A comparative study of the effects of constructional elements on the mechanical behaviour of dragonfly wings

Abstract

Although wings of insects show a large variation in morphology, they are all made from a network of irregular veins interconnected through membranous areas. Depending on their shape, size, and position, wing veins are usually divided into three different groups: longitudinal veins, cross-veins and ambient veins. The veins together with the membrane and some other elements such as spines, nodus and pterostigma can be considered as the wing’s “constructional elements”. In spite of rather extensive literature on dragonfly wing structure, the role of each of these elements in determining the wing’s function remains mostly unknown. As this question is difficult to answer in vivo using biomechanical experiments on actual wings, this study was undertaken to reveal the effects of the constructional elements on the mechanical behaviour of dragonfly wings by applying numerical simulations. An image processing technique was used to develop 12 finite element models of the insect wings with different constructional elements. The mechanical behaviour of these models was then simulated under normal and shear stresses due to tension, bending and torsion. A free vibration analysis was also performed to determine the resonant frequencies and the mode shapes of the models. For the first time, a quantitative comparison was carried out between the mechanical effects selectively caused by different elements. Our results suggest that the complex interactions of veins, membranes and corrugations may considerably affect the dynamic deformation of the insect wings during flight

A simple developmental model recapitulates complex insect wing venation patterns

“…1A; see SI Appendix for details). This categorization of veins is similar to those used in previous studies (24,25).…”

Effect of microstructure on the mechanical and damping behaviour of dragonfly wing veins

“…It has been shown that longitudinal veins, especially those situated close to the leading edge, dramatically enhance the stiffness of wings in the spanwise direction [ 2 , 5 , 8 ]. Numerical simulations indicate that the presence of longitudinal veins also improves the natural frequencies of both fore- and hindwings of dragonfly Orthetrum Sabina (Anisoptera, Libellulidae) approximately twofold, and therefore avoids structural failure due to resonance [ 9 ]. What are the underlying factors that cause the unique mechanical behaviour exhibited by insect wing veins?…”

The forewing of the Aphis fabae (Scopoli 1763) (Hemiptera, Sternorrhyncha): a morphological and histological study

“…Around veins thickened cuticle creates reinforcements, usually depicted as convex (above wing membrane as cuticular ridges in dorsal view) or concave (as cuticular grooves in ventral view), which cause wings corrugation (Kukalová-Peck 1978 ; Appel et al 2015 ). Until now, it has been believed that only veins strengthen the wings, but actually it is achieved thanks to the interaction of veins, wing membrane, and corrugations (Rajabi et al 2016a ).…”

“…A few other studies were recently carried out on wings of Orthoptera (Wootton et al 2000 ), Lepidoptera (O`Hara and Palazotto 2012 ), Coleoptera (Sun et al 2014 ), and Odonata (Appel et al 2015 ; Rajabi et al 2016a , b ), whose wings are bigger and more rigid than those of Sternorrhyncha.…”