Modeling of braided stents: Comparison of geometry reconstruction and contact strategies

Zaccaria, Alissa; Migliavacca, Francesco; Pennati, Giancarlo; Petrini, Lorenza

doi:10.1016/j.jbiomech.2020.109841

Cited by 26 publications

(20 citation statements)

References 37 publications

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“…Mathematical models have provided a considerable insight into the complex mechanical behavior of NiTi. Most of the models in the literature have not been able to simulate the following prevalent NiTi phenomena: cyclic instability of superelasticity, actuation instability, shape setting, two-way SME, and functional thermomechanical fatigue [ 43 , 74 ]. Several constitutive models have been created over the years to capture this complex behavior, following either of the two approaches—micromechanical (microscale) or phenomenological (macroscale).…”

Section: Methodsmentioning

confidence: 99%

“…Numerical methods, including finite element analysis (FEA) methods, allow the analysis of complex problems, comprising intricate geometries, interactions, nonlinearities, and dynamic conditions. In the past, FEA models have been used to study the response of NiTi components, such as when printing stents and actuator springs [ 43 ]. Several works have been conducted to evaluate the post-implantation structural and functional response [ 44 , 45 , 46 ], and degradation and fatigue-related studies [ 47 , 48 , 49 ].…”

Section: Introductionmentioning

confidence: 99%

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Influence of Structural Porosity and Martensite Evolution on Mechanical Characteristics of Nitinol via In-Silico Finite Element Approach

et al. 2022

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Nitinol (NiTi) alloys are gaining extensive attention due to their excellent mechanical, superelasticity, and biocompatibility properties. It is difficult to model the complex mechanical behavior of NiTi alloys due to the solid-state diffusionless phase transformations, and the differing elasticity and plasticity presenting from these two phases. In this work, an Auricchio finite element (FE) model was used to model the mechanical behavior of superelastic NiTi and was validated with experimental data from literature. A Representative Volume Element (RVE) was used to simulate the NiTi microstructure, and a microscale study was performed to understand how the evolution of martensite phase from austenite affects the response of the material upon loading. Laser Powder Bed Fusion (L-PBF) is an effective way to build complex NiTi components. Porosity being one of the major defects in Laser Powder Bed Fusion (L-PBF) processes, the model was used to correlate the macroscale effect of porosity (1.4–83.4%) with structural stiffness, dissipated energy during phase transformations, and damping properties. The results collectively summarize the effectiveness of the Auricchio model and show that this model can aid engineers to plan NiTi processing and operational parameters, for example for heat pump, medical implant, actuator, and shock absorption applications.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Influence of Structural Porosity and Martensite Evolution on Mechanical Characteristics of Nitinol via In-Silico Finite Element Approach

et al. 2022

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“…The ID Branch was built using 3D parametric equations. 27 The geometrical parameters were evaluated based on pictures of the stent in the extended configuration, in order to improve the similarity with the real device. Then, a preliminary compression simulation was carried out to achieve the original shape (Fig.…”

Section: Methodsmentioning

confidence: 99%

Finite Element Simulations of the ID Venous System to Treat Venous Compression Disorders: From Model Validation to Realistic Implant Prediction

et al. 2021

Self Cite

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The ID Venous System is an innovative device proposed by ID NEST MEDICAL to treat venous compression disorders that involve bifurcations, such as the May-Thurner syndrome. The system consists of two components, ID Cav and ID Branch, combined through a specific connection that prevents the migration acting locally on the pathological region, thereby preserving the surrounding healthy tissues. Preliminary trials are required to ensure the safety and efficacy of the device, including numerical simulations. In-silico models are intended to corroborate experimental data, providing additional local information not acquirable by other means. The present work outlines the finite element model implementation and illustrates a sequential validation process, involving seven tests of increasing complexity to assess the impact of each numerical uncertainty separately. Following the standard ASME V&V40, the computational results were compared with experimental data in terms of force-displacement curves and deformed configurations, testing the model reliability for the intended context of use (differences < 10%). The deployment in a realistic geometry confirmed the feasibility of the implant procedure, without risk of rupture or plasticity of the components, highlighting the potential of the present technology.

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“…Nevertheless, an optimal radial pressure is required to avoid post-deployment recoil and migration (Li and Kleinstreuer, 2006). The radial pressure is a function of stent structural parameters and the material properties, which has been extensively studied for braided stents (Zaccaria et al, 2020;Kim et al, 2008), Z stents (Snowhill et al, 2001), and closed-cell venous stents (Dabir et al, 2018). In venous stenting, oversizing the stent is a common technique to avoid recoil and migration.…”

Section: Introductionmentioning

confidence: 99%

Deformation Mechanics of Self-expanding Venous Stents: Modelling and Experiments

Hejazi¹,

Sassani²,

Gagnon³

et al. 2021

Preprint

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Deformation properties of venous stents based on braided design, chevron design, Z design, and diamond design are compared using in vitro experiments coupled with analytical and finite element modelling. Their suitability for deployment in different clinical contexts is assessed based on their deformation characteristics. Self-expanding stainless steel stents possess superior collapse resistance compared to Nitinol stents. Consequently, they may be more reliable to treat diseases like May-Thurner syndrome in which resistance against a concentrated (pinching) force applied on the stent is needed to prevent collapse. Braided design applies a larger radial pressure particularly for vessels of diameter smaller than 75% of its nominal diameter, making it suitable for a long lesion with high recoil. Z design has the least foreshortening, which aids in accurate deployment. Nitinol stents are more compliant than their stainless steel counterparts, which indicates their suitability in veins. The semi-analytical method presented can aid in rapid assessment of topology governed deformation characteristics of stents and their design optimization.

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Modeling of braided stents: Comparison of geometry reconstruction and contact strategies

Cited by 26 publications

References 37 publications

Influence of Structural Porosity and Martensite Evolution on Mechanical Characteristics of Nitinol via In-Silico Finite Element Approach

Influence of Structural Porosity and Martensite Evolution on Mechanical Characteristics of Nitinol via In-Silico Finite Element Approach

Finite Element Simulations of the ID Venous System to Treat Venous Compression Disorders: From Model Validation to Realistic Implant Prediction

Deformation Mechanics of Self-expanding Venous Stents: Modelling and Experiments

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