Wing Folding Research Articles

Design and Mechanical Analysis of Bionic Foldable Beetle Wings.

In order to improve the flight performance of collapsible aircrafts, a novel mechanism of bionic foldable wings of beetle is designed based on the four-plate mechanism theory. The folding and unfolding movements of the bionic foldable wings are driven by motor and torsion hinges. Based on the D-H method, a kinematic model of wings is established to analyze the dihedral angle of adjacent plates. The folding ratio of an area in different plate creasing angles has been derived and calculated. Utilizing the kinematic and static models produced, as well as considering the folding ratio and output motor torque, the optimal physical parameters of folding wings are obtained. Dynamic models of rigid and flexible wings were established using ADAMS, and a motion simulation was performed. The relationship between dihedral angle and torque during the folding process of both rigid and flexible wings was obtained. The results provide a better understanding of the folding mechanism through the formulation of rigid-flexible wing analysis, as well as demonstrating a novel design of insect-mimicking artificial wings for small aerial vehicles.

Analysis of modularity and integration suggests evolution of dragonfly wing venation mainly in response to functional demands.

Insect wings show a high variability in wing venation. Selection for function, developmental pathways and phylogeny likely influenced wing vein diversification, however, quantitative data to estimate these influences and their interplay are missing. Here, it is tested how dragonfly wing vein configuration is influenced by functional demands, development, phylogeny and allometry using the concepts of modularity and integration. In an evolutionary context, modules are sets of characters that evolve in relative independence to other characters, while integration refers to a high degree of association between subparts of a structure. Results show allometric and phylogenetic signal in the wing shape variation, however, patterns of integration and modularity are not influenced by these two factors. Overall, dragonfly wings are highly integrated structures with almost no modular signal. Configuration changes in one wing vein or wing area thus influence wing shape as a whole. Moreover, the fore- and hindwings correlate with each other in their evolutionary shape variation supporting biomechanical data of wing interdependence. Despite the overall high degree of evolutionary integration, functional hypotheses of modularity could be confirmed for two wing areas, the arculus–triangle complex at the base of the wing which is responsible for passive wing folding especially during flapping flight and the location of the pterostigma, a coloured wing cell which is more heavy that other wing cells and passively regulates wing pitch as well as critical flight speeds during gliding. Although evolving as distinct modules, these specific vein regions also show high integration and evolve at the same rates like the whole wing which suggests an influence of these structures on the shape evolution of the rest of the wing. Their biomechanical role as passive regulators of wing corrugation and wing pitch suggests that these structures decisively influenced the evolution of advanced modern flight styles and explains their retention once they had evolved early within the lineage Odonatoptera.

Structure and evolution of the stigmapophysis—A unique repose wing-coupling structure in Psocodea

The gain of foldable wings is regarded as one of the key innovations enabling the present-day diversity of neopteran insects. Wing folding allows compact housing of the wings and shields the insect body from damage. Wing-fixing systems have evolved in some insects, probably to increase the durability of the shielding function by the wings. Bark lice (Psocodea) are known to possess a unique wing-to-wing repose coupling system, but a detailed morphological and evolutionary study of this system is lacking. In this study, we examined this repose coupling structure by SEM in 32 species including representatives of all three suborders of bark lice (Trogiomorpha, Troctomorpha and Psocomorpha). We concluded that the repose wing-coupling apparatus independently evolved twice within Psocodea. In Trogiomorpha, the apparatus is located on the subcostal vein of the forewing and is composed of elongated rib-like structures. In Troctomorpha and Psocomorpha, in contrast, the repose coupling structure is located on the radius vein of the forewing and is formed by a swollen vein. These morphological and developmental differences in the repose coupling structures also provide phylogenetic information at different systematic levels.

FAA Sets Rules for Boeing's Folding Wings

FAA Sets Rules for Boeing's Folding Wings

Stability Study of the Accident of a General Aviation Aircraft

In April 2014 an aircraft accident occurred at Jämijärvi aerodrome when a Comp Air 8 aircraft crashed into the woods. According to the scenario of the investigation report, the pilot reduced the engine power in such a way that the thrust became negative. Simultaneously the prop-washed kinetic pressure of the tail was reduced, which rapidly evoked a nose-down moment and a corresponding angular velocity. This led to a negative angle of attack and a large negative wing load and finally resulted in a wing strut buckling and the wing folding toward the aircraft’s body. In this study, six degree-of-freedom (6-dof) simulations are carried out for the aircraft to assess the supposed accident scenario. The simulations show that the proposed mechanism is possible, but there existed other potential courses of events after the thrust adjustment.

DESIGN AND CONTROL SYSTEM OF THE ROBOT ORNITHOPTER, EQUIPPED WITH WINGS AND TAIL

The paper deals with the ornithopter flight which simulates the flight of a bird. The robot consists of a body, two folding wings and a tail. The ornithopter roll is provided by wing swings, and pitch and yaw are provided by twists of the tail in two planes. When switching to the design scheme of the device, each wing is replaced by two links connected to each other and to the body by means of cylindrical hinges, the axes of all hinges are parallel to the longitudinal axis of the robot. Two mechanisms are used to implement swings in the device. One of them (the mechanism of swings) directly provides fluctuations in the wings relative to the body, as well as changing their area by adding when moving up and decomposition when moving down. This mechanism consists of a motor and crank-rod-rocker mechanism. The second mechanism (rotation of the ailerons on the wings) allows the wings in addition to flapping additionally to flex during motion, thereby "pocketing" of the air and the extra control area of the wings: its decrease with the movement of the wings up and the increase in the movement of the wings down. The tail is connected to the body due to the spherical hinge and two crank mechanisms. With the help of one of the mechanisms the tail rotates relative to the longitudinal axis of the body in the horizontal plane, and with the help of the other - in the vertical. For this robot a flight control system is proposed, which provides the robot movement along a given trajectory. The control system includes a control unit and a control device (ornithopter). The control unit is formed by modules specifying the effects and calculation of angles, as well as comparator and controller. The control device includes drives, links (wings and tail) and the robot body. Management is carried out on six generalized coordinates determining the position and orientation of the hull in space. For this purpose, eight feedbacks are used in the angles of rotation of the wings and the tail of the robot relative to its body.

Aerodynamic Characteristics of Tube-Launched Tandem Wing Unmanned Aerial Vehicle

Tube Launched UAV with expandable tandem-wing configuration becomes one of the most interesting topic to be investigated. Folding wing mechanism is used due to the requirements that the UAV should be folded into tubular launcher. This paper focuses on investigating the aerodynamics characteristics because of the effects of folding wing mechanism, tandem wing configuration, and rapid deploying process from tube launcher. The aerodynamic characteristics investigation is conducted using computational fluid dynamics (CFD) at low Reynolds numbers (Re < 200000). The results of the simulation are used for the development of ITB Tube-launched UAV prototype and for future studies.

Design of a hydraulically-driven bionic folding wing.

Membranous hind wings of the beetles can be folded under the elytra when they are at rest, and rotate and lift the elytra up only when they need to fly. This characteristic provides excellent flying capability and good environment adaptability. Inspired by the beetles, the new type of the bionic folding wing for the flapping wing Micro Air Vehicle (MAV) was designed. This flapping wing can be unfolded to get a sufficient lift in flight, and can be folded off flight to reduce the wing area and risk of the wing damage. The relationship between the internal pressures of the hydraulic system for the bionic wing folding varies and temperature was analyzed, the results show that the pressure within the system tends to increase with temperature, which proves the feasibility of the schematic design in theory. Stress analysis of the bionic wing was conducted, it was shown that stress distributions and deformation of the bionic wing under the positive and negative side loading are basically the same, which demonstrates that the strength of the bionic folding wing meets the requirements and further proves the feasibility of the schematic design.

BALOK PELAT BERDINDING PENUH (GIRDER PLATE BEAM)

Steel construction work generally requires a maximum power that can be retained by a cross-section of the burden, so for that we need a large enough cross-section to carry the load. In an attempt to overcome this problem, created a new profile as needed, so that the use of a cross-section Walled Beams Plates Plates Full or often called Girder (Girder Plate). Fully walled plate girder is a beam with a high cross-section, so it is probably influenced by the folding wings on plate element or the element plates bend the body, so that the necessary calculations to solve the folding and buckling. To overcome this happens folding or bending, buckling calculations required lokak (local buckling) and if it is necessary, then the component mounted stiffeners (stiffener), Bearing stiffener, Intermediate stiffener, and Longitudinal stiffener. To meet the needs of the beams to support the existing load, so he found a full-walled beam size plate (Plate Girder) d = 1,400 mm high, with a weight plate size 15 mm x 1350 mm, and the wing plate size 25 mm x 500 mm of steel fy = 240 MPa. Beam stiffeners fitted pedestal (Bearing stiffener), stiffeners between (Intermediate stiffener) and longitudinal stiffeners (stiffener Longotudinal).Keywords: girder plate, local buckling, stiffener

Analysis of Asymmetric Control Efficiency for Folding Wing Morphing Aircraft

Analysis of Asymmetric Control Efficiency for Folding Wing Morphing Aircraft

Parametric aeroelastic modeling based on component modal synthesis and stability analysis for horizontally folding wing with hinge joints

To investigate the aeroelastic stability of a folding wing effectively, a parametric aeroelastic analysis approach is proposed. First, the fixed interface component modal synthesis is used to derive the structural dynamic equation for a folding wing, in which the elastic connection is considered. The unsteady aerodynamic model is established by the doublet lattice method (DLM), and the aeroelastic model is achieved from integration of the DLM with the component modal analysis. The generalized aerodynamic influence coefficient matrix is established by modes kept and constraint modes of each component. The aeroelastic stability of a folding wing is investigated based on the Gram matrix in control theory. The effectiveness of the proposed method is verified via comparison with traditional flutter eigenvalue analysis for both extended and folded configurations. The proposed method identifies coupled modes and improves computational efficiency when compared to classical aeroelastic stability analysis methods, such as the p–k method.

Folding Wing Flight Test

While the concept of a laminar flow wing is well-known, the need to mechanise flaps and control surfaces makes this an impossible reality. Unless, of course, you use a Shape Memory Alloy.

Morphology of the elytral base sclerites

The elytral base sclerites (= sclerites located at the articular region between the forewing and thorax in Coleoptera) of selected taxa were examined and homologized. Although the elytral base sclerites are highly modified compared to the wing base sclerites of the other neopterans, they can be homologized by using the conservative wing flapping and folding lines as landmarks. A reduction of the first axillary sclerite was identified as a general trend of the elytral base sclerites, although the sclerite usually has a very important function to mediate flight power from the notum to the wing. This result indicates that the functional constraint against the basal sclerites is relaxed because of the lack of an ability to produce flight power by elytra. In contrast, the elytral folding system formed by the basal sclerites is well retained, which probably occurs because proper wing folding is a key for the shelter function of the elytra. The elytral base sclerites apparently contain more homoplasies than the serially homologous hindwing base sclerites of Coleoptera, which suggests that the structure is less useful for higher-level systematics. However, the faster evolutionary rate of the elytral base sclerites suggests there is potential for studying the lower-level phylogeny of Coleoptera.

Shape Memory Alloy Enables Folding Wings in Flight

Abstract The Spanwise Adaptive Wing project intends to obtain a wide spectrum of aerodynamic benefits in flight by folding wings through the use of an innovative and lightweight shape memory alloy.

Slow viscoelastic response of resilin.

The high importance of resilin in invertebrate biomechanics is widely known. It is generally assumed to be an almost perfect elastomer in different tissues. Whereas mechanical properties of resilin were previously determined mainly in tension, here we aimed at studying its mechanical properties in compression. Microindentation of resilin from the wing hinge of Locusta migratoria revealed the clear viscoelastic response of resilin: about a quarter of the mechanical response was assigned to a viscous component in our experiments. Mechanical properties were characterized using a generalized Maxwell model with two characteristic time constants, poroelasticity theory, and alternatively using a 1D model with just one characteristic time constant. Slow viscous responses with 1.7 and 16s characteristic times were observed during indentation. These results demonstrate that the locust flight system is adapted to both fast and slow mechanical processes. The fast highly elastic process is related to the flight function and the slow viscoelastic process may be related to the wing folding.

Ascending flight and decelerating vertical glides in Anna's hummingbirds.

Hummingbirds are observationally well known for their capacity to vertically ascend whilst hovering, but the underlying mechanics and possible energetic limits to ascent rates are unclear. Decelerations during vertical ascent to a fixed target may also be associated with specific visual responses to regulate the body's trajectory. Here, we studied climbing flight and subsequent deceleration in male Anna's hummingbirds (Calypte anna) over an approximately 2m vertical distance. Birds reached vertical speeds and accelerations up to ∼4 ms-1 and 10 m s-2, respectively, through the use of flapping frequencies as high as 56 Hz and stroke amplitudes slightly greater than 180deg. Total mass-specific power at maximal ascent speed was up to 92Wkg-1 body mass. Near the end of the ascending trajectory, all individuals decelerated ballistically via cessation of flapping and folding of wings over the body without losing control, a behavior termed here a vertical glide. Visual modulation of the deceleration trajectory during ascent was indicated by a constant value (∼0.75) for the first derivative of the time-to-contact to target. Our results indicate that hummingbirds in rapid vertical ascent expended near-maximal power output during flight, but also tightly controlled their subsequent deceleration during the vertical glide.

Is there a relationship between the morphology of the forewing axillary sclerites and the way the wing folds in aphids (Aphidomorpha, Sternorrhyncha, Hemiptera)?

The present study describes the relationship between the morphology of the forewing axillary sclerites and the way the wings fold among 24 aphid genera as compared to a representative of coccids. Architecture of the forewing base was imaged with scanning electron and optical (fluorescence) microscopy. Significant differences in morphology of axillary sclerites between aphid species were observed, despite their belonging to one infraorder. Detailed description of 41 features of axillary sclerites was made. There was no difference between axillaries of viviparous (Aphididae) and oviparous (Adelges sp., Phylloxera sp.) species. No clear relationship between morphology of the axillary sclerites and the wing folding could be confirmed. Instead, the thorax structure determines the way the wing folds in aphids. Phylogenetic analysis based on our results cannot be conducted at this stage of study. To show how three-dimensional the structures are and how difficult to describe, a short animation of Aphis fabae (Aphididae) wing base was added. This is a preliminary study about morphology of axillary sclerites among aphids.

Deployable wing model considering structural flexibility and aerodynamic unsteadiness for deployment system design

In future, wings will be deployed in the span direction during flight. The deployment system improves flight ability and saves storage space in the airplane. For the safe design of the wing, the deployment motion needs to be simulated. In the simulation, the structural flexibility and aerodynamic unsteadiness should be considered because they may lead to undesirable phenomena such as a residual vibration after the deployment or a flutter during the deployment. In this study, the deployment motion is simulated in the time domain by using a nonlinear folding wing model based on multibody dynamics, absolute nodal coordinate formulation, and two-dimensional aerodynamics with strip theory. We investigate the effect of the structural flexibility and aerodynamic unsteadiness on the time-domain deployment simulation.

Dusky works upstream of Four-jointed and Forked in wing morphogenesis in Tribolium castaneum.

Dusky (dy) is required for cytoskeletal reorganization during wing morphogenesis in Drosophila melanogaster, but which genes participate together with dy for wing morphogenesis has remained unclear. In Tribolium castaneum, dy is highly expressed at the late embryonic stage. Tissue-specific expression analysis indicated high expression levels of dy in the epidermis, head and fat body of late-stage larvae. RNA interference (RNAi) targeting dy significantly decreased adult wing size and caused improper folding of the elytra. Meanwhile, dy knockdown reduced the transcription of four-jointed (fj) and forked (f). Our results show that fj RNAi reduces adult wing size and that silencing f results in abnormal wing folding in T.castaneum. Interestingly, knocking down fj and f simultaneously phenocopies dy RNAi, suggesting that dy probably acts upstream of fj and f to regulate wing morphogenesis in T.castaneum.

Nonlinear Dynamics of Z-Shaped Folding Wings with 1:1 Inner Resonance

Predicting the nonlinear vibration responses of a Z-shaped folding wing during the morphing process is a prerequisite for structural design analysis. Therefore, the present study focuses on the nonlinear dynamical characteristics of a Z-shaped folding wing. The folding wing is divided into three carbon fiber composite plates connected by rigid hinges. The nonlinear dynamic equations of the system are derived using Hamilton’s principle based on the von Kármán equations and classical laminate plate theory. The mode shape functions of the system are then obtained using finite element analysis. Galerkin’s approach is employed to discretize the partial differential governing equations into a two-degree-of-freedom nonlinear system. The case of 1:1 inner resonance is considered. The method of multiple scales is employed to obtain the averaged equations of the system. Finally, numerical simulation is performed to investigate the nonlinear dynamical characteristics of the system. Bifurcation diagrams and wave-form diagrams illustrate the different motions of the Z-shaped folding wing, including periodic and chaotic motions under given conditions. The influence of transverse excitations on the bifurcations and chaotic motion of the Z-shaped folding wing is investigated numerically.