**3. Design support system for self-expanding stents**

A design support system for a self-expanding stent using CAD and CAE is introduced in this section. This support system can improve the efficiency of the suitable stent design.

### **3.1 Design variables of SENDAI stent**

Figure 7 shows a two-dimensional diagram of a SENDAI stent. Each wire section is constructed from 12 loosely curved S-shaped wires. The strut section of the stent connects them using three bridge wires. On the two-dimensional shape of the SENDAI stent in Fig. 7, the design variables that might affect the mechanical properties of the stent are set. Here, *lw* and *lb* are the length of the wire and the bridge wire along the axial direction, *<sup>w</sup>* and *<sup>b</sup>* are the angle of the wire and the bridge wire to the axial direction, *tw* and *tb* are line element width of the wire and the bridge wire, and *ri* and *ro* are the inner radius and the outer radius of the wire end part. Every wire is structured in an arc shape. When the design variables *lw*, *<sup>w</sup>*, and others are given, the arc shape is determined and wire section is constructed through laying out these arc shapes continuously. Furthermore, the number of wires *nw*, the number of bridge wires *nb*, and the thickness of the tube material *ts* are also design variables.

Fig. 7. Two-dimensional diagram of SENDAI stent (a) and main design variables for SENDAI stent (b)
