Medical devices, particularly endovascular stents, manufactured from superelastic Nitinol, a nearequiatomic alloy of Ni and Ti, are subjected to complex mixed-mode loading conditions in vivo, including axial tension and compression, radial compression, pulsatile, bending and torsion. Fatigue lifetime prediction methodologies for Nitinol, however, are invariably based on uniaxial loading and thu...

Atomically smooth graphene as a surface coating has potential to improve implant properties. This demonstrates a method for coating nitinol alloys with nanometer thick layers of graphene for applications as a stent material. Graphene was grown on copper substrates via chemical vapor deposition and then transferred onto nitinol substrates. In order to understand how the graphene coating could ch...

Mechanical devices are sought to support insufficient or paralysed striated muscles including the failing heart. Nickel-titanium alloys (nitinol) present the following two properties: (i) super-elasticity, and (ii) the potential to assume different crystal structures depending on temperature and/or stress. Starting from the martensite state nitinol is able to resume the austenite form (state of...

Medical devices, particularly endovascular stents, manufactured from superelastic Nitinol, a near-equiatomic alloy of Ni and Ti, are subjected to complex mixed-mode loading conditions in vivo, including axial tension and compression, radial compression, pulsatile, bending and torsion. Fatigue lifetime prediction methodologies for Nitinol, however, are invariably based on uniaxial loading and th...

A method has been developed in which three-dimensional structures of nitinol thin film are fabricated using a sequence of processes that involve alternating sputter deposition of multiple layers and Micro-ElectroMechanical-Systems (MEMS) photolithographic steps. The multiple-layered nitinol parts are transformed into integral three-dimensional shapes by “shape-setting” annealing process using s...

The mechanical properties of Nitinol stents are normally evaluated experimentally due to complexities resulting from large deformations and material nonlinearity. Despite the difficulties associated with Finite Element Analysis (FEA), the success of the computational analysis in combination with experimental study leads to better understanding of stent performance. This paper presents compariso...

Nitinol, a group of nearly equiatomic shape memory and superelastic NiTi alloys, is being extensively explored for medical applications. Release of Ni in the human body, a potential problem with Nitinol implant devices, has stimulated a great deal of research on its surface modifications and coatings. In order to use any of the developed surfaces in implant designs, it is important to understan...

This article presents two applications of the nonlinear finite element analysis (FEA) using ABAQUS/Standard with a user developed material subroutine Nitinol UMAT from Abaqus West. The analyses are found to agree well with the theoretical prediction and/or experimental measurement. In that first example, FEA predicts the stress-strain response of a superelastic Nitinol device at different Af te...

Aim: This literature review was aimed to find out which kind of interactions result from the use of Nitinol in the oral system. In particular the main interest was directed to the alterations of the oral tissues as well as to the effects on distant districts. Conclusions: Nitinol is a mostly tolerated material, widely used in orthodontic for its useful properties. Nevertheless negative reaction...

BACKGROUND Microinvasive glaucoma surgery (MIGS) is a relatively new addition to the glaucoma treatment paradigm. Small metallic stents are inserted into the trabecular meshwork in order to increase aqueous humour drainage. MIGS procedures are rapidly being adopted owing to a more favourable side effect profile when compared with traditional surgery. Remarkably, this rapid rate of utilization h...