Search results for "finite element analysis"
showing 10 items of 98 documents
Virtual simulation of an osseointegrated trans-humeral prosthesis: A falling scenario
2018
Abstract Introduction Traditional prosthetic solutions expose the amputee to numerous problems that limit his ability to safely perform the normal activities of daily life. In order to eliminate the problems related to the use of the traditional prosthesis with socket, a new technique was developed for fixing the prosthesis to the amputees based on the principle of osseointegration. The aim of this paper is to study and analyze the stress distribution on the interface between a trans-humeral osseointegrated prosthetic implant and the residual bone, identifying the most stressed areas and thus foreseeing possible failure phenomena of the entire prosthetic system and, after, to compare the st…
Flying laser spot thermography for the inspection of aerospace grade Fibre Metal Laminates
2017
This work analyses a Non Destructive Testing approach for the detection of interlayer disbonds in aerospace grade Fibre Metal Laminates (FMLs). The NDT setup consists of a continuous laser, focused and moved over the material surface, while an IR thermal camera acquires its thermal footprint. A numerical model of the NDT setup is presented, where the material thermal response is analysed to evaluate the features of the defects signatures. In particular, the response from various types of FMLs is evaluated.
Experimental and numerical evaluation of sandwich composite structures
2004
The main problem working with sandwich composite structures is their intrinsic anisotropy and non-homogeneity that does not allow their correct modelling. Nowadays the available data on mechanical properties of complex structures, necessary to allow a correct and reliable design, are not sufficient. The aim of the present work is to extend the knowledge of mechanical properties both on single components and on complete structures, focusing on the effects induced by different kind of skin arrangements (Kevlar, glass and carbon fibres). Compressive, shear and flexural tests were performed for a complete static mechanical characterisation of the sandwich structure both on each single component…
Essential Measurements for Finite Element Simulations of Magnetostrictive Materials
2018
We discuss which magnetoelastic material properties are essential to measure in order to model magnetostrictive materials in finite element simulations. We show knowing the magnetic constitutive relation is sufficient, if the elastic behavior without magnetic field is known a priori. We neglect hysteresis, and our starting point is to express the effect of mechanical deformation on the magnetic constitutive relation with a small strain tensor and magnetic flux density. It follows that the (energetic) state of a magnetostrictive material is independent of its history. Then, a certain choice of history allows us to keep magnetism and elasticity distinct. We demonstrate with open source softwa…
Modeling Right Ventricle Failure After Continuous Flow Left Ventricular Assist Device: A Biventricular Finite-Element and Lumped-Parameter Analysis
2017
The risk of right ventricle (RV) failure remains a major contraindication for continuous-flow left ventricular assist device (CF-LVAD) implantation in patients with heart failure. It is therefore critical to identify the patients who will benefit from early intervention to avoid adverse outcomes. We sought to advance the computational modeling description of the mechanisms underlying RV failure in LVAD-supported patients. RV failure was studied by computational modeling of hemodynamic and cardiac mechanics using lumped-parameter and biventricular finite element (FE) analysis. Findings were validated by comparison of bi-dimensional speckle-tracking echocardiographic strain assessment of the …
Simulation study of transcatheter heart valve implantation in patients with stenotic bicuspid aortic valve
2019
Bicuspid aortic valve (BAV) anatomy has routinely been considered an exclusion in the setting of transcatheter aortic valve implantation (TAVI) because of the large dimension of the aortic annulus having a more calcified, bulky, and irregular shape. The study aims to develop a patient-specific computational framework to virtually simulate TAVI in stenotic BAV patients using the Edwards SAPIEN 3 valve (S3) and its improved version SAPIEN 3 Ultra and quantify stent frame deformity as well as the severity of paravalvular leakage (PVL). Specifically, the aortic root anatomy of n.9 BAV patients who underwent TAVI was reconstructed from pre-operative CT imaging. Crimping and deployment of S3 fram…
Short-Term Precision Error of Bone Strain Index, a New DXA-Based Finite Element Analysis Software for Assessing Hip Strength
2020
Abstract Bone Strain Index (BSI) is a new finite element analysis tool applied to hip dual energy X-ray absorptiometry scans. The aim of this study was to assess the short-term precision error of BSI on the proximal femur, both on a phantom and patients. The International Society for Clinical Densitometry guidelines were followed for short-term precision error assessment. Dual energy X-ray absorptiometry measurements were performed on an anthropomorphic femur phantom that was scanned twice for 30 times, for a total of 60 scans. For the in vivo part, 30 subjects were scanned twice. BSI precision error was compared to that of bone mineral density (BMD). Both for the phantom and the in vivo st…
Design av en offshore gangbru i fiberarmert polymer
2018
Masteroppgave bygg BYG508 - Universitetet i Agder 2018 Innovation and development are essential for a market in demand of faster, lighter and stronger solutions. As a material with high strength to weight ratio, and good possibilities of being premade, fiber reinforced polymers can meet those requirements. However, it has yet to challenge concrete, steel and aluminum as a structural material. This is the underlying challenge for the problem statement of this assignment, to construct an offshore gangway using fiber reinforced polymers. The design concept is based on existing steel and aluminum constructions within the size range of 25- 30m fully extended. To solve the problem and answer the …
Static strength and fatigue life of optimized hybrid single lap aluminum–CFRP structural joints
2017
Hybrid bolted/bonded joints are used to assemble structural components, commonly made by carbon fiber reinforced plastics (CFRP), with aluminum frames. Hence, they have become common solutions in a number of modern structural applications in the industrial fields, as well as civil constructions. Unfortunately, due to the lack of understanding of the relationships between the multiple parameters of influence that characterize their mechanical performance, only limited improvement have been achieved so far over classical bonding approaches, in terms of static and fatigue strength. As a result, further studies are needed in order to better exploit the potential of hybrid bolted/bonded joints a…
Engineering the crack path in lattice cellular materials through bio-inspired micro-structural alterations
2019
Abstract A computational study on the fracture behaviour of bio-inspired finite-size lattice configurations is performed in this work. The study draws inspiration from recent investigations aimed at increasing the fracture energy of some materials through small modifications of their microstructure. The main question here is whether it is possible, to some extent, to engineer the crack path in metallic cellular materials through such small micro-structural modifications and how to quantify the effect of alternative strategies. Nature provides several examples of strategies used to delay or arrest damage and crack propagation. One striking example is given by the micro-architecture of severa…