ISSN: 1945-7553
Page Count: 7

An Analog Control System for an Inverted Torsion Pendulum

Willertz, LE
Senior engineers, Westinghouse Research Laboratories, Pittsburgh,Pa.

Pradhan, AH
Senior engineers, Westinghouse Research Laboratories, Pittsburgh,Pa.

Abstract

An analog system has been designed, constructed, and tested for driving an inverted torsion pendulum used in determining damping and internal friction properties of materials. The system is capable of determining log decrements from the electrical characteristics of the system from 10⁻⁴ to 10⁻¹ at stresses from 10² to 10⁵ psi with the results being plotted directly by an X–Y recorder. Other variables can be plotted on the x axis in addition to stress, such as magnetic field strength, temperature, time, and axial loads to make this a valuable instrument in the field of metallurgical research. Initial results using this system have shown them to compare almost exactly with those obtained using the usual free decay method.

Keywords:
damping, internal friction, analog, torsion pendulum, control

Paper ID: JTE10039J
DOI: 10.1520/JTE10039J
ASTM International is a member of CrossRef.