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Time‐lapse speckle interferometry
Author(s) -
Schmitt Douglas R.,
Hunt Roger W.
Publication year - 1999
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/1999gl008350
Subject(s) - displacement (psychology) , drilling , geology , interferometry , deformation (meteorology) , stress (linguistics) , transient (computer programming) , speckle pattern , compression (physics) , optics , materials science , physics , computer science , psychology , linguistics , oceanography , philosophy , metallurgy , composite material , psychotherapist , operating system
An experimental technique for recording the time dependent evolution of micron‐scale three dimensional displacement fields is developed. In the method, each frame of a motion‐picture consists of a map of the relative wrapped phase, displayed as a fringe pattern, between two images of the appropriately illuminated object acquired at different times. In an illustrative demonstration, stress‐relief displacements are obtained by drilling an acrylic block subject to uniaxial compression. The resulting fringe motion‐picture displays three time dependent regimes to the resulting displacement field: 1) a transient axi‐symmetric thermal expansion centered on the stress relief hole due to drilling, 2) elastic stress‐relief fringes at short times after drilling, and 3) continued plastic deformation over long time periods after drilling. The method will have many applications at the laboratory scale and is particularly well suited to physical modeling of geodynamic processes.