The Biomechanical Properties Of Magnesium Alloy Stent In The Process Of Degradation

Magn esium alloy stents has grad ually become t he preferred o f i nterventio nal treatment of cardi ovascular disease. Ho wever, the mechanical i ntegrity of stent wil l be d amaged during the remodeli ng of t he vessel wall, b y t he magnesi um alloy stent degrad atio n. The mechanical properties is the mos t i mp ortant indicator o f stents applied i n the clinical. Therefore, i t’s necessary to evaluate the stent mechanical i ntegrity d uring the d egradation. In this paper,efforts have b een made to analyz e t he mechanical properties of the s tent in t he pro cess of degradation by finite element met hod and mat erial tes ts.The material parameters of AZ91 D magnesium al loy in the process of corrosio n were t ested throu gh the tensile exp eri men t. Corrosio n morph ology were stu died by s canning electroni c micros copy(SEM), and corrosion rate of magnesium alloy were by studied stati c weightless-n ess experiments and electrochemi cal experimen t. It was found that the elas tic modulus and ten sile strength of AZ9 1D and the size of stent are reduci ng, and pitting corrosion was happened on magn esium alloy surface.The three-d imen sional model of s tent was established by finite element analysi s software, to analyze the biomechanical properties of biodegradablestent in the process of degradation i n Hank’s solution. The results showed that in the process o f deg radat ion, the Vo n Mises stress and equiv alent strain distrib uti on of st ent are affected main ly by the size of stent, the Max stress and strain d ecrease and always ap pear inside o f the stent arms, an d t he ratios of Max stress an d tensile str ength are falling. In ad dit ion, the flexibility of stent was improved, wh ile uneven deformat ion of the structure of stent o ccured during deformation of bending.In th is paper, t he resulte indicat e that the change o f s tent s size during the degradation of magnesium al loy s tent leads to the d ecrease of b iomechanical perfo rmance. It provi des reference for the structural optimization and design of biodegradable magnesiu m alloy stent, and provi des b asis for cli nical ap plication of degrad able magnesium alloy s tent s.