Computational Modeling of Spanwise Flexibility Effects on Flapping Wing Aerodynamics

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76845/1/AIAA-2009-1270-256.pd

Computational aeroelasticity framework for analyzing flapping wing micro air vehicles

Published versio

Approximate Aeroelastic Modeling of Flapping Wings: Comparisions with CFD and Experimental Data

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/83577/1/AIAA-2010-2707-714.pd

Approximate Aerodynamic and Aeroelastic Modeling of Flapping Wings in Hover and Forward Flight

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90666/1/AIAA-2011-2008-958.pd

Dynamic simulation and optimization of artificial insect-sized flapping wings for a bioinspired kinematics using a two resonant vibration modes combination

This paper addresses the design of the elastic structure of artificial wings to optimize their dynamical behaviour to reproduce insect wings kinematics. Our bioinspired kinematics is based on the original concept of using the resonant properties of the wing structure in order to combine the motion of two vibration modes, a flapping and a twisting mode, in a quadrature phase shift. Oneway of achieving this particular combination is to optimize the geometry and elastic characteristics of the flexible structure such that the two modes are successive in the eigenspectrum and close in frequency. This paper first proposes a semi-analytical model, based on assembled Euler-Bernoulli beams, to understand, compute and optimize the artificial wing dynamic vibrations. Then, using this model, it is shown that it is possible to obtain several artificial wing structures with a flapping and a twisting mode close in frequency. Finally, experimental validations are performed on micromachined insect-sized prototypes to validate the model and the concept

Influence of Structural Flexibility on Flapping Wing Propulsion

The inelastic deformation behavior of PMR-15 neat resin, a high-temperature thermoset polymer, was investigated at 288 degrees C. The experimental program was designed to explore the influence of strain rate on tensile loading, unloading, and strain recovery behaviors. In addition, the effect of the prior strain rate on the relaxation response of the material, as well as on the creep behavior following strain controlled loading were examined. The experimental data were modeled with the Viscoplasticity Based on Overstress (VBO) theory. A systematic procedure for determining model parameters was developed and the model was employed to predict the response of the material under various test histories. Additionally the effects of prior aging at 288 degrees C in argon on the time (rate)-dependent behavior of the PMR-15 polymer were evaluated in a series of strain and load controlled experiments. Based on experimental results, the VBO theory was extended to capture the environmentally induced changes in the material response. Several of the VBO material parameters were expanded as functions of prior aging time. The resulting model was used to predict the high-temperature behavior of the PMR-15 polymer subjected to prior aging of various durations

ポリマー微細加工によって作成される羽ばたき翼微小飛行体のデザインウィンドウ探索法による開発

The specific flight mechanisms of insects like hovering and maneuverability along with their tiny size nature grasp the attention of many researchers across the globe to utilize the phenomena for the development of biomimetic flapping wing air vehicles which can be used in the wide areas like hazardous environment exploration, rescue, agriculture, pipeline inspection, and earthquake or tsunami disaster management, etc where human access is difficult. Consequently, many researchers have developed flapping wing air vehicles ranging from macro scale to the nanoscale (the largest dimension should be less than or equal to 10 cm) i.e., flapping-wing nano air vehicles (FWNAVs). The research on insect-inspired FWNAVs indicates that FWNAVs generally consist of micro transmission for getting desired flapping motion, a pair of micro wings, an actuator for the power source, and a supporting frame to support the overall structure. Recently, FWNAVs up to a size of 30 mm have been developed based on the insect’s size. However, the evolution of insects indicates that the size of ultimate small insects is about 1 mm. The further miniaturization of current FWNAVs is difficult because of the large assembly of components and complicated mechanical transmission mechanism. Though, there are mainly two difficulties to successfully developing FWNAVs at the scale of mm-size. The first is the manufacturing difficulty because of the very small structure to realize the wing’s complicated motions. The second is the design difficulty because of multisystem and involvement of coupled Multiphysics like fluid-structure interaction (FSI) design. Along with these difficulties other difficulty includes enough lift to drag ratio for hover and thrust for forwarding flight motion due to fluid mechanics at low Reynolds no (Re < 3000). These difficulties can be overcome by developing FWNAVs based on a design window search methodology where a design solution can be obtained for the design problem satisfying all the design requirements. Further fabricating the FWNAVs using advanced engineering technologies such as microelectromechanical systems (MEMS) technologies which seem to be suitable for mm-size prototypes. Computational analysis and design can be utilized for finding the design window search for FWNAVs. The finite element method (FEM) has been the standard choice as a numerical tool for performing the simulation of Multisystem, because of its capabilities to analyze the geometries of complex shapes, detailed analysis of coupled effect, boundary, and initial conditions. The purpose of this study is to develop 10 mm insect-inspired FWNAV using a 2.5-dimensional structure novel approach, iterative design window search methodology, and polymer micromachining. The proposed FWNAV consists of a micro transmission with a support frame, a micro wing, and a piezoelectric bimorph actuator. The novelty of this research includes, (1) the novel transmission mechanism using two parallel elastic hinges based on geometrically nonlinear bending deformation that produces a large rotational displacement from a small translational displacement, (2) the complete 2.5-D structure which can be fabricated using the polymer micromachining technique without any post-assembly (3) the novel design approach or iterative design window (DW) search method using the advanced computational analysis and design. The advantage of the proposed FWNAV over other FWNAVs includes the lowest energy loss due to no post assembly (friction loss is less), reducing total weight, ease in miniaturization, and enough performance without resonance mechanism. In order to develop the proposed FWNAV, firstly I have designed micro transmissions with a support frame and micro wing and later I have designed FWNAV which has been further miniaturized to design 10mm FWNAV using the iterative DW search method. I have also estimated fatigue life arising due to random cyclic stress, which is mostly ignored by the researchers. Computational flight performance of the proposed FWNAV has been evaluated using Multiphysics coupled analysis i.e., fluid-structure interaction analysis where governing equilibrium equation of motion of micro wing and surrounding airflow has been directly solved by finite element methods. The computational flight performance indicates that mean lift force is comparable to the weight of FWNAV which provides that the proposed FWNAV can lift off. The polymer micromachining has been demonstrated by fabricating the transmission which is a key and central component of FWNAV which indicates the feasibility of polymer micromachining for the development of 10 mm FWNAV. Thus, 10 mm flyable FWNAV can be developed which has enough fatigue life.九州工業大学博士学位論文 学位記番号：情工博甲第369号 学位授与年月日：令和4年9月26日1 General Introduction|2 Proposal of 2.5-dimensional one wing transmission for flapping-wing nano air vehicle|3 Iterative design window search for polymer micromachined flapping-wing nano air vehicle|4 Computational flight performance of flapping wing nano air vehicles using fluid-structure interaction analysis|5 Development of flapping-wing nano air vehicle|6 General Conclusion九州工業大学令和4年