Chiral petal honeycomb metamaterial structures: Biomimetic design and application in vascular stents.

Auxetic structure has a very good application prospect in biomedical engineering as implant and stent design, but this scenario faces the difficulty of synergistic optimization of multiple performance indexes. This paper aims to break through this dilemma through innovative design concepts and methods. The study integrates bio-morphology and engineering biomimicry to design a chiral petal-type honeycomb structure by extracting the cross symmetry of cruciferous plant petals and the mechanical properties of wind turbine blades. The whole process framework of "bio-morphological feature extraction-parametric modeling -- multi-objective optimization -- application" is constructed. The neural network model is used to carry out multi-objective prediction, parameter sensitivity analysis, and structure optimization with the help of differential evolutionary algorithm. It is found that the designed structure greatly improves the adjustable range of negative Poisson's ratio, and at the same time, a smaller value of the chiral parameter la can make the structure improve the load carrying capacity in the elastic phase. Simulation of the balloon-expandable stent-vessel coupling process shows that the chiral petal-type cellular stent has outstanding advantages in reducing the stenosis rate maintaining the structural stability and dispersing the stress in the vessel wall among the three cellular structures. This study provides innovative technological solutions for medical device design, and is expected to promote the translation of metamaterial honeycomb structures from theoretical research to practical applications in the field of biomedical engineering, pointing out the direction of focusing on the optimization of key parameters and expanding the clinical applications for subsequent studies.