Optimization of vascular stent for its flexibility based on response surface method and strength reliability analysis of vascular stent caused by machining accuracy
Objective A parameterized model of vascular stents was established,and vascular stent was optimized for its flexibility.Based on the optimization results,the uncertainty of design dimensions caused by machining accuracy was considered,and the strength probability analysis of vascular stents was conducted to verify the reliability of the optimization results.Methods The structural features were explored to establish a parameterized model of vascular stents.The bending stiffness was taken as the optimization objective,and the width of the stent strut,the length of the stent strut,the width of the stent link,and the thickness of the vascular stent were the design variables.The response surface method was used for optimization design.Candidate design point with low local stress sensitivity was selected as the optimal design points.Based on the optimized vascular stent,the design dimensions caused by machining accuracy were taken as random variables,and the strength probability analysis of the vascular stent was conducted using the six sigma analysis tool.Results Compared to the original stent,the bending stiffness of the optimized vascular stent decreased by 32.91％.The maximum stress of the vascular stent met the strength requirements when the reliability reached 99.85％.Conclusion The width of the stent link had the greatest impact on the flexibility of the vascular stent,followed by the thickness of the stent,and the length and width of stent strut had a smaller impact.Strength of the optimized vascular stent under the influence of processing accuracy was reliable.Vascular stents are affected by some uncertainty factors in engineering practice.After conducting deterministic optimization design,the uncertainty of design variables caused by uncertainty factors should be considered for strength reliability analysis verification.
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