Greg Sassi

Publication Date


Document Type


First Advisor

Gau, Jenn T.

Degree Name

M.S. (Master of Science)

Legacy Department

Department of Mechanical Engineering


Mechanical engineering; Materials science; Automobiles--Design and construction


Commercially pure titanium foil is a material that has become very useful in fields ranging from the automotive to the medical industry. With the miniaturization trend of technology, the forming abilities of Ti have to be evaluated because it is well known that the formability changes when moving from the macro to micro scale. This study analyzes the equibiaxial portion of the Forming Limit Curve (FLC) of 38 mum thick commercially pure grade 2 titanium with the use of a custom hydraulic bulge apparatus and testing criteria. The hydraulic bulge test creates pure biaxial tension by clamping a flat foil sample to obtain a fixed boundary condition and then applying pressure on one side to promote material deformation. Strain is measured by studying the deformation of a grid of 50 mum in diameter circles that are on top of the thin foil. By testing two different bulge diameters of 2 mm and 5 mm, it is determined that the bulge diameter does not have a great effect on the maximum strains experienced, but that the smaller bulge diameter should be used in an effort to save material. Experimental strain data is compared to LS-Dyna simulations to show that the simulations result in safe, but not necessarily correct, material responses.


Advisors: Jenn T. Gau.||Committee members: John Shelton; Sahar Vahabzadeh.||Includes illustrations.||Includes bibliographical references.


44 pages




Northern Illinois University

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