Zhen Yin

Abstract

The pumping potential (PP) of a structure is defined as the ratio of the relative volume change to a relative input stroke. It is introduced to evaluate the volumetric efficiency of a pump. The value of the PP is related to the geometric characteristics and the material properties of the pump structure. A single-layer hyperbolic shell-of-revolution flexible matrix composite (FMC) structure was investigated by Ghoneim and Noor. When under torsion, the rotation of the hyperbolic shell structure causes the throat diameter and the characteristic length to simultaneously decrease, rendering a substantial volumetric decrease and consequently a high PP. Some fibrous composite materials can have negative Effective Poisson's ratio. One of their most distinguished characteristics is that they laterally expand under stretching and contract under compression, while for an isotropic material having positive Poisson's ratio, it expands under compression and contracts under stretching. Therefore, when subjected to axial loading, the relative volume change of a structure made of negative Poisson's ratio materials would be larger than the corresponding one made of a conventional material. When applied to a pump structure, this characteristic (negative effective Poisson's ratio) is expected to increase the pumping potential due to the larger relative volume change. For FMC laminates, when fiber orientation angles are properly set up, a high negative effective Poisson's ratio can be obtained. As a result, structures made of these FMC laminates could engender a larger PP. Our work attempts to improve upon the PP of the single-layer hyperbolic shell structure by using multi-layer FMC materials with negative effective Poisson's ratio. The study is conducted both analytically and experimentally. The PP of FMC, with negative effective Poisson's ratio, cylindrical and hyperboloid structures using built-in Matlab codes as well as the ANSYS finite element package, is evaluated. In addition, hyperboloid FMC structures are built and tested. The analytical and experimental PP are compared. The work concludes that the negative Poisson's ratio has considerably improved the PP of the hyperboloid structure.

Library of Congress Subject Headings

Pumping machinery--Fluid dynamics; Fibrous composites--Mechanical properties; Poisson's equation

Publication Date

6-2014

Document Type

Thesis

Student Type

Graduate

Degree Name

Mechanical Engineering (MS)

Department, Program, or Center

Mechanical Engineering (KGCOE)

Advisor

Hany Ghoneim

Advisor/Committee Member

Stephen Boedo

Advisor/Committee Member

Benjamin Varela

Comments

Physical copy available from RIT's Wallace Library at TJ900 .Y46 2014

Campus

RIT – Main Campus

Plan Codes

MECE-MS

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