Document Type

Thesis - Open Access

Award Date

1963

Degree Name

Master of Science (MS)

Department / School

Mechanical Engineering

Abstract

When designing any kind of structure or machine for high temperature operation, the engineer has to consider the effects of creep. In steam and gas turbines, for example, the rotor blades are subjected to high stresses by centrifugal force and to elevated temperatures by high pressure steam or hot gases. The combination of high stress and temperature causes a plastic deformation in the blades. This deformation, known as creep, occurs in all metals under the appropriate temperature and stress conditions, though some metals are more resistant to it than others. It is practically undesirable to employ a design so low that no creep will occur; therefore, it must be accounted for in the design of the structure. The creep of a material can be accurately measured in a testing machine, but creep tests cannot be conducted for a length of time corresponding to the life for which a part is usually designed. The rate at which a material creeps over a certain test period is determined in the creep test; and, by the use of empirical relationships, this creep rate can be employed to deduce what the creep will be at the end of a desired time interval. The purpose of this project was to install a creep-rate testing machine in the Mechanical Engineering Research Laboratory at South Dakota State College, and to determine its operating characteristics by conducting tests on a material with known creep properties.

Library of Congress Subject Headings

Metals -- Creep
Metals -- Testing

Description

Includes bibliographical references

Format

application/pdf

Number of Pages

58

Publisher

South Dakota State University

Download

Share

COinS