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Document Type

Campus Access

Degree Program

Mechanical Engineering

Degree Type

Master of Science in Mechanical Engineering (M.S.M.E.)

Year Degree Awarded

2012

Month Degree Awarded

February

Keywords

Creep, Non-contact, Computational simulation, FEA, MASC, Stress exponent

Abstract

Currently, various needs from industry, science and national defense strategy demand materials with cutting-edge ultra-high temperature performances. Typical applications of ultra-high temperature materials (UHTMs) are supersonic airplanes, gas turbines and rocket nozzles which usually require continuous service of critical components at temperatures higher than 1600°C. Creep resistance is a critical criterion in designing materials for these applications. Traditional creep characterization methods, however, due to limitations on cost, accuracy and most importantly temperature capability, gradually emerge as a bottleneck.

Since 2004, a group of researchers in the University of Massachusetts, Amherst have been designing a new high temperature characterization scheme that can break through the limits of traditional methods. Their method is based on non-contact creep tests conducted with Electrostatic levitation (ESL) facilities in NASA Marshall Space Flight Center in Huntsville Alabama. The tested sample is levitated in electric field and is heated as well as rotated with specially positioned laser beam. After certain amount of time, the sample deforms under centripetal forces. By comparison of the shape of the deformed sample with results from finite element simulation, creep behavior of the tested material can be characterized.

Based on the same theory, this thesis presents a computational creep characterization method based on non-contact method. A finite element model was built to simulate non-contact creep behavior and results were compared to ESL experiments to determine the creep characteristic. This method was validated both theoretically and numerically and then applied to creep characterization of a promising ultra-high temperature composite from General electric (GE).

First Advisor

Robert W. Hyers

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