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FRACTURE TOUGHNESS OF A HYPERELASTIC MATERIAL DURING SURGICAL CUTTING
Title
FRACTURE TOUGHNESS OF A HYPERELASTIC MATERIAL DURING SURGICAL CUTTING.
Creator
Smith, Kevin, Gordon, Ali, University of Central Florida
Abstract / Description
Despite being one of the most important organs of vertebrates, the material properties of skin are also one of the most poorly understood. In the field of designing medical devices and surgical tools there are significant advantages to having a model that describes the interaction of forces between a blade tip and skin during surgical cutting. In general, skin can best be described as a composite layer consisting of a viscoelastic dermis with interwoven collagen and elastin fibers beneath a...
Show moreDespite being one of the most important organs of vertebrates, the material properties of skin are also one of the most poorly understood. In the field of designing medical devices and surgical tools there are significant advantages to having a model that describes the interaction of forces between a blade tip and skin during surgical cutting. In general, skin can best be described as a composite layer consisting of a viscoelastic dermis with interwoven collagen and elastin fibers beneath a superficial epidermis. The purpose of this research is to study the fracture toughness of porcine skin during practical cutting applications, the behavior of skin under quasi-static loads, and viscoelastic behavior of skin during stress relaxation. To fully describe the mechanics of skin in this model tensile test are conducted to determine the material properties of skin. The fracture toughness of the material is calculated by measuring the energy release rate of the material during required during cutting with Number 11 scalpel blade with a tip radius of 12[mu]m. These results are then compared to a finite element analysis with a debonding interface and a Mooney-Rivlin hyperelastic material model with viscoelastic relaxation in an effort to predict the loads required by tools during surgical applications. The main outcome of this research is the development of a testing protocol and material model of skin that can be used in finite element simulations of uniaxial loads and surgical cutting.
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Date Issued
2013
Identifier
CFH0004530, ucf:45191
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFH0004530
VIBRATIONAL AND MECHANICAL PROPERTIES OF 10 MOL % SC2O3-1 MOL % CEO2- ZRO2 ELECTROLYTE CERAMICS FOR SOLID OXIDE FUEL CELLS
Title
VIBRATIONAL AND MECHANICAL PROPERTIES OF 10 MOL % SC2O3-1 MOL % CEO2- ZRO2 ELECTROLYTE CERAMICS FOR SOLID OXIDE FUEL CELLS.
Creator
Lukich, Svetlana, Orlovskaya, Nina, University of Central Florida
Abstract / Description
Solid Oxide Fuel Cells (SOFCs) are emerging as a potential breakthrough energy conversion technology for clean and efficient production of electricity and heat from hydrogen and hydro-carbon fuels. Sc0.1Ce0.01ZrO2 electrolytes for Solid Oxide Fuel Cells are very promising materials because their high ionic conductivity in the intermediate temperature range 700oC-800oC. The vibration response of cubic and rhombohedral (β) 10 mol%Sc2O3 - 1 mol%CeO2 - ZrO2 (Sc0.1Ce0.01ZrO2 ) both at room...
Show moreSolid Oxide Fuel Cells (SOFCs) are emerging as a potential breakthrough energy conversion technology for clean and efficient production of electricity and heat from hydrogen and hydro-carbon fuels. Sc0.1Ce0.01ZrO2 electrolytes for Solid Oxide Fuel Cells are very promising materials because their high ionic conductivity in the intermediate temperature range 700oC-800oC. The vibration response of cubic and rhombohedral (β) 10 mol%Sc2O3 - 1 mol%CeO2 - ZrO2 (Sc0.1Ce0.01ZrO2 ) both at room and high-temperatures is reported. The in-situ heating experiments and ex-situ indentation experiments were performed to characterize the vibrational behavior of these important materials. A temperature and stress-assisted phase transition from cubic to rhombohedral phase was detected during in-situ Raman spectroscopy experiments. While heating and indentation experiments performed separately did not cause the transition of the cubic phase into the rhombohedral structure under the performed experimental conditions and only broadened or strained peaks of the cubic phase could be detected, the heating of the indented (strained) surface leaded to the formation of the rhombohedral Sc0.1Ce0.01ZrO2. Both temperature range and strained zone were estimated by in situ heating and 2D mapping, where a formation of rhombohedral or retention of cubic phase has been promoted. The mechanical properties, such as Young's modulus, Vickers hardness, indentation fracture resistance, room and high temperature four point bending strength and SEVNB fracture toughness along with the stress – strain deformation behavior in compression, of 10 mol% Sc2O3 – 1 mol % CeO2 - ZrO2 (ScCeZrO2) ceramics have been studied. The chosen composition of the ScCeZrO2 has very high ionic conductivity and, therefore, is very promising oxygen ion conducting electrolyte for the intermediate temperature Solid Oxide Fuel Cells. Therefore, its mechanical behavior is of importance and is presented in this study.
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Date Issued
2009
Identifier
CFE0002914, ucf:52845
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0002914