Journal of Biomaterials and Nanobiotechnology, 2013, 4, 247-255 doi:10.4236/jbnb.2013.43031 Published Online July 2013 (http://www.scirp.org/journal/jbnb) 247 Tensile Properties of Veins of Damselfly Wing Rupan Talucdher, Kunigal Shivakumar * Center for Composite Materials Research (CCMR), Department of Mechanical Engineering, North Carolina A & T State University (NC A & T SU), Greensboro, USA. Email: * kunigal@ncat.edu Received March 30 th , 2013; revised April 30 th , 2013; accepted May 15 th , 2013 Copyright © 2013 Rupan Talucdher, Kunigal Shivakumar. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. ABSTRACT Microtension test of Costa and Radius veins of damselfly wing was conducted to measure tensile strength and modulus. The specimens were classified into fresh and dry depending on when the samples were prepared and tested. Fresh sam- ples tested immediately after extracting from the fly while the dry samples were tested one year after extraction and stored in a desiccator. Measured load-displacement response and fracture load were used to calculate modulus and strength. Field Emission Scanning Electron Microscope was used to measure the fracture morphology and cross-section of the vein. The results showed that the veins are brittle and fracture surface is flat. The average strength (232 - 285 MPa) and modulus (14 - 17 GPa) of the Costa and Radius veins were nearly same for both fresh and dry samples. The tensile modulus of the veins was 8% - 10% higher than the indentation (compressive) modulus and was nearly the same as that of human bones. Keywords: Damselfly Wing; Microtension Test; Tensile Strength; Tensile Modulus; Micro Air Vehicle 1. Introduction Ambulatory parts of an insect consist of living and non- living parts. Using these parts, insects can fly, crawl, walk or jump. Understanding the ambulation of insects is helpful in simulation of or building autonomous micro- system. The lifting force of this insect wing is about ten times that of an equivalent aircraft wing [1]. A damselfly is considered in this study because of its versatile features and its applicability for micro air vehicle (MAV). Dam- selfly wings are stiff and ultra lightweight that makes them to flap at very high frequency and maintain stability. To- tal mass of wings is 1% - 2% of mass of the insect. Thus, a study of the insect wings helps to advance existing fly- ing systems including materials and structural concepts. Biological branch and species name of the North Caro- lina (NC) damselfly (see Figure 1(a)) are Odonata and Lestes sp, respectively, as stated by Combes and Daniel [2]. Figure 1(a) shows four wings of the fly and Figure 1(b) shows a microscopic detail of a typical wing. The wing length (distance between proximal end and distal end) varied from 20 to 25 mm and the cord length (dis- tance between leading edge and trailing edge) varied from 5 to 6 mm. The wing is composed mainly of veins (stiff member) and membrane (filler material). The major veins of the wing are Costa, Subcosta, Radius and other minor veins (see Figure 1(b)). Nodus and petrostigma/ stigma are two distinctive features of the wings. The nodus lies in the leading edge of the wing and Subcosta ends on nodus. The petrostigma, like a fuscous mark, is situated near the tip. The nodus and the petrostigma im- prove the flexibility of wing and prevent fatigue fracture [3]. The petrostigma performs balancing of the mass, sta- bilizes flight at high speed and eliminates any airflow vibrations. If the petrostigma is cut off the dragonfly could still fly but the flight becomes unstable [4]. The basic material of the insect vein is made of chitin, a long chain polymer of N-acetyl-glucosamine that is similar to cellulose or keratin materials [5]. The flying behavior of insects is strongly related to the physical properties of wing [1,6-8]. If the wing structural features and the ma- terial properties are known then one could fabricate a synthetic wing by the right choice of commercial materi- als. Furthermore, the wings flying response is directly related to its material and structural properties. Quantitative measurements of the mechanical proper- ties of insect wing, namely, the vein and membrane are useful in development of bio-mimetic system suitable for MAVs. Different wing zones bear different loads, and * Corresponding author. Copyright © 2013 SciRes. JBNB