Research of bionic design on tools with rostrum of cyrtotrachelus bugueti guer (coleoptera: curculionidae).

To improve the torsional resistance capability of multilayered composite pipes, a bionic design was presented based on the rostrum of Cyrtotrachelus Bugueti Guer. Morphology and mechanical properties of the weevil's rostrum were studied. Scanning electron microscope (SEM) was employed to observe the macro-/microstructure and inner structure. Nanoindentation was carried out to measure the elastic modulus and the hardness of the biological materials. Based on the structure of rostrum, a mathematical model of multilayered biomimetic pipe was established with the statistical methods. Then, the 3D biomimetic cylinder was built and the torsional resistance capability was analyzed using the finite element analysis. From the SEM and nanoindentation, it was found that the rostrum is a cylindrical hollow multilayered structure composed by three materials. In the transverse section of rostrum, the materials' moduli are 3.07, 3.15, and 8.64 GPa, the hardness are 172.71, 125.32, and 278.99 MPa, respectively. In the longitudinal section, the moduli are 3.01, 4.35, and 7.66 GPa, the hardness are157.46, 149.15, and 253.51 MPa, respectively. The results of simulation showed that the distributional type of lamination has a significant effect on the torsional resistance capability of multilayered structure. The biomimetic structure, which imitates the lamination of rostrum, is superior in the aspect of torsional resistance compared with the nonlaminated or uniform laminated structure. Additionally, the bionic method is feasible and efficient.