Testing Method and Design Guideline of Unit Cell Shape of Cellular Structures Made of AZ31 Magnesium Alloy Considering Application to Coronary Stent

Ichiro Shimizu, Shunpei Ueda, Akira Wada, Tomoya Kagotani and Yoshito Takemoto

Coronary stents are thin-walled cellular structures constructed by connecting unit cells in the circumferential and axial directions. The unit cell is subjected to in-plane bending during the expansion process in the diseased artery. As the simple test method to evaluate the in-plane bending and contribute to the design of the stent unit cell shape, the rhombus-shaped specimen having the curved part and the straight part was suggested. The experimental and analytical investigations were performed on the rhombus specimen made of AZ31 magnesium alloy, and the influences of the design parameters on the strain gradient in the curved part and the deformability were investigated. The results proved that the rhombus-shaped specimen was useful to investigate the in-plane bending of the cellular structure. The in-plane strain gradient from tensile to compressive was found to occur in the curved part. Changing the design parameters of the rhombus specimen influences not only the deformability but also the tensile load, namely the force to keep the artery open. It should be emphasized that the addition of the appropriate length of a central straight part was found to be effective in improving the deformability of the cellular structure.

Advanced Experimental Mechanics

Vol. 8

7 pages

10.11395/aem.24-0007

https://doi.org/10.11395/aem.24-0007