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The goal of a new research study is to understand the mechanism of Nitinol ultra-high cycle fatigue and to eventually predict when fracture will occur. Nitinol's remarkable qualities including recoverable [...]

Computer simulations using methods such as finite element analysis (FEA) play an important role in the design of implantable medical devices that are manufactured from superelastic materials like nickel-titanium (NiTi) [...]

A computational methodology for simulating virtual inferior vena cava (IVC) filter placement and WC hemodynamics was developed and demonstrated in two patient-specific IVC geometries: a left-sided IVC and an IVC with a retroaortic left renal vein. An inverse analysis was performed to obtain the approximate in vivo stress state for each patient vein using nonlinear finite element analysis (FEA). Contact modeling was then used to simulate IVC filter placement. Contact area, contact normal force, and maximum vein displacements were higher in the retroaortic FVC than in the left-sided IVC (144 mm, 0.47 N, and 1.49 mm versus 68 mm², 0.22 N, and 1.01 mm, respectively). Hemodynamics were simulated using computational fluid dynamics (CFD), with four cases for each patient-specific vein: (1) IVC only, (2) IVC with a placed filter, (3) IVC with a placed filter and model embolus, all at resting flow conditions, and (4) IVC with a placed filter and model embolus at exercise flow conditions. Significant hemodynamic differences were observed between the two patient IVCs, with the development of a right-sided jet, larger flow recirculation regions, and lower maximum flow velocities in the left-sided IVC. These results support further investigation of IVC filter placement and hemodynamics on a patient-specific basis. [ABSTRACT FROM AUTHOR]

• Examples of rigorous code verification for solid mechanics are rare in literature. • Verification evidence is especially lacking for nonlinear analyses and commercial codes. • We use the method of manufactured solutions (MMS) to verify a commercial code. • Common linear and nonlinear elastostaic problems are considered. • We observe second-order displacement and first-order stress and strain convergence. • Source code and simulation files are provided to facilitate future MMS studies. Much progress has been made in advancing and standardizing verification, validation, and uncertainty quantification practices for computational modeling in recent decades. However, examples of rigorous code verification for solid mechanics problems in literature remain scarce, particularly for commercial software and for the non-trivial large-deformation analyses and nonlinear materials typically needed to simulate medical devices. Here, we apply the method of manufactured solutions (MMS) to verify a commercial finite element code for elastostatic solid mechanics analyses using linear-elastic, hyperelastic (neo-Hookean), and quasi-hyperelastic (Hencky) constitutive models. Analytical source terms are generated using Python/SymPy and are implemented in ABAQUS/Standard without modification to solver source code. Source terms for the three constitutive models are found to vary nearly six orders of magnitude in the number of mathematical operations they contain. Refinement studies reveal second-order displacement and first-order (or higher) stress and strain convergence in response to mesh refinement for all constitutive models and first-order displacement convergence in response to pseudo-time increment refinement for the Hencky-elastic case. We also investigate the sensitivity of convergence order to quantitatively minor changes to the underlying mathematical model using an exploratory case. Code used to generate the MMS source terms and simulation input files are provided as Supplemental Material. [ABSTRACT FROM AUTHOR]