3-D Digital Image Correlation Test (Nsa3)
Full-field Surface Displacement
|An initial compression test of a composite stub wing
cover panel with three stiffeners and a center notch was performed at NASA Langley
Research Center. The dimensions of the Kevlar-stitched, resin-film infused, graphite-epoxy
panel were 1.06 m long, 0.482 m wide, and 12 mm thick with a 183 mm notch. Since strain
gages covered most of the skin side of the panel, the pattern was applied around the gages
and lead wires, as shown in the following figure.
Breaking the surface into five disjoint regions resulted in acquiring five separate data sets that had to be recombined into a single data set. The maximum measured displacement in the W (out-of-plane) field was 2.765 mm, the Vmax (vertical) displacement was 3.555 mm, and the Umax (horizontal) displacement was 0.701 mm. An animated GIF is provided to illustrate the panel deformation. Out-of-plane buckling in the Z direction can be clearly seen in the panel profile during the test. A contour map displayed on the profile surface illustrates the deformation in the X direction.
The VIC-3D data for out-of-plane displacement was compared to DCDT measurements for a single point on the panel. The DCDT was located on the web of the central stiffener, approximately 46 mm above the notch centerline, and the VIC-3D measurements were obtained at the same position on the opposite side of the panel. The data from both systems was in good agreement.