Computational Approach for the Fluid-Structure Interaction Design of Insect-Inspired Micro Flapping Wings

Abstract

A flight device for insect-inspired flapping wing nano air vehicles (FWNAVs), which consists of the micro wings, the actuator, and the transmission, can use the fluid-structure interaction (FSI) to create the characteristic motions of the flapping wings. This design will be essential for further miniaturization of FWNAVs, since it will reduce the mechanical and electrical complexities of the flight device. Computational approaches will be necessary for this biomimetic concept because of the complexity of the FSI. Hence, in this study, a computational approach for the FSI design of insect-inspired micro flapping wings is proposed. This approach consists of a direct numerical modeling of the strongly coupled FSI, the dynamic similarity framework, and the design window (DW) search. The present numerical examples demonstrated that the dynamic similarity framework works well to make different two FSI systems with the strong coupling dynamically similar to each other, and this framework works as the guideline for the systematic investigation of the effect of characteristic parameters on the FSI system. Finally, an insect-inspired micro flapping wing with the 2.5-dimensional structure was designed using the proposed approach such that it can create the lift sufficient to support the weight of small insects. The existing area of satisfactory design solutions or the DW increases the fabricability of this wing using micromachining techniques based on the photolithography in the micro-electro-mechanical systems (MEMS) technology. Hence, the proposed approach will contribute to the further miniaturization of FWNAVs.

Elastic storage enables robustness of flapping wing dynamics

“…With combined passive elevation and feathering by introducing two torsional spring models, a significant increase on lift is found under the figure-of-8 mode of wing-tip path, due to the enhanced LEV by upward elevation motion of the flexible wing-hinge [7]. These passive torsional mechanisms associated with wing kinematics in insect flights have been then utilized successfully in designing the bioinspired flapping micro air vehicles (MAV) [8,9]. However, it remains yet poorly studied how the flexible wing hinges function complementarily and interactively with active-actuation and control mechanisms to achieve robust and efficient flapping dynamics, aerodynamic performance and flight stabilization.…”

Computational fluid–structure interaction framework for passive feathering and cambering in flapping insect wings

“…47,67,[70][71][72] The splitting method has been used to investigate passive feathering and elevation motions caused by FSI. 15,[17][18][19]73 Note that, different from our iterative splitting method, it is difficult for direct splitting methods such as block-LU factorization and substructuring in the previous studies to avoid producing Schur complements in the formulation.…”

“…[12][13][14] These motions are based on large elastic deformations produced by aerodynamic and inertial forces induced by the active flapping motion. [15][16][17][18][19][20][21] This claim originally comes from actual observations of the high torsional flexibility of a wing 22,23 and the lack of interior muscles in a wing. 1,24 In flapping insect wings, the veins support the flexible membranes such that the wings form feathering and cambering passively from large elastic deformations.…”

“…Hence, the pixel model wing can change the torsional stiffness of the supports using this parameter while maintaining their flexural stiffness. The time history of the flapping angular velocity, d𝜑/dt, can be expressed using a trapezoidal function as shown in Figure 6A, [15][16][17][18][19] which is based on actual observations. 5,22,23 As shown, the wing flaps with a constant maximum speed 𝜔 max during the middle of each half-stroke and an acceleration/deceleration time t 𝜑 .…”

Importance of Three-Dimensional Piezoelectric Coupling Modeling in Quantitative Analysis of Piezoelectric Actuators

“…Both sensor and actuator modes have been incorporated in intelligent structures [3]. Piezoelectric devices have become increasingly applied in vibration control [4,5], energy harvesting [6][7][8], and nano-aerial vehicles [9][10][11].…”