Mechanical Engineering ETDs

Publication Date



The primary purpose of this thesis was the solution of several special problems relating to the establishment, adjustment, and measurement of small elastic curvatures and the associated strains in a metal shaft. The solution of these problems was an important link in the development of a new type of seismometer for measuring extremely long period with vibrations (up to 60 seconds). To achieve the sensitivity and long natural period of vibration required for accurate measurements of long-period waves, the seismometer employs a seismic mass which is suspended on an air film and constrained to follow an essentially horizontal guide rod. The guide rod, which was originally straight, is bowed elastically through use of a straining frame to form a plane curve which is concave upward. this combination of guidance and support forms a lightly damped gravity pendulum in which the seismic mass always seeks the lowest point on the curve. The natural period of this pendulum must be adjustable between the limits of 20 and 200 seconds to allow both ease of setup and high-fidelity performance. This is equivalent to saying that the guide-shaft radius of curvature must be adjustable from about 327 feet up to about 32,700 feet.

Degree Name

Mechanical Engineering

Level of Degree


Department Name

Mechanical Engineering

First Committee Member (Chair)

Richard Charles Dove

Second Committee Member

Frederick Dsuin Ju

Third Committee Member

Charles Theron Grace

Document Type