Title page for ETD etd-08242011-181306


Type of Document Master's Thesis
Author Siuta, Chase Michael
URN etd-08242011-181306
Title Measuring Material Properties of Proton Exchange Membranes using Pressure Loaded Blister Testing and Digital Image Correlation
Degree Master of Science
Department Engineering Science and Mechanics
Advisory Committee
Advisor Name Title
Case, Scott W. Committee Chair
Dillard, David A. Committee Member
Ellis, Michael W. Committee Member
Li, Yongqiang Committee Member
Keywords
  • biaxial strength
  • pressure-loaded blister test
  • proton exchange membrane
  • digital image correlation
  • hydrocarbon membrane
  • PFCB
  • linear damage accumulation
Date of Defense 2011-08-11
Availability unrestricted
Abstract
The strength and durability of proton exchange membranes for use in fuel cells has received much attention recently due to the increased push for sustainable alternatives to the internal combustion engine. To be viable, these alternatives must have comparable lifetimes and power outputs to the internal combustion engines they replace. Chemical degradation was once viewed as the most common culprit of early fuel cell failure, but as membranes and catalysts improved, mechanical failure became an important factor. As a result, fundamental research on the mechanically-induced failure mechanisms of fuel cell membranes, coupled with development and processing of less expensive membranes, has become an important topic. The use of the blister test geometry, along with digital image correlation of the deformed shape, creates a self-contained analysis tool useful for measuring the biaxial strength of membranes. In this work, blister tests are used to measure biaxial stress and strain for fuel cell membranes subjected to ramped pressure loading to form stress-strain curves that indicate the onset of yielding under biaxial stress conditions. Stress-life curves are developed experimentally for Gore-Select® series 57 members using data collected under constant pressure conditions. These results are used to predict blister failure under ramped and fatigue loadings. A newly implemented hydrocarbon membrane system is evaluated with constant-pressure-to-leak blister testing. Improved strength following an isothermal hold at 100°C (pretreatment) is shown to occur. Ramped pressure testing indicates that the material after the pretreatment is stiffer and has a higher yield stress than the material before treatment. Morphological and constitutive characterization indicated differences in the materials that are consistent with the improved performance.
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