Author(s)

Juan Roche

Date Approved

8-21-2012

Document Type

Thesis

Degree Name

M.S. Engineering

Department

Mechanical Engineering

College

Henry M. Rowan College of Engineering

First Advisor

Von Lockette, Paris

Subject(s)

Elastomers;Magnetization

Disciplines

Mechanical Engineering

Abstract

This thesis studies the magnetic and mechanical behavior of magnetorheological elastomers (MREs) based on four possible permutations defined along particle alignment (Aligned and Unaligned) and magnetization (Hard- or Soft-magnetic) pairs. These pairs designations yield classes A-H, U-H, A-S and U-S. The last two classes comprise traditional MREs. Samples were fabricated by mixing DOW HS II silicone elastomer compound and 30% by volume of either nominally 40-micron M-type barium hexaferrite (BaM) or 325-mesh iron (Fe) particles cured with or without the presence of a magnetic field. Magnetization and density measurements were employed to help confirm fabrication of the four distinct classes. Results of magnetization measurements suggest that the goal of defining and fabricating the four classes was functionally achieved. The motivating for this project stems from the notion that in soft-magnetic particles (i.e. Fe), behavior is driven by local demagnetizing effects while hard-magnetic particles (i.e. BaM) have a preferred magnetic axis and therefore generate magnetic torques at the particle level. The larger thesis seeks to define, model, and differentiate the nature of the magnetic torque response across all four classes.

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