneuver. Then, a specialized, modular, recon gurable variable geometry truss mechanism is proposed to facilitate morphing. The specialized modular wing truss is a recon gurable, limited mobility parallel mechanism, adapted to t within the volume of a wing. The mobility of the wing truss module is analyzed via a branch-based mobility and connectivity analysis that imposes kinematic requirements on the truss mechanism. The mobility and connectivity requirements are used to perform an enumeration analysis to isolate candidate module con gurations for morphing. Then, a parametric kinematic constraint system is developed and applied to the wing module and the kinematic performance of the module is evaluated. The kinematics are applied to a mechanical prototype of the wing module for validation purposes. Finally, the kinematics are used to evaluate the motion response of a wing skin system to lay the foundation for detailed design.

Conceptual Design Of A Modular Morphing Wing

In this dissertation a new modular design method for morphing wings is presented. First, a design method was created, applying modularity and recon gurability to a morphing wing system. With modularity being a requirement for the morphing wing system, a discretization method is developed to determine the discrete number of modules required to perform a desired morphing maneuver. Then, a specialized, modular, recon gurable variable geometry truss mechanism is proposed to facilitate morphing. The specialized modular wing truss is a recon gurable, limited mobility parallel mechanism, adapted to t within the volume of a wing. The mobility of the wing truss module is analyzed via a branch-based mobility and connectivity analysis that imposes kinematic requirements on the truss mechanism. The mobility and connectivity requirements are used to perform an enumeration analysis to isolate candidate module con gurations for morphing. Then, a parametric kinematic constraint system is developed and applied to the wing module and the kinematic performance of the module is evaluated. The kinematics are applied to a mechanical prototype of the wing module for validation purposes. Finally, the kinematics are used to evaluate the motion response of a wing skin system to lay the foundation for detailed design.

Development of dielectric elastomeric actuators for morphing wings

In the last decades, wing morphing structures have aroused great interest due to their capability to improve the aerodynamic efficiency of modern aircraft. DE actuators, also known as “artificial muscles” due to their ability to exhibit large actuation strains at high voltages, are suitable candidates for morphing applications. This paper focuses on the research and development of miniature dielectric elastomeric actuators for variable-thickness morphing wings. A conical elastomeric actuation configuration has been proposed, consisting of a VHB4910 dielectric membrane preloaded with a spring mechanism and constrained to a rigid circular ring. The mini-actuators are developed to be fixed in an actuation array, mounted to the wing skin. This new electromechanical actuation system is designed to be integrated on thin airfoil wings, where conventional morphing structures cannot be used, because of restricted mass and space requirements. By controlling the thickness distribution using the proposed actuators, we may be able to maintain and delay the location of the laminar-turbulent transit towards the trailing edge, promoting laminar flow over the wing surface. Experimental models and prototypes will be developed in the next phase of the research project for further investigations.

Technological features of autoclave molding of parts of complex configuration from В95оч alloy sheets

The development is shown with the use of modeling the technological process of autoclave molding, combined with the aging process, for the manufacture of upper wing skins from sheets of "В95оч" high-strength alloy taking into account the spring back of the workpiece. The results of studies of indicators of mechanical and corrosion properties of the resulting product are presented. Keywords: autoclave molding, heat treatment, springback, upper wing skin, sheet material, "В95оч". [email protected]

Optimization of shot peen forming patterns to achieve complex target shapes the inverse problem

The inverse problem of determining how to shot peen a plate such that it deforms into a desired target shape is a challenge in the peen forming industry. While peening thick plates uniformly on one side results in a spherical shape, with the same curvature in all directions, complex peening patterns are required to form other shapes, such as cylinders and saddles found on fuselages and wing skin panels. In this study, we present an optimization procedure to automatically compute shot peening patterns. This procedure relies on an idealized model of the peen forming process, where the effect of the treatment is modeled by in-plane expansion of the peened areas, and on an off-the-shelf optimization algorithm. For validation purposes, we peen formed three 305 X 305 X 4.9 mm and two 762 X 762 X 4.9mm 2024--T3 aluminium alloy plates into cylindrical and saddle shapes using the same peening treatment. The obtained shapes qualitatively match simulations. For 305 X 305 X 4.9mm plates, the relative differences had the same distribution and were of the same order of magnitude as initial out-of-plane deviations measured on the as-received plates.

Parametric Optimization of Load Bearing Elements for Composite Wing of an Unmanned Aerial Vehicle

This paper describes the optimizing results of structural elements of the composite wing of an unmanned aerial vehicle. The thickness and composite lay-up structure of load-bearing elements and wing skin are determined using the ANSYS software package. The optimal structure is presented using the Pareto set method of the “ideal center” basing on four criteria: minimum mass, deflection, normal stress, and maximum safety factor of the wing. Verification calculations were carried out to determine the safety factor of the load-bearing wing structure using a geometrically nonlinear model in FEMAP software.