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Mechanical Testing System Coupled with an Environmental Chamber for Hydrogels. Team: Charlie Haggart, Gabriel J. Martínez-Díaz, Darcée Nelson, and Michael Piché Client: Weiyuan John Kao, Ph.D. Advisor: Paul Thompson BME 402 Midsemester Presentation 3/7/03. Overview. Problem Statement
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Mechanical Testing System Coupled with an Environmental Chamber for Hydrogels Team: Charlie Haggart, Gabriel J. Martínez-Díaz, DarcéeNelson, and Michael Piché Client: Weiyuan John Kao, Ph.D. Advisor: Paul Thompson BME 402 Midsemester Presentation 3/7/03
Overview • Problem Statement • Background Information • Previous Work • Current Progress • Future Work • Acknowledgements
Problem Statement • To design and build an environmental chamber to be used with a mechanical testing system to observe the tensile and creep properties of hydrogels under varying physiological conditions
Background Information • Hydrogels • Cross-linked polymeric structures • Can absorb water or biological fluids • Properties change with pH and temperature • Applications include drug delivery vessels and wound/burn care
Design Specifications • Mechanical properties of hydrogels must be characterized in physiological conditions (pH = 4-8 and 37 °C) • Interested in tensile and creep properties to understand the behavior of hydrogels in varying conditions
Previous Work: Tensile Testing • Environmental chamber was built to be used with Instron 1000
Previous Work: Creep Testing • Instron 1000 incapable of creep testing • No other commercially available devices exist • Creep chamber was built last semester
Present Work: Tensile Testing • Conducted tensile testing with environmental chamber and Instron 1000 • Environmental chamber met specifications (maintained physiological conditions, compatible with Instron 1000)
Present Work: Tensile Testing • Instron 1000 not sensitive enough to measure tensile properties of hydrogels tested • System may be used for future testing • Different materials (i.e. rat skin)
Present Work: Creep Testing • Problem • Grips were difficult to adjust • Solution • New grips were ordered from McMaster-Carr 1“
Present Work: Creep Testing • Problem • Chamber too small to fit hands into, making sample adjustment difficult • Solution • Modified tensile chamber, in order to be used for tensile AND creep tests
Present Work: Creep Testing Pulley system will be added here Weight stand Bottom grip attached Acrylic cylinder to stabilize LVDT Acrylic cylinder added that forms tight seal with o-ring Chamber positioned onto creep base
Future Work • Modify grips for use in creep testing system • Attach pulley apparatus • Data acquisition • Validation of creep testing system
Acknowledgements • Professor Kao • Paul Thompson • Bill Hagquist, ME Shop • Jeff Schowalter, ECE Dept. • BME Dept.