14 CompositesWorld
DESIGN & TESTING
MARCH 2018
FIG. 4 Screen shots taken from the video gauge images
identify KGR equivalent measurement points (top) compared
to those gathered by the conventional shear gauge (bottom).
Source | Imetrum
In addition, it allows all the rich data currently not captured to be
recorded for in-depth analysis (Fig. 4, at left).
A total of 18 points were identified and measured (Fig. 5, p. 15)
yielding the following data:
• Shear strains between points 16 and 17 provide the
basic functionality of the KGR extensometer.
• Tracking points 2 and 16 and points 3 and 17 allow
rotation of the sample to be determined.
• Tracking points 3; 11 and 17; and 4, 12 and 17 allow the
shear and tensile strains in the arms of the test fixture
to be captured.
• Tracking points 5 and 6; 9 and 10; and 13 and 14 allows
the strain in the adhesive to be measured directly.
• Tracking the displacements of points 2 and 3 or 16
and 17 allows any change in adhesive thickness to be
captured.
e various relationships between these points can be tracked in
real-time during the test and/or stored for post-process analysis.