Study On Mechanical Properties Of Niti Alloy Iliac Vein Stent

Iliac vein compression syndrome is the main cause of disturbance of venous and pelvic venous return.And the most important is that long term iliac vein stenosis can cause venous hypertension or deep venous thrombosis.However,at present,the stents used for the iliac venous disease are arterial stents and almost imported from abroad.For this reason,the mechanical properties,fluid solid coupling characteristics of four nickel titanium iliac vein stents under different release scales were studied by the methods of numerical simulation.1)The change of expansion diameter has little effect on the maximum equivalent stress,maximum elastic strain,supporting and bending stiffness of stents.However,the nominal diameter of stents is obviously related to the maximum equivalent stress,maximum elastic strain,the supporting and flexural performance of stents.2)When stents are expanded,the elastic strain of the supporting arc area,which is a dangerous area,is the largest.Therefore,it is necessary to consider how to reduce the strain in dangerous area and improve safety in design.3)From the results of elastic strain distribution of stent fatigue strength and fluid solid coupling simulation,it is found that under the action of pulsating cyclic loading and blood flow,the elastic strain of stent also occurs in the circular area of supporting body.When fatigue strength of supporting body fails to meet the requirements,it is prone to fatigue failure such as collapse,crack.4)After stent implantation,the velocity of blood flow and blood disturbance were reduced,but it did not affect the blood flow velocity and caused the phenomenon of blood flow or eddy current.And It did not break the laminar flow of blood flow.Therefore,the different release scales of the stent have little effect on flow velocity of iliac vein,the total displacement and elastic strain of blood vessel and stents.To provide a scientific reference for the design and clinical application of nickel titanium alloy stent iliac vein,this paper,through makeing a systematic analysis of the mechanical properties and fluid solid coupling characteristics,reproduced the deformation process of stents,restored the complex blood flow,and summed up the effects of different release scale of stents on the effects of mechanical properties,hemodynamics and fluid solid coupling characteristic of nitinol iliac vein stents.