medical

In this study we compare various way of quantifying high cycle radial fatigue behavior in a percutaneous Mitral repair device using Goodman methods. In order to provide an improved representation of the tissue-device interaction, we use an Ogden hyperelastic model to  simulate the native vessel with parameters obtained from pressure-diameter test data of human cadaver heart coronary tissue, and published data presented in previous work.

Prediction of respiratory motion has the potential to substantially improve cancer radiation therapy. A nonlinear finite element (FE) model of respiratory motion during full breathing cycle has been developed based on patient specific pressure-volume relationship and 4D Computed Tomography (CT) data. For geometric modeling of lungs and ribcage we have constructed

Computational modeling of stents can provide insight into critical locations (high stress/strain regions), help with design iterations/optimization, and reduce the need for bench-top testing. This study focuses on the developmental efforts to create a material model that can capture the mechanical response of poly-L-lactide (PLLA), the backbone of Abbott Vascular’s ABSORB Bioresorbable Vascular Scaffold (BVS). PLLA is an anisotropic, viscoplastic material.

Endovascular aneurysm repair involves insertion of an introductory component called guidewire through native vessels to help with the guidance of the delivery catheter. Guidewire tends to alter the vessel geometry due to its higher stiffness compared to the vessel wall. Very limited data is available to understand such interactions. Investigation of interaction between guidewire and native vessels could provide useful insight into vessel stresses and guidewire deformation in-vivo.

To enhance the fatigue life of metal components, frequently compressive stress is introduced to the surface layer. Although procedures such as shot peening have been practiced for many decades in other industries, an improved understanding of the fundamental mechanics that leads to the improved performance is desired. From a continuum mechanical point of view, the interaction between the crack and the stress intensity field is the factor determining whether the crack will propagate.

The stresses in a battery housing used in Implantable Pulse Generators (IPGs), also known as pacemakers, were investigated using Abaqus/Standard. There were three levels of analysis: the global level, the three-dimensional submodel level and the plane strain submodel level. The output of the global analysis was fed into the three-dimensional submodel analysis and subsequently the output of the three-dimensional submodel analysis was fed into the plane strain submodel analysis.

Cataract surgery is the most common surgery in America today. Modern surgeries require the opacified crystalline lens to be removed and for a prosthetic lens to be inserted through a suture-less incision during a 5-10 minute outpatient procedure. The industry is driving for smaller incisions by redesigning the lens and insertion device geometry in addition to new materials. Typical lens dimensions are 6mm diameter with a center thickness of 1mm which is inserted through a 2.8mm incision. For the insertion the lens is folded and elongates while advancing down a tapering tube.

The fracture of the proximal humerus is the second most common injury to the upper extremity. In severe fractures, surgery may be necessary which can be in the form of a locking plate holding the bones in place. This study examines the effect of including a bonegraft alongside the locking plate. ScanIP and +ScanCAD (Simpleware Ltd) were used to segment the proximal humerus from a CT scan, and to introduce CAD data of the fixation plate and bonegraft.

Stents have been used in the treatment of coronary artery disease for decades, and their use in the peripheral arterial vasculature is growing rapidly. Mechanical loads imposed on peripheral stents may include loads due to arterial pulsation, axial compression, bending and torsion. These stents are most often manufactured using nitinol, a nickel-titanium alloy that exhibits unique shape memory and superelastic characteristics. Finite element analysis can be a powerful tool in designing medical devices to withstand such a rigorous loading environment.

In the design of hearing instruments it is important to achieve as high gain as possible

without causing oscillation in the device, due to feedback between the microphones and the