NUMERICAL INVESTIGATIONS OF THE FLEXIBILITY OF INTRAVASCULAR BRAIDED STENT

Braided stents are commonly used to treat cerebral aneurysm, but there is little information about the bending characteristic of braided stent used for cerebral aneurysm. This paper investigates how geometrical parameters of braided stent influence its flexibility. Eight groups of braided stent models with different geometries (i.e., nominal diameter, length, braiding angle, number of wires, diameter of wire, frictional coefficient among wires and porosity) were constructed. Parametric analyses of these models were carried out by using Abaqus/Explicit. When the nominal diameter varied from 2 mm to 5.5 mm, the forces required for flexural deformation decrease from 2.64E - 04N to 1.06E - 04 N; when the axial length varied from 10mm to 40 mm, the forces required for flexural deformation decrease from 2.16E - 04N to 4.38E - 05 N; when the braiding angle increases from 30 degrees to 75 degrees (the number of wires is 48 and the diameter of the wire is 0.026 mm), the forces required for bending deformation decrease from 2.3E - 03N to 2.4E - 04 N; when the diameter of wires increases from 0.026 mm to 0.052 mm (the number of wires is 24 and the braiding angle is 60 degrees), the forces required for flexural deformation increase from 1.0E - 04N to 9.3E - 04 N; and when the number of wires increases from 14 to 48 (the braiding angle is 75 degrees and the diameter of the wire is 0.026 mm), the forces required for flexural deformation increase from 2.1E - 05N to 2.4E - 04 N. From the data above it can be seen that the diameter of wires, the number of wires and braiding angle have a larger impact on bending characteristics of braided stent; and the axial length and nominal diameter have a smaller impact on bending characteristics of braided stent. Results of the present study may provide theoretical guidance for the design of self-expanding braided stent and its clinical practice.