Engineering Science and Materials Commons^™

Mechanics Of Pure Bending And Eccentric Buckling In High-Strain Composite Structures, Jimesh D. Bhagatji, Oleksandr G. Kravchenko, Sharanabasaweshwara Asundi

Mechanical & Aerospace Engineering Faculty Publications

To maximize the capabilities of nano- and micro-class satellites, which are limited by their size, weight, and power, advancements in deployable mechanisms with a high deployable surface area to packaging volume ratio are necessary. Without progress in understanding the mechanics of high-strain materials and structures, the development of compact deployable mechanisms for this class of satellites would be difficult. This paper presents fabrication, experimental testing, and progressive failure modeling to study the deformation of an ultra-thin composite beam. The research study examines the deformation modes of a post-deployed boom under repetitive pure bending loads using a four-point bending setup and …

Strain-Enhanced Coherent Exciton-Polaron States In 1d Phthalocyanine Crystalline Thin Films, Libin Liang

Graduate College Dissertations and Theses

Organic semiconductors are at the forefront of materials research, due to their desired electric and mechanical properties. They offer the unique opportunity to modify material properties during synthesis process, opening an avenue to the development of novel flexible and wearable electronic and photonic devices.Molecular excitons are of importance in organic semiconductor properties. While majority of research studies are centered on achieving good control of amorphous or polycrystalline thin film properties, the static disorder effect leads to poor device performance when compared to inorganic semiconductors with superior crystalline ordering. On the other hand, the macroscopic molecular long-range ordering can enhance device …

Experimental And Field Evaluation Of Frp Pedestrian Bridge Decks, Kalrav Singh Tomer

Graduate Theses, Dissertations, and Problem Reports

Traditional materials such as steel, timber, and concrete have continued to dominate their usage in civil infrastructure. They offer great advantages like strength and stiffness but at the same time they pose major issues in terms of durability and maintenance. Fiber reinforced polymer (FRP) exhibits outstanding properties like lightness, excellent corrosion and wear resistance along with superior thermo-mechanical properties. Glass FRPs (GFRPs) have emerged as one of the best alternatives in the field of civil infrastructure. It has been more than four decades since fiber reinforced polymer (FRP) composites have gained notable applications in civil infrastructure industry. However, FRPs have …

Disturbed Cyclical Stretch Of Endothelial Cells Promotes Nuclear Expression Of The Pro-Atherogenic Transcription Factor Nf-Kb, Ryan M. Pedrigi, Konstantinos I. Papadimitriou, Avinash Kondiboyina, Sukhjinder Sidhu, James Chau, Miten B. Patel, Daniel C. Baeriswyl, Emmanuel M. Drakakis, Rob Krams

Department of Mechanical and Materials Engineering: Faculty Publications

Exposure of endothelial cells to low and multidirectional blood flow is known to promote a pro-atherogenic phenotype. The mechanics of the vessel wall is another important mechano-stimulus within the endothelial cell environment, but no study has examined whether changes in the magnitude and direction of cell stretch can be pro-atherogenic. Herein, we developed a custom cell stretching device to replicate the in vivo stretch environment of the endothelial cell and examined whether low and multidirectional stretch promote nuclear translocation of NF-kB. A fluid–structure interaction model of the device demonstrated a nearly uniform strain within the region of cell attachment and …

Investigation Of Electrical Defects Arising From Excessive Sidewall Force And Excessive Tensile Strain On Power Cables, Darren Mcconnon, Joseph Kearney, Tom Looby, James O'Shaughnessy

Conference papers

The study includes a comprehensive review of the existing literature and guidelines regarding the effects of sidewall force and tensile strain on power cables during installation. The most appropriate diagnostic test methods required to analyse these effects are also assessed. The results of tests and analysis of the existing literature are then combined in an attempt to determine a realistic basis for guidelines and recommendations relevant to cable installation forces.

Electron Correlation Effects In Strained Dual-Layer Graphene Systems, Peter Karl Harnish

Graduate College Dissertations and Theses

In low dimensional systems, electron correlation effects can often be enhanced. This can be vital since these effects not only play an important role in the study of many-electron physics, but are also useful in designing new materials for various applications. Since its isolation from graphite in 2004, graphene, a two dimensional sheet of carbon atoms, has drawn considerable interest due to its remarkable properties. In the past few years, research has moved on from single to bi-, dual- and multi-layer graphene systems, each displaying their own multitudes of intriguing properties. In particular, multi-layer systems that are electronically decoupled, but …

Compression Testing And Failure Modes Of Steel-Concrete Composite (Sc) Structures For Nuclear Containment, Patrick Michael Wanamaker, Amit H. Varma

The Summer Undergraduate Research Fellowship (SURF) Symposium

Although being able to provide much cleaner power than burning coal and other fossil fuels, nuclear power plants are still a tough sell to the general public due to their history of being spontaneously dangerous. The containment structures surrounding these nuclear plants, however, can play a huge role in reducing the risks associated with them. Relatively new designs for these containment assemblies, known as SC (steel-concrete composite) structures, aim to increase the strength and durability of the containment facilities while keeping costs down. By varying the spacing between shear studs, the ratio of concrete to steel, and the ratio of …

A Resistance Based Structural Health Monitoring System For Composite Structure Applications, Dennis N. Boettcher

Master's Theses

This research effort explored the possibility of using interwoven conductive and nonconductive fibers in a composite laminate for structural health monitoring (SHM). Traditional SHM systems utilize fiber optics, piezoelectrics, or detect defects by nondestructive test methods by use of sonar graphs or x-rays. However, these approaches are often expensive, time consuming and complicated.

The primary objective of this research was to apply a resistance based method of structural health monitoring to a composite structure to determine structural integrity and presence of defects.

The conductive properties of fiber such as carbon, copper, or constantan - a copper-nickel alloy - can be …

Regional Mechanical Properties And Stress Analysis Of The Human Anterior Lens Capsule, Ryan M. Pedrigi, G. David, J. Dziezyc, J. D. Humphrey

Department of Mechanical and Materials Engineering: Faculty Publications

The lens capsule of the eye functions, in part, as a deformable support through which the ciliary body applies tractions that can alter lens curvature and corresponding refractive power during the process of accommodation. Although it has long been recognized that characterization of the mechanical properties of the lens capsule is fundamental to understanding this physiologic process as well as clinical interventions, prior data have been limited by one-dimensional testing of excised specimens despite the existence of multiaxial loading in vivo. In this paper, we employ a novel experimental approach to study in situ the regional, multiaxial mechanical behavior of …