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Materials Science and Engineering

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University of Massachusetts Amherst

Buckling

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Full-Text Articles in Engineering

Euplectella Aspergillum’S Natural Lattice Structure For Structural Design & Stability Landscape Of Thin Cylindrical Shells With Dimple Imperfections, Zoe Y. Sloane Mar 2022

Euplectella Aspergillum’S Natural Lattice Structure For Structural Design & Stability Landscape Of Thin Cylindrical Shells With Dimple Imperfections, Zoe Y. Sloane

Masters Theses

The first portion of this thesis assesses the structural application of a bracing design inspired by the deep-sea sponge, Euplectella Aspergillum. Many studies have investigated the natural strength found in the unique skeletal structure of this species. The braced design inspired by the sponge features square frames with two sets of cross-braces that are offset from the corners of each frame, creating a pattern of open and closed cells. This study reports the results of multiple Finite Element Analysis (FEA) computations that compare the described bracing pattern to a more common bracing design used in structural design. The designs …


Post-Wrinkling Behaviors In Layered Elastic Polymers, Anesia D. Auguste Jul 2016

Post-Wrinkling Behaviors In Layered Elastic Polymers, Anesia D. Auguste

Doctoral Dissertations

Surface instabilities include a variety of different modes such as wrinkles, folds, and creases. Such surface instabilities have been used in numerous contexts including changing the wetting, optical, and mechanical properties of different material surfaces for applications in flexible electronics, tissue engineering and biosensors. Interesting surface morphologies can arise due to differences in pre-strain, stiffness, and thickness between the film and substrate; however, the effects of these differences are not well understood. We have developed an experimental system, complemented by finite element simulations, to systematically vary the pre-stretch of the substrate, modulus contrast and thickness contrast to study the transitions …


Effect Of Processing History And Material Properties On The Growth Of Wrinkle Amplitude, Yu-Cheng Chen Nov 2015

Effect Of Processing History And Material Properties On The Growth Of Wrinkle Amplitude, Yu-Cheng Chen

Doctoral Dissertations

Wrinkling has been employed by many organisms to form unique topography, such as fingerprints, gut villi, and surface of flower petal cells. The wavy wrinkle structure provides friction enhancement, surface area increase, optical, and wetting properties improvement. Inspired by Nature, scientists have created wrinkles synthetically and proposed numerous uses for them. However, wrinkling surfaces encounters limitations on achieving massive area and high amplitude-to-wavelength ratio (aspect ratio). The three phase contact line wrinkling technique creates well-defined wrinkles in a continuous fashion, and has great potential to scale-up for massive production. In addition to the velocity dependent adhesion force, we find the …


Studies On The Wrinkling Of Thin Polymer Films Floating On Liquid, Kamil B. Toga Nov 2014

Studies On The Wrinkling Of Thin Polymer Films Floating On Liquid, Kamil B. Toga

Doctoral Dissertations

This dissertation aims to broaden our understanding on wrinkling instabilities occurring on floating polymeric sheets, and tries to establish innovative methods that exploit these patterns in studies on material behavior and interfacial phenomena. We will address three major topics in this thesis including, i) characterization of the conditions required to buckle an annular disc, ii) characterization of wrinkles occurring around a droplet/bubble placed on a membrane that is kept taut at the liquid-air interface, and iii) using wrinkling patterns as a probe to understand the interfacial behavior and dynamics of ultrathin films. The first project in this thesis is about …