Wing Frame Research Articles

Mathematical modelling for compliance-assisted artificial muscle based ornithopter

PurposeThis study aims to discuss the mathematical modelling of a compliance-assisted flapping mechanism and morphable structures for an UAV.Design/methodology/approachA compliance-assisted flapping wing was designed and modelled mathematically, and signals for the corresponding curves were calculated. The actual wing tip trace of a hummingbird was taken, and variables a, b, h and k were calculated from the image. This data was given to the mathematical model for plotting the graph, and the curve was compared with the input curve. The wing frame and mechanism for control surfaces using morphing is modelled along with single pivoted spine for centre of gravity augmentation and flight orientation control.FindingsThe model efficiently approximates the 2D path of the wing using line segments using the muscle and compliance mechanism.Practical implicationsUsing a compliance-assisted flapping mechanism offers practical advantages. It allows us to synchronize the flapping frequency with the input signal frequency, ensuring efficient operation. Additionally, the authors can enhance the torque output by using multiple muscle strands, resulting in a substantial increase in the system’s torque-to-weight ratio. This approach proves to be more favourable when compared to conventional methods involving motors or servos, ultimately offering a more efficient and robust solution for practical application.Social implicationsThis model focuses on creating a flexible and tunable mechanism that can at least trace four types of wing traces from the same design, for shifting from one mode of flight to another.Originality/valueConventional ornithopter flapping mechanisms are gear or servo driven and cannot trace a wing tip, but some can trace complicated curves, but only one at a time. This model can trace multiple curves using the same hardware, allowing the user to program the curve based on their needs or bird. The authors may vary the shape of the wing tip trace to switch between forward flight, hovering, backward flying, etc., which is not conceivable with any traditional flapping mechanism.

Service Life Modelling of Single Lap Joint Subjected to Cyclic Bending Load

Bonded joints used in wing sections and frames of aircraft structures are mostly exposed to cyclic loadings instead of static ones during their services. Bending types of dynamic loadings are mostly encountered. In this study, the fatigue response of a single lap joint (SLJ) exposed to bending loading was studied with the developed advanced finite-element (FE) model. The cohesive zone model describing the behaviour of the adhesive layer used the damage mechanism, where static and fatigue damages were linked to each other; i.e., the total damage was accumulated because of material deterioration and cyclic plastic separation. This enabled us to predict the fatigue characteristics including the finite fatigue life, crack propagation rate using Paris law. The model was implemented via a user-defined UMAT subroutine offered in ABAQUS-Standard. The numerical model was validated by experiments available in the literature. The fatigue performance of an SLJ subjected to bending loading was investigated for different lap joint configurations. A smaller bending load, a thicker adherend or a longer overlap length (OL) led to enhanced fatigue life. For instance, the fatigue life was observed to increase up to 50 times for a 66% increase in OL.

Design and analysis of a tail sitter (VTOL) UAV composite wing

In recent years the design and development of various classes of unmanned aerial vehicles (UAV's) has grown significantly. It is a well-known fact that the utilization of composite structures will reduce the weight of the aircraft structure by 30–50%. It is possible to tailor the strength and stiffness properties of composite structures by adopting different material or lamination configurations. In this work redesign of the Tail Sitter (Vertical Take Off and Landing/VTOL) UAV wing is carried out in order to improve the performance by reduction of the weight. Numerical investigation is carried out to reduce the weight of the wing by replacing the existing Aluminum frame with different ply configurations of CFRP and GFRP and also by reducing number of spars. The strength and stiffness of the UAV wing was analysed by Finite Element Method. Baseline analysis was carried out on the Aluminium structure by applying the span wise lift distribution along the wing based on Dr Ing Oster Schrenk’s Approximation method. For the VTOL UAV configuration the wing has to carry the motor, so structurally wing should have higher stiffness-to weight ratio to carry the high loads. The present work was focussed on analysis of different ply configurations of CFRP as well as GFRP using FE methods in order to get better performance in terms of weight reduction. The analysis was done by configuring the whole wing frame along with spars and ribs, which gave high stiffness to the wing compared to the Conventional wing. From the CFD analysis, it is evident that composite wing had less deformation compared to the aluminium wing and the wing structure was redesigned using CFRP and GFRP based composites. Effect of lay-up configuration on the performance is also studied for composite wing. Due to high stiffness to weight ratio of composite wing it is found there is a reduction in weight of the wing by 44.17% compare to aluminium. A redesign of the wing is done by having a composite frame of two spars and five Ribs.

Выбор оптимальной конструктивно-силовой схемы лонжеронного композитного крыла

This paper describes a method for optimizing the design of a spar-type composite aircraft wing structure based on multi-criterion approach. Two types of composite wing structures such as two-spar and three-spar ones were considered. The optimal design of a wing frame was determined by the Pareto method basing on three criteria: minimal weight, minimal wing deflection, maximal safety factor and minimal weight. Positions of wing frame parts, i.e. spars and ribs, were considered as optimization parameters. As a result, an optimal design of a composite spar-type wing was proposed. All the calculations necessary to select the optimal structural and design of the spar composite wing were performed using nonlinear static finite element analysis in the FEMAP with NX Nastran software package.

Insect wing 3D printing

Insects have acquired various types of wings over their course of evolution and have become the most successful terrestrial animals. Consequently, the essence of their excellent environmental adaptability and locomotive ability should be clarified; a simple and versatile method to artificially reproduce the complex structure and various functions of these innumerable types of wings is necessary. This study presents a simple integral forming method for an insect-wing-type composite structure by 3D printing wing frames directly onto thin films. The artificial venation generation algorithm based on the centroidal Voronoi diagram, which can be observed in the wings of dragonflies, was used to design the complex mechanical properties of artificial wings. Furthermore, we implemented two representative functions found in actual insect wings: folding and coupling. The proposed crease pattern design software developed based on a beetle hindwing enables the 3D printing of foldable wings of any shape. In coupling-type wings, the forewing and hindwing are connected to form a single large wing during flight; these wings can be stored compactly by disconnecting and stacking them like cicada wings.

W. E. B. Du Bois's Data Portraits: Visualizing Black America ed. by Whitney Battle-Baptiste and Britt Rusert

Reviewed by: W. E. B. Du Bois's Data Portraits: Visualizing Black America ed. by Whitney Battle-Baptiste and Britt Rusert Christopher McAuley W. E. B. Du Bois's Data Portraits: Visualizing Black America. Ed. Whitney Battle-Baptiste and Britt Rusert. Hudson, NY: Princeton Architectural Press, 2018. Pp. 144 + 63 illustrations. $29.95 (cloth). "Black America in Technicolor" is what may come to mind as one studies the vividly colored and creatively designed maps, bar graphs, pie charts, and other shapes that W. E. B. Du Bois and his collaborators used to represent Black America at the Exposition Universelle in Paris at the opening of the twentieth century, now assembled and published for the first time by Whitney Battle-Baptiste and Britt Rusert in W. E. B. Du Bois's Data Portraits: Visualizing Black America. So accustomed are we to viewing social scientific data in black and white that we can forget that the originals, in some cases, were vibrantly rendered in the full spectrum of colors. But as the editors and contributors—Aldon Morris, Mabel O. Wilson, and Silas Munro—make clear in their short but effective contextual essays and commentaries, the choice of hues was only one part of the Du Bois team's strategy of data representation. No less important to its members were the configuration and layout of the numerical and statistical information, fully cognizant of the fact that to challenge hardened perceptions, like racial ones, the researcher must appeal to the senses as much to the intellect. Hence, their use of a variety of geometric shapes, angles, planes, symbols, lettering, and fonts in their "infographics." The results are exceedingly striking visual representations of data that one has to literally see to appreciate, especially those that Du Bois's team constructed to convey Black migrations and measures of social progress in literacy, landownership, and school enrollment. Our contemporary visual renderings of data look drab and flatly unimaginative in comparison. A firm believer in the independent power of empirical data Du Bois may well have been, but he also understood, like any Parisian boutiquier, that there is power in presentation. [End Page 196] The volume contains reproductions of all sixty-three "data visualizations" that were part of the American Negro Exhibit, and are divided into the categories that Du Bois's "design team" chose: The Georgia Negro: A Social Study and A Series of Statistical Charts Illustrating the Condition of the Descendants of Former African Slaves Now in Residence in the United States of America. Accompanying each plate are informative and suggestive remarks by Munro, describing how the Du Bois team's visual innovations anticipate later artistic movements. As the editors and contributors note, the aim of the Du Bois team was to present Black America at the state, national, and international levels, so as to move exhibit attendees to locate Black America in global history and processes, including their particular experience of racial enslavement. Also included in the volume is a reproduction of a photo of the exhibit area of the American Negro Exhibit, which shows the framed and mounted infographics along the back and side walls, as well as those in double-sided wing frames. The photo also reveals the other "eclectic set of objects, images, and texts" that Du Bois's team assembled in the exhibit area, including framed photographic portraits of prominent African American leaders and politicians; tools, harnesses, and other agricultural products from black industrial schools; a bronze statuette of Frederick Douglass; and an on-site collection of over two hundred and fifty publications authored by African Americans and compiled by Daniel Alexander Payne Murray. (9) The photo, along with the editors' inventory of the archive that the Du Bois team used to represent Black America, allow the reader to imagine how white European and North American passers-by, on-lookers, and the curious received that information and what they later related to others about it. We have no way of knowing if the committee that awarded Du Bois a gold medal for coordinating the American Negro Exhibit at the Exposition Universelle did so because its members were genuinely convinced of the central points of the exhibit's designers: that Black American...

Approach to optimization of composite aircraft wing structure

This paper describes an approach to optimization of composite aircraft wing structure basing on multi-criterion method. Two types of composite wing structures such as two-spar and three-spar ones were considered. The optimal layout of a wing frame was determined by Pareto optimization method basing on three criteria: minimal wing deflection, maximal safety factor and minimal weight. Positions of internal wing frame parts (spars and ribs) were considered as optimization parameters. As a result, an optimal design of a composite spar-type wing was proposed.

Decoupled Effects of Localized Camber and Spanwise Bending for Flexible Thin Wing

Investigated and revealed are new insights into the individual, decoupled effects of induced camber and spanwise bending on the lift, drag, and endurance for an optimum flexibility membrane-and-frame wing at Reynolds number 80,000. While previous studies into thin, flexible-wing designs for fixed-wing unmanned aerial vehicles have been shown to improve aerodynamic performance and delay the onset of stall, the individual contributions of localized induced camber and spanwise bending on the performance improvement have not been sufficiently examined. Furthermore, since the locally induced camber and spanwise bending generally occur simultaneously, their decoupled effects are not well understood. This Paper first introduces a wing frame optimization approach using a rapid fluid/structure interaction model to identify a wing flexibility design that maximizes aerodynamic endurance. A higher-fidelity, large-eddy simulation is then used for validation of the optimized wing flexibility and to help explain both the coupled and uncoupled effects of the induced camber and spanwise bending that contribute to maximum performance. The formation of several locally induced cambers at specific planform regions is found to create greater endurance (minimum power required) through favorable lift generation, in addition to reduced drag at relatively high angles of attack. Spanwise bending, however, is observed to be a noncontributing byproduct of the increased thin-wing flexibility. Detailed pressure distributions and instantaneous flow structure visualizations from large-eddy simulation provide new insights into the individual contributions of induced camber and spanwise bending while also justifying the optimum wing design.

New conceptual design of the adaptive compliant aircraft wing frame

Two design solutions are proposed for the development of an adaptive compliant aircraft wing frame using reconfigurable honeycomb core based on a network of joints with hidden topological surfaces. The first design solution utilizes the lever actuators integrated with the honeycomb structure of the wing frame, the second one uses actuators in the form of mechatronic nodes. In addition, this research outlines the development potential of the ideas on the using of smart materials and artificial muscles. Applied use of the dynamic spatial forms can be extended to many industrial and utility products and, in general, is aimed at filling the object-spatial environment with objects of dynamic functionality and aesthetics. The objective of future studies in this topic is to implement the topological optimization of the reconfigurable honeycomb core and selecting various cell form combinations optimal for each instance.

Structural analysis of flexibility matrices of the curvature rods

Currently, significant interest among the developers of navigation devices, particularly dynamically tuned gyros, is caused by the design of elastic elements with specified properties. In turn, the development of optimal designs of elastic elements that provide the necessary rigidity of an airplane wing is of significant relevance. At the same time, if optimization is carried out, for example, within the framework of the conceptual design stage, which allows of certain simplifications, then it is advisable to apply its idealized core structure to correctly reproduce the most significant features of the wing frame powerwork.

Optimal Sensor Placement Based on Eigenvalues Analysis for Sensing Deformation of Wing Frame Using iFEM.

For real time monitoring of the wing state, in this paper, the inverse Finite Element Method (iFEM) is applied, which describes the displacement field of beam according to the Timoshenko theory, to sense the wing frame deformation. In order to maintain the accuracy and stability of frame deformation sensing with iFEM, an optimal placement model of strain sensors based on eigenvalue analysis is constructed. Through the model solution with the Particle Swarm Optimization (PSO) algorithm, two different optimal placement schemes of sensors are obtained. Finally, a simulation is performed on a simple cantilever beam and a static load experiment is conducted on an aluminum alloy wing frame. The results demonstrate that the iFEM is able to accurately sense the deformation of the wing frame, when the two optimal placement schemes of sensors are used.

Nano-mechanical properties and structural of a 3D-printed biodegradable biomimetic micro air vehicle wing

The biomimetic micro air vehicles (BMAV) are unmanned, micro-scaled aircraft that are bio-inspired from flying organisms to achieve the lift and thrust by flapping their wings. The main objectives of this study are to design a BMAV wing (inspired from the dragonfly) and analyse its nano-mechanical properties. In order to gain insights into the flight mechanics of dragonfly, reverse engineering methods were used to establish three-dimensional geometrical models of the dragonfly wings, so we can make a comparative analysis. Then mechanical test of the real dragonfly wings was performed to provide experimental parameter values for mechanical models in terms of nano-hardness and elastic modulus. The mechanical properties of wings were measured by nanoindentre. Finally, a simplified model was designed and the dragonfly-like wing frame structure was bio-mimicked and fabricated using a 3D printer. Then mechanical test of the BMAV wings was performed to analyse and compare the wings under a variety of simplified load regimes that are concentrated force, uniform line-load and a torque. This work opened up the possibility towards developing an engineering basis for the biomimetic design of BMAV wings.

Investigation of hindwing folding in ladybird beetles by artificial elytron transplantation and microcomputed tomography

Ladybird beetles are high-mobility insects and explore broad areas by switching between walking and flying. Their excellent wing transformation systems enabling this lifestyle are expected to provide large potential for engineering applications. However, the mechanism behind the folding of their hindwings remains unclear. The reason is that ladybird beetles close the elytra ahead of wing folding, preventing the observation of detailed processes occurring under the elytra. In the present study, artificial transparent elytra were transplanted on living ladybird beetles, thereby enabling us to observe the detailed wing-folding processes. The result revealed that in addition to the abdominal movements mentioned in previous studies, the edge and ventral surface of the elytra, as well as characteristic shaped veins, play important roles in wing folding. The structures of the wing frames enabling this folding process and detailed 3D shape of the hindwing were investigated using microcomputed tomography. The results showed that the tape spring-like elastic frame plays an important role in the wing transformation mechanism. Compared with other beetles, hindwings in ladybird beetles are characterized by two seemingly incompatible properties: (i) the wing rigidity with relatively thick veins and (ii) the compactness in stored shapes with complex crease patterns. The detailed wing-folding process revealed in this study is expected to facilitate understanding of the naturally optimized system in this excellent deployable structure.

An experimental study of elastic properties of dragonfly-like flapping wings for use in biomimetic micro air vehicles (BMAVs)

This article studies the elastic properties of several biomimetic micro air vehicle (BMAV) wings that are based on a dragonfly wing. BMAVs are a new class of unmanned micro-sized air vehicles that mimic the flapping wing motion of flying biological organisms (e.g., insects, birds, and bats). Three structurally identical wings were fabricated using different materials: acrylonitrile butadiene styrene (ABS), polylactic acid (PLA), and acrylic. Simplified wing frame structures were fabricated from these materials and then a nanocomposite film was adhered to them which mimics the membrane of an actual dragonfly. These wings were then attached to an electromagnetic actuator and passively flapped at frequencies of 10–250Hz. A three-dimensional high frame rate imaging system was used to capture the flapping motions of these wings at a resolution of 320 pixels×240 pixels and 35000 frames per second. The maximum bending angle, maximum wing tip deflection, maximum wing tip twist angle, and wing tip twist speed of each wing were measured and compared to each other and the actual dragonfly wing. The results show that the ABS wing has considerable flexibility in the chordwise direction, whereas the PLA and acrylic wings show better conformity to an actual dragonfly wing in the spanwise direction. Past studies have shown that the aerodynamic performance of a BMAV flapping wing is enhanced if its chordwise flexibility is increased and its spanwise flexibility is reduced. Therefore, the ABS wing (fabricated using a 3D printer) shows the most promising results for future applications.

Monitoring the Shape of Satellite Wing Frame Using FBG Sensors in High Electronic Noise, Vacuum, and −196 °C Environment

In a normal environment on Earth, there are several methods for obtaining the deflection curve of a satellite wing frame, such as the laser method and the electronic resistance strain gauge method. However, none of them are suitable for the outer space environment. Therefore, developing a reliable sensing solution for a high electronic noise, vacuum, and extremely low-temperature environment may be a very challenging task. In this paper, a new fiber Bragg grating (FBG) sensors method is proposed to meet this harsh environment need. First, hundreds of FBG sensors are pasted onto the surface of a satellite wing frame to detect the strain data. Second, the cubic spline interpolation function, quadratic integral function, and quantic polynomial function are used for the data processing to obtain the shape of the satellite wing frame. Finally, a satellite wing frame is placed in a heat sink to conduct a shape monitoring experiment. Furthermore, a verification experiment in a normal environment shows the reliability of the FBG sensors method. Because the FBG sensors and the supporting equipment are available in the market, this method is a feasible solution for shape monitoring in outer space.

Design and mechanical analysis of a 3D-printed biodegradable biomimetic micro air vehicle wing

The biomimetic micro air vehicles (BMAV) are unmanned, micro-scaled aircraft that are bio-inspired from flying organisms to achieve the lift and thrust by flapping their wings. There are still many technological challenges involved with designing the BMAV. One of these is designing the ultra-lightweight materials and structures for the wings that have enough mechanical strength to withstand continuous flapping at high frequencies. Insects achieve this by having chitin-based, wing frame structures that encompass a thin, film membrane. The main objectives of this study are to design a biodegradable BMAV wing (inspired from the dragonfly) and analyze its mechanical properties. The dragonfly-like wing frame structure was bio-mimicked and fabricated using a 3D printer. A chitosan nanocomposite film membrane was applied to the BMAV wing frames through casting method. Its mechanical performance was analyzed using universal testing machine (UTM). This analysis indicates that the tensile strength and Young's modulus of the wing with a membrane is nearly double that of the wing without a membrane, which allow higher wing beat frequencies and deflections that in turn enable a greater lifting performance.

Static strength analysis of dragonfly inspired wings for biomimetic micro aerial vehicles

This article examines the suitability of fabricating artificial, dragonfly-like, wing frames from materials that are commonly used in unmanned aircraft (balsa wood, black graphite carbon fiber and red prepreg fiberglass). Wing frames made with Type 321 stainless steel are also examined for comparison. The purpose of these wings is for future use in biomimetic micro aerial vehicles (BMAV). BMAV are a new class of unmanned micro-sized aerial vehicles that mimic flying biological organisms (like flying insects). Insects, such as dragonflies, possess corrugated and complex vein structures that are difficult to mimic. Simplified dragonfly-like wing frames were fabricated from these materials and then a nano-composite film was adhered to them, which mimics the membrane of an actual dragonfly. Finite element analysis simulations were also performed and compared to experimental results. The results showed good agreement (less than 10% difference for all cases). Analysis of these results shows that stainless steel is a poor choice for this wing configuration, primarily because of the aggressive oxidation observed. Steel, as well as balsa wood, also lacks flexibility. In comparison, black graphite carbon fiber and red prepreg fiberglass offer some structural advantages, making them more suitable for consideration in future BMAV applications.

Modal Analysis of Hummingbird Inspired MAV Flapping Wings

Natural flyers are the best source of inspiration for making successful MAVs. Hummingbirds are known for their excellent flight characteristics such as long duration hovering, backward flying, high agility, etc. Giant hummingbird is chosen as the bio-inspiration for designing the wing. Wings are required to be light, strong, and fatigue resistant to be used for MAV applications. Carbon nanotubes (CNTs)/Polypropylene (PP) composite is chosen as the wing membrane material whereas carbon fiber (CF)/epoxy (E) composite is chosen for wing frame. Two types of wings are fabricated, one is CNTs/PP wing and another is CF/E frame with CNTs/PP membrane wing. Kinematics, structural dynamics, and aerodynamics are the main component of flapping flight studies. Modal analysis of fabricated wings is done using 3D visual image correlation (VIC-3D) and laser displacement sensor setup. In the end, the results of both type wings are compared with experimental results and a good correlation has been seen. The validation of results is done using Ansys.

Experimental analysis of artificial dragonfly wings using black graphite and fiberglass for use in Biomimetic Micro Air Vehicles (BMAVs)

This article examines the suitability of two different materials which are black graphite carbon fiber and red pre-impregnated fiberglass from which to fabricate artificial dragonfly wing frames. These wings could be of use in Biomimetic Micro Aerial Vehicles (BMAV). BMAV are a new class of unmanned micro-sized air vehicles that mimic flying biological organisms. Insects, such as dragonflies, possess corrugated and complex vein structures that are difficult to mimic. Simplified dragonfly wing frames were fabricated from these materials and then a nano-composite film was adhered to them, which mimics the membrane of an actual dragonfly. Experimental analysis of these results showed that although black graphite carbon fiber and red pre-impregnated fiberglass offer some structural advantages, red pre-impregnated fiberglass was a less preferred option due to its warpage and shrinking effects. Black graphite carbon fiber with its high load bearing capability is a more suitable choice for consideration in future BMAV applications.

Three-dimensional flow visualization and vorticity dynamics in revolving wings

We investigated the three-dimensional vorticity dynamics of the flows generated by revolving wings using a volumetric 3-component velocimetry system. The three-dimensional velocity and vorticity fields were represented with respect to the base axes of rotating Cartesian reference frames, and the second invariant of the velocity gradient was evaluated and used as a criterion to identify two core vortex structures. The first structure was a composite of leading, trailing, and tip-edge vortices attached to the wing edges, whereas the second structure was a strong tip vortex tilted from leading-edge vortices and shed into the wake together with the vorticity generated at the tip edge. Using the fundamental vorticity equation, we evaluated the convection, stretching, and tilting of vorticity in the rotating wing frame to understand the generation and evolution of vorticity. Based on these data, we propose that the vorticity generated at the leading edge is carried away by strong tangential flow into the wake and travels downwards with the induced downwash. The convection by spanwise flow is comparatively negligible. The three-dimensional flow in the wake also exhibits considerable vortex tilting and stretching. Together these data underscore the complex and interconnected vortical structures and dynamics generated by revolving wings.