A study of the stud-welded vibrating wire strain gage
Dawkins, William Paul
Master of Science
The purpose of this investigation was to determine the variables which affect the stability of a stud-welded vibrating wire strain gage. The lack of previously published information and the nature of the instrument required an origonal design. When undesirable conditions were noted, an attempt has been made to eliminate such conditions through a change in design of gage components or installation techniques. Two basic configurations have been studied, differing in the manner in which wire tension is maintained. Both types were subjected to zero drift observations and calibration tests. The results of these tests indicate that the classic method of wire attachment, that of squeezing the wire ends between a pair of anvils or pins, aggravates the natural tendency of the wire to relax under tension and introduces a drift error which is difficult to predict. The second configuration, developed during the investigation, is similar to that utilized in tuning a piano or violin. Eliminating the deformation of the wire cross section greatly reduces relaxation and hence the error introduced by drift. Both configurations proved to be very accurate and dependable for short term tests.