Analysis of Large Deformation Behavior in Hexagonal-shaped Springs (Towards Deformation Analysis of Indwelling Stent in Blood Vessels)

抄録

In elements used as flexible linking devices and structures, the main characteristic is the occurrence of a fairly large deformation within the elastic limit of the element material. Many of these devices play the role of springs. This property as a spring is of both academical and industrial interests. A hexagonal frame structure is used widely in construction elements, for example, an indwelling stent (:a medical device), a CNT (carbon nanotube), a fishing net, a food net, a gabion, a core of sandwich structures, etc. In such elastic structures, a large deformation characteristic is observed. It is very important to investigate the large deformation behavior quantitatively and qualitatively. However, studies on large deformations have been concerned mainly with a single member (cantilever beam and simple supported beam), and in some particular occasion, cases for multiple members have been analyzed by Kerr and Khwaji. In this paper, a hexagonal frame structure with rigid joints, which is subjected to either tensile or compressive loading diagonally at the pair of opposite frame member or rigid joint was analyzed. Analytical solutions for arc lengths, displacements, deflection angles and bending moments, etc. are derived in terms of elliptic integrals and some solutions are compared with the experimental data. The agreement between analytical and experimental results is found to be fairly close. Therefore, it was proved that the present analytical theory can be effective for large deformation analysis of a hexagonal frame used as a kind of spring. In other words, it was found that the proposed theory would be of great help in elucidating the large deformation of stents with hexagonal structures.