Wyniki wyszukiwania - Biblioteka Nauki

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Biomechanical characterization of the balloon-expandable slotted tube stents

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Pochrząst M. , Walke W. , Kaczmarek M.

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2009

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tom Vol. 37, nr 2

340-347

EN

Purpose: The aim of the presented work was determination of the biomechanical characteristics of the vascular stent made of stainless steel (Cr-Ni-Mo) and Co-Cr-W-Ni alloy. Additionally, in order to compare obtained results, an experimental analysis of the stent made of stainless steel was carried out. Design/methodology/approach: In order to determine the strength characteristics of the analyzed stent the finite element method was applied. Geometrical model of the vascular stent, which was meshed with the use of the SOLID95 element, was worked out. Selection of the finite element was conditioned by large strains that occur during angioplastic procedure. The established boundary conditions imitated the phenomena during the balloon expansion in real conditions. Findings: The result of the analysis was determination of relationship between equivalent stresses and strains in the individual regions the stent in the function of the diameter’s change (d = 1.20 - 4.00 mm) caused by expanding pressure. Analysis of the obtained results indicates diverse distribution of stresses and strains in the stent depending on the applied biomaterial. Research limitations/implications: The obtained results of the biomechanical analysis of the coronary stent are valuable information for correct design of the geometry and mechanical properties of the applied metallic biomaterials. Strain analysis of the stent indicates that in order to limit a surface reactivity of the stent in blood environment, a deformable surface layer must be applied. Originality/value: Results of the numerical analysis indicate that mechanical properties of the metallic biomaterials used to manufacture the analyzed vascular stent were selected correctly. The correctness of the selection (mechanical properties of the metallic biomaterials) should be confirmed in in vitro tests realized with the use of the coronary angioplasty set.

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Badania własności elektrochemicznych warstw krzemionkowych stosowanych na wyroby medyczne przeznaczone do kontaktu z krwią

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Basiaga M. , Popik P. , Paszenda Z. , Pochrząst M.

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tom R. 89, nr 12

374-377

PL

W pracy zaprezentowano wyniki badań własności elektrochemicznych warstw krzemionkowych wytworzonych na stali Cr-Ni-Mo przeznaczonej do kontaktu z krwią. Badane próbki poddano szeregowi metod obróbki powierzchniowej: szlifowanie, polerowanie elektrolityczne, pasywacja chemiczna, naniesienie warstw krzemionkowych przy wykorzystaniu zanurzeniowej techniki zol-żel. W celu określenia własności elektrochemicznych powłok SiO2 przeprowadzono badania odporności korozyjnej metodami: potencjodynamiczną oraz impedancyjną.

EN

The paper presents the results of the electrochemical properties of silica layers produced on Cr-Ni-Mo steel intended for contact with blood. The samples were subjected to a series of surface preparation methods: grinding, electrolytic polishing, chemical passivation, sol-gel silica coatings by means of dipping. For the evaluation of electrochemical properties of SiO2 layers of corrosion resistance tests were carried out by means of potentiodynamic and impedance methods.

3

Biomechanical analysis of limited-contact plate used for osteosynthesis

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Pochrząst M. , Basiaga M. , Marciniak J. , Kaczmarek M.

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tom Vol. 16, no. 1

99--105

EN

This paper presents the results of numerical analysis aimed at determining the state of stresses and displacements of compression plate used in osteosynthesis of tibia, carried out by applying finite element method using the ANSYS program. The analysis took into account two variants of the osteosynthesis. Variant I included the osteosynthesis in which plate was attached directly to the bone, in variant II, the plate was moved away from the bones by about 5 mm. Biomechanical characteristics of the corrective osteotomy plate–tibia was determined for implants made of Ti-6Al-4V alloy. The boundary conditions adopted for the analysis reflect phenomena occurring in a real system. Based on the results of the analysis relative displacements and reduced stresses in various components were determined as a function of the applied load within the range of F = 500–1500 N. The maximum forces, both variant I and variant II determined during analysis, ensure that the generated stress does not exceed yield strength of the material and compressive strength of the bone, and do not exceed safety movement in the fracture gap. In addition, it was found that the locking of the compressive plate to the bone has a little effect on the distribution of displacements and stresses on the plate–tibia system in the case of a simple fracture.

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Zastosowanie elektrochemicznej spektroskopii impedancyjnej do oceny stopu Ti-6Al-4V ELI stosowanego w ortopedii

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Pochrząst M. , Marciniak J. , Walke W. , Kaczmarek M. , Szewczenko J. , Loska S.

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tom Vol. 14, no. 106-108

149--153