Digital Image Correlation (DIC) is a technique for optically acquiring full-field
measurements of the displacement and deformation of a surface. This is achieved
by observing the surface as it deforms, typically using one or more conventional
monochrome digital cameras, and comparing the surface’s deformed and
undeformed states using optical tracking.
The Defence Technology Agency’s Applied Vehicle Systems group has now
developed an in-house DIC system. The wide array of variables that determine the
measurement precision achievable when using DIC makes it difficult to identify a
specific metric quantifying this system’s accuracy. However, a conservative estimate
is that deformation measurements can be obtained with a precision of 1000
microstrain or better in most cases. Greater precision may be achievable in a
number of instances, particularly for cases involving smooth strain fields where
significant smoothing can be applied to the measured displacements without
detrimentally affecting the results.
This system is now available to enhance the Applied Vehicle Systems group’s
structural analysis toolset, providing a full-field strain measurement capability for
New Zealand Defence Force platforms. In contrast to commercial DIC systems, this
in-house system can be fully customised and adapted to suit individual New Zealand
Defence Force requirements.
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