An Investigation into the use of Strain Rosettes for the Measurement of Propagating Cyclic Strains

Abstract An investigation into the feasibility of using a strain rosette to measure the principal strains and to locate the principal axes for a propagating strain wave is carried out for the particular application of a flexural-gravity wave in sea ice. It is found that the separation of the instrum...

Full description

Bibliographic Details
Published in:Journal of Glaciology
Main Author: Squire, Vernon A.
Format: Article in Journal/Newspaper
Language:English
Published: Cambridge University Press (CUP) 1978
Subjects:
Online Access:http://dx.doi.org/10.1017/s0022143000013952
https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000013952
Description
Summary:Abstract An investigation into the feasibility of using a strain rosette to measure the principal strains and to locate the principal axes for a propagating strain wave is carried out for the particular application of a flexural-gravity wave in sea ice. It is found that the separation of the instruments in the rosette is extremely critical and, for a physically realizable rosette, errors are unavoidable if strain is to be monitored continuously. An alternative approach is proposed employing frequency-domain analysis and in particular a running-power spectral density. The method is demonstrated with data obtained from strainmeters on fast ice in Notre Dame Bay, Newfoundland. Two distinct wave components are found to be present of period 6 s and 13s. and it is shown with 99.9% confidence that they are propagating in different directions.