An experimental study of the elastic properties of dragonfly-like flapping wings for use in Biomimetic Micro Air Vehicles (BMAV)

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 10–250 Hz. 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

A review on the orthotics and prosthetics and the potential of kenaf composites as alternative materials for ankle-foot orthosis

Since ancient Egypt, orthosis was generally made from wood and then later replaced with metal and leather which are either heavy, bulky, or thick decreasing comfort among the wearers. After the age of revolution, the manufacturing of products using plastics and carbon composites started to spread due to its low cost and form-fitting feature whereas carbon composite were due to its high strength/stiffness to weight ratio. Both plastic and carbon composite has been widely applied into medical devices such as the orthosis and prosthesis. However, carbon composite is also quite expensive, making it the less likely material to be used as an Ankle-Foot Orthosis (AFO) material whereas plastics has low strength. Kenaf composite has a high potential in replacing all the current materials due to its flexibility in controlling the strength to weight ratio properties, cost-effectiveness, abundance of raw materials, and biocompatibility. The aim of this review paper is to discuss on the possibility of using kenaf composite as an alternative material to fabricate orthotics and prosthetics. The discussion will be on the development of orthosis since ancient Egypt until current era, the existing AFO materials, the problems caused by these materials, and the possibility of using a Kenaf fiber composite as a replacement of the current materials. The results show that Kenaf composite has the potential to be used for fabricating an AFO due to its tensile strength which is almost similar to polypropylene's (PP) tensile strength, and the cheap raw material compared to other type of materials

Experimental analysis on drilling process of composite laminates

This thesis deals with carbon fiber reinforced plastics (CFRP) composites, an advanced material which is widely used in manufacturing aircrafts because of their unique mechanical and physical properties. The research mainly involved drilling of CFRP. This study focused on analyzing the thrust force and delamination against drilling parameters namely feed rate, spindle speed and type of tool materials. Also, the optimal parameters were chosen using an optimization method called D optimal. It was observed that the higher the feed rate and spindle speed employed, the higher the thrust force and delamination that occurs. The optimal parameters obtained were 221.72mm/min for feed rate, 2000 rpm for spindle speed and the most suitable tool chosen was the SPF drill. A verification test was conducted and the percentage error obtained for delamination was 5.6% and for thrust force was only 2.3%. This shows, that the optimal parameters obtained is reliable as it could improve the process considerably.The results of this study could be used as a reference for further research and studies on drilling of CFRP. -Author

Development of an optimal dragonfly-like flapping wing structure for use in biomimetic micro air vehicles / Praveena Nair Sivasankaran

Biomimetic Micro Air Vehicles (BMAV) are unmanned, micro-scaled aircrafts that are bioinspired from flying organisms to achieve lift and thrust by flapping their wings. Micro Air Vehicles (MAV) are a relatively new and rapidly growing area of aerospace research. They were first defined by the US Defense Advanced Research Projects Agency (DARPA) in 1997 as unmanned aircraft that are less than 15 cm in any dimension. This allows BMAV to potentially be smaller and more lightweight than the other two types. These characteristics make BMAV ideally suited for flight missions in confined areas (e.g. around power lines, narrow streets, indoors, etc.). Therefore, BMAV structural components must be ultra-lightweight, compact, and flexible. Most past MAV research has focused on fixed wings, which are essentially scaled-down versions of wings on conventional fixed wing aircraft. These wings are unsuitable for BMAV due to their lack of flexibility. So a new type of structural wing design is required for BMAV. In this work, a dragonfly wing structure is mimicked to construct a new BMAV wing design. A dragonfly (Odonata) was selected for biomimicry, because they are highly maneuverable flyers, capable of hovering, rapid forward flight, or reverse flight. Therefore, structurally analyzing these wings could yield results that inspire the design of more effective wings for BMAVs. The overall objective of this research is to develop a simplified wing model for a BMAV, bioinspired from actual dragonfly wings. A simplified model was created using spatial network analysis, a topological optimization method. These simplified wing frame models were then fabricated using seven different types of materials. Stainless steel type 321, balsa wood, red pre-impregnated fiberglass, black graphite carbon fiber, polyvinyl acid, acrylic and acrylo-nitirile butadiene styrene. These wing frame structures were fabricated using laser cutting machine and a 3D printer. These wing frames were then immersed in a chitin-chitosan membrane by a casting method. These wing frames were subjected to iv mechanical testing’s such as bending and tensile to study its suitability for use in a BMAV. A flapping mechanism was also created and used to produce flapping motion on these BMAV wings and an actual dragonfly wing (for comparison). The aero elastic properties of both the BMAV and actual dragonfly wings were examined using two high speed frame camera. The bending angle, displaced distance or deflection, wing tip angle, and the wing tip rotational twist speed were analyzed at the flapping frequencies of 10,20, 30 Hz, 60 Hz and 120 Hz

Spatial network analysis to construct simplified wing structural models for Biomimetic Micro Air Vehicles

A procedure for designing a simplified, dragonfly-like wing model that is suitable for use in a Biomimetic Micro Air Vehicle (BMAV) is presented. BMAV are a relatively new class of micro-scaled unmanned air systems that mimic the flapping wing propulsion system of flying biological organisms (like insects). Many insects (e.g. dragonflies) have complex wing vein and membrane patterns that are too small to fabricate using many types of machine cutting tools (e.g. micro laser cutting). Structural dynamic modification using the spatial network analysis approach is used to create a simplified model. Our objective was to minimize the wing vein patterns so that they were within our fabrication tolerances. Simulations were performed for both the detailed and simplified models. The natural frequency and corresponding mode shapes, modal assurance criterion (MAC) and static bend-twist coupling results were very similar. This analysis shows that a simplified model can be designed and fabricated to closely biomimic a real dragonfly wing

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

AbstractThis 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