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Full-Text Articles in Engineering Science and Materials

Experimental Validation For The Theory Of Blisters’ Instabilities, Hongtian Zhu Jan 2018

Experimental Validation For The Theory Of Blisters’ Instabilities, Hongtian Zhu

Mechanical Engineering Graduate Theses & Dissertations

Blister formation is a universal problem that can be witnessed within a wide range of contents. It is first documented as a side effect of syringomyelia and other diseases. Later on, the forming of blisters are also observed during the cell apoptosis, which leads to the hypothesis that it could have some intricate relationships with the death of living organisms. Other than biological problems, blister forming is also a common phenomenon in thin film technologies. Therefore, the research in the forming of blisters is essential and critical in both engineering and science fields.

In this thesis, we study the problem ...


Lamb Waves With Conical Dispersion At Zero Wavenumber, David M. Stobbe Jan 2018

Lamb Waves With Conical Dispersion At Zero Wavenumber, David M. Stobbe

Mechanical Engineering Graduate Theses & Dissertations

Lamb waves are guided elastic waves in plates. These waves are dispersive, with the frequency and wavenumber related by the well-known Rayleigh-Lamb equation. Generally, at zero wavenumber the dispersion curves are parabolic and the waves are non-propagating thickness resonances. For distinct values of Poisson’s ratio, however, degeneracy can occur between thickness resonance modes. At these coincidence frequencies the dispersion curves become linear and in a three-dimensional representation the dispersion surface is shaped like a cone. This behavior is referred to as conical dispersion. Waves excited at coincidence frequencies maintain the infinite phase velocity associated with thickness resonances but transport ...


Roll-To-Roll Atomic Layer Deposition Of Ultrabarriers, Alexander Yersak Jan 2016

Roll-To-Roll Atomic Layer Deposition Of Ultrabarriers, Alexander Yersak

Mechanical Engineering Graduate Theses & Dissertations

Atomic layer deposition (ALD) is a bottom-up, gas phase, thin film deposition technique based on sequential, self-limiting binary surface reactions. The precise sub-nanometer film thickness control and conformal nature of this process have led to various commercial applications of ALD. However, ALD films are most commonly deposited in batch processes at low pressures, which raises throughput and/or cost concerns for many otherwise promising applications. This problem can be solved by spatial ALD (S-ALD) which is a version of the ALD technique where the precursors are separated in space rather than time. We have demonstrated the first atmospheric pressure roll-to-roll ...


Thermomechanics Of Shape Memory Polymers And Composites, Qi Ge Jan 2012

Thermomechanics Of Shape Memory Polymers And Composites, Qi Ge

Mechanical Engineering Graduate Theses & Dissertations

This dissertation presents studies with a combination of experiment, theory, and simulation on a broad range of polymeric material systems (both established and emerging), that exhibit the shape memory (SM) effect. The goals of the studies are to understand complex thermomechanical behaviors of shape memory polymers (SMPs), develop constitutive models to describe the behaviors and use the developed models to advance the development and deployment of SMPs. The general approach used in the studies is independent of the material system and consists of: i) sample fabrication and thermomechanical experiments including dynamic mechanical analysis (DMA), stress-strain behaviors and thermal strain tests ...