Using the method of structural finite element topology optimization and analysis of the hindwings of Trypoxylus dichotomus,this work identified the main loading force transmission path and designed the initial structu...Using the method of structural finite element topology optimization and analysis of the hindwings of Trypoxylus dichotomus,this work identified the main loading force transmission path and designed the initial structure of a bionic flexible wing.A structural design scheme of the vibration damping unit was proposed,and the structural mechanics and modal vibration characteristics were simulated and analyzed.3D printing technology was used to manufacture the designed bionic wing skeleton,which was combined with two kinds of wing membrane materials.The Flapping Wing Micro-aerial Vehicle(FWMAV)transmission mechanism vibration characteristics were observed and analyzed by a high-speed digital camera.A triaxial force transducer was used to record the force vibration of the flexible bionic wing flapping in a wind tunnel.A wavelet processing method was used to process and analyze the force signal.The results showed that the force amplitude was more stable,the waveform roughness was the lowest,and the peak shaving phenomenon at the z-axis was the least obvious for the bionic flexible wing model that combined the topology-optimized bionic wing skeleton with a polyamide elastic membrane.This was determined to be the most suitable design scheme for the wings of FWMAVs.展开更多
A numerical analysis has been conducted to study the role of hindfoil initial pitch angle on aerodynamic performance of dragonfly hovering flight.The inclined oscillation of two elliptic airfoils with tandem arrangmen...A numerical analysis has been conducted to study the role of hindfoil initial pitch angle on aerodynamic performance of dragonfly hovering flight.The inclined oscillation of two elliptic airfoils with tandem arrangment at Re=157 is analysed using 2D numerical simulation.The pitch amplitude(α_(m))is kept constant for both foils and hindfoil initial pitch angle(α_(Oh))is varied from 15° to 75° for three different phase oscillations:φ=0°,90° and 180°.The results indicate,for α_(Oh)<45°,the lower α_(Oh) reduces total lift for all phase differences.It occurs due to the detrimental wake capture and downward dipole jet encountered by hindfoil during downstroke,resulting in less hindfoil C_(V).However,for α_(Oh)>45o,lift enhancement of up to 46% is observed with increase in α_(Oh) during φ=180°.Also,the higher thrust is obtained during lower α_(Oh) and it reduces with increase in α_(Oh).展开更多
基金supported by the National Natural Science Foundation of China(grant number 31970454)the Aviation Science Foundation of China(2020Z0740R4001)+1 种基金the Graduate Innovation Fund of Jilin University(2022189)Undergraduate Innovation and Entrepreneurship Training Program Project of Jilin University(S202210183259).
文摘Using the method of structural finite element topology optimization and analysis of the hindwings of Trypoxylus dichotomus,this work identified the main loading force transmission path and designed the initial structure of a bionic flexible wing.A structural design scheme of the vibration damping unit was proposed,and the structural mechanics and modal vibration characteristics were simulated and analyzed.3D printing technology was used to manufacture the designed bionic wing skeleton,which was combined with two kinds of wing membrane materials.The Flapping Wing Micro-aerial Vehicle(FWMAV)transmission mechanism vibration characteristics were observed and analyzed by a high-speed digital camera.A triaxial force transducer was used to record the force vibration of the flexible bionic wing flapping in a wind tunnel.A wavelet processing method was used to process and analyze the force signal.The results showed that the force amplitude was more stable,the waveform roughness was the lowest,and the peak shaving phenomenon at the z-axis was the least obvious for the bionic flexible wing model that combined the topology-optimized bionic wing skeleton with a polyamide elastic membrane.This was determined to be the most suitable design scheme for the wings of FWMAVs.
文摘A numerical analysis has been conducted to study the role of hindfoil initial pitch angle on aerodynamic performance of dragonfly hovering flight.The inclined oscillation of two elliptic airfoils with tandem arrangment at Re=157 is analysed using 2D numerical simulation.The pitch amplitude(α_(m))is kept constant for both foils and hindfoil initial pitch angle(α_(Oh))is varied from 15° to 75° for three different phase oscillations:φ=0°,90° and 180°.The results indicate,for α_(Oh)<45°,the lower α_(Oh) reduces total lift for all phase differences.It occurs due to the detrimental wake capture and downward dipole jet encountered by hindfoil during downstroke,resulting in less hindfoil C_(V).However,for α_(Oh)>45o,lift enhancement of up to 46% is observed with increase in α_(Oh) during φ=180°.Also,the higher thrust is obtained during lower α_(Oh) and it reduces with increase in α_(Oh).
