Figure 1 Rhombus structure of stent with 4 rhombus units – 8 struts [11]

Figure 2 a) Reduced stent model used for axisymmetric structural analysis b) the reduced balloon model along the length c) The reduced stent with balloon combined model used for axisymmetric structural analysis.

Figure 3 a) frictionless contact surfaces b) meshed stent and artery used for analysis

Figure 4 a) Graph showing the displacement boundary condition steps b) Free faces and faces with frictionless supports used in axisymmetric analysis

Figure 5 SS 316L: a) Maximum equivalent Von Mises stress when the balloon is fully expanded b) residual stress retained by the stent after deflation of balloon c) maximum total deformation at fully expanded condition d) total deformation due to recoiling when the balloon deflates e) Maximum displacement along X at fully expanded balloon and f) displacement along X after recoiling.

Figure 6CoCrFeNiMn: a) Maximum equivalent Von Mises stress when the balloon is fully expanded b) residual stress retained by the stent after deflation of balloon c) maximum total deformation at fully expanded condition d) total deformation due to recoiling when the balloon deflates e) Maximum displacement along X at fully expanded balloon and f) displacement along X after recoiling.

Figure 7 Al0.1CoCrFeNi: a) Maximum equivalent Von Mises stress when the balloon is fully expanded b) residual stress retained by the stent after deflation of balloon c) maximum total deformation at fully expanded condition d) total deformation due to recoiling when the balloon deflates e) Maximum displacement along X at fully expanded balloon and f) displacement along X after recoiling.

Parameters

Values

Length

15 mm

Outer diameter

3.0mm

Strut width

0.05mm

Strut thickness

0.05 mm

Longest diagonal of the rhombus

1.62mm

Shortest diagonal of the rhombus

1.18 mm

No. of units along circumference

8

Table 1. Dimensions of the stent model

Material

Yield strength MPa

Ultimate strength MPa

Young's modulus GPa

Tangent modulus GPa

Density kg/m3

Poisson's ratio

SS 316L

    190

    490

    193

1.93

8000

0.3

CoCrFeNiMn

    216

    475

    189

   0.643

7954

0.3

Al0.1CoCrFeNi

    212

   570

    203

   0.843

7950

0.3

Table 2. Mechanical properties of SS 316L and Al0.1CoCrFeNi and CoCrFeNiMn HEAs added to ANSYS Workbench library

Steps

Time [s]

X [mm]

Y [mm]

Z [mm]

1

0.

0.

  0.

0.

1.

0.75

2

2.

0.

= 0.

= 0.

Table 3: Displacement boundary in cylindrical coordinate system for the balloon

Material

Max Von Mises stress MPa

Max residual stress MPa

Max total deformation mm

Recoil percentage %

SS 316L

410

177

1.156

3.7

CoCrFeNiMn

323

193

1.161

3.2

Al0.1CoCrFeNi

345

191

1.596

3.1

Table 4. Summary of results generated from computational analysis