Development of flapping wing aerial vehicle (FWAV) has been of interest in the aerospace community with ongoing research into unsteady and low Reynolds number aerodynamics based on the vortex lattice method. Most of t...Development of flapping wing aerial vehicle (FWAV) has been of interest in the aerospace community with ongoing research into unsteady and low Reynolds number aerodynamics based on the vortex lattice method. Most of the previous research has been about pitching and plunging motion of the FWAV. With pitching and flapping motion of FMAV, people usually study it by experiment, and little work has been done by numerical calculation. In this paper, three-dimension unsteady vortex lattice method is applied to study the lift and thrust of FWAV with pitching and flapping motion. The results show that: 1) Lift is mainly produced during down stroke, however, thrust is produced during both down stroke and upstroke. The lift and thrust produced during down stroke are much more than that produced during upstroke. 2) Lift and thrust increase with the increase of flapping frequency;3) Thrust increases with the increase of flapping amplitude, but the lift decreases with the increase of flapping amplitude;4) Lift and thrust increase with the increase of mean pitching angle, but the effect on lift is much more than on thrust. This research is helpful to understand the flight mechanism of birds, thus improving the design of FWAV simulating birds.展开更多
Recent studies of flapping-wing aerial vehicles have been focused on the aerodynamic performance based on linear materials. Little work has been done on structural analysis based on nonlinear material models. A stress...Recent studies of flapping-wing aerial vehicles have been focused on the aerodynamic performance based on linear materials. Little work has been done on structural analysis based on nonlinear material models. A stress analysis is conducted in this study on membrane flapping-wing aerial vehicles using finite element method based on three material models, namely, linear elastic, Mooney-Rivlin non linear, and composite material models. The purpose of this paper is to understand how different types of materials affect the stresses of a flapping-wing. In the finite element simulation, each flapping cycle is divided into twelve stages and the maximum stress is calculated in each stage. The results show that 1) there are two peak stress values in one flapping cycle;one at the beginning stage of down stroke and the other at the beginning of upstroke, 2) maximum stress at the beginning of down stroke is greater than that at the beginning of upstroke, 3) maximum stress based on each material model is different. The composite and the Mooney-Rivlin nonlinear models produce much less stresses compared to the linear material model;and 4) the ratio of downstroke maximum stress and upstroke maximum stress varies with different material models. This research is helpful in answering why insect wings are so impeccable, thus providing a possibility of improving the design of flapping-wing aerial vehicles.展开更多
文摘Development of flapping wing aerial vehicle (FWAV) has been of interest in the aerospace community with ongoing research into unsteady and low Reynolds number aerodynamics based on the vortex lattice method. Most of the previous research has been about pitching and plunging motion of the FWAV. With pitching and flapping motion of FMAV, people usually study it by experiment, and little work has been done by numerical calculation. In this paper, three-dimension unsteady vortex lattice method is applied to study the lift and thrust of FWAV with pitching and flapping motion. The results show that: 1) Lift is mainly produced during down stroke, however, thrust is produced during both down stroke and upstroke. The lift and thrust produced during down stroke are much more than that produced during upstroke. 2) Lift and thrust increase with the increase of flapping frequency;3) Thrust increases with the increase of flapping amplitude, but the lift decreases with the increase of flapping amplitude;4) Lift and thrust increase with the increase of mean pitching angle, but the effect on lift is much more than on thrust. This research is helpful to understand the flight mechanism of birds, thus improving the design of FWAV simulating birds.
文摘Recent studies of flapping-wing aerial vehicles have been focused on the aerodynamic performance based on linear materials. Little work has been done on structural analysis based on nonlinear material models. A stress analysis is conducted in this study on membrane flapping-wing aerial vehicles using finite element method based on three material models, namely, linear elastic, Mooney-Rivlin non linear, and composite material models. The purpose of this paper is to understand how different types of materials affect the stresses of a flapping-wing. In the finite element simulation, each flapping cycle is divided into twelve stages and the maximum stress is calculated in each stage. The results show that 1) there are two peak stress values in one flapping cycle;one at the beginning stage of down stroke and the other at the beginning of upstroke, 2) maximum stress at the beginning of down stroke is greater than that at the beginning of upstroke, 3) maximum stress based on each material model is different. The composite and the Mooney-Rivlin nonlinear models produce much less stresses compared to the linear material model;and 4) the ratio of downstroke maximum stress and upstroke maximum stress varies with different material models. This research is helpful in answering why insect wings are so impeccable, thus providing a possibility of improving the design of flapping-wing aerial vehicles.
