Скачать или смотреть Compression test of a soda can for buckling analysis using the TestDIC system in Istra4D V4.11

In this application video, a 3-cam (5 Mpx) TestDIC system is used to analyse the buckling of a soda can undergoing a compression test.
The TestDIC is a fixed setup system whereby the cameras are permanently mounted, and the lenses are fixed in both focus and aperture. This removes the needs to perform any adjustment of the camer and/or lenses. It also relinquishes the need to calibrate the projection of the test setup. Two laser pointers are used to aid the user in adjusting the correct distance-to-object (DtO). At the point of intersection between the two laser pointers, the correct distance and point of focus has been set.
In the measurement, the acquisition speed/camera frame rate of 15 Hz is selected. The recording procedure is used, from an available template, whereby every 5th image is saved at the frame rate.
After acquisition of the measurement images, the correlation evaluation is performed whereby the central camera is selected to be the reference camera, known as the Central Reference Camera Perspective (CRCP). This approach defines the facet/subset generation on the camera with the lowest stereo angle, reducing perspective distortion, and maximizing both in-plane sharpness and out-of-plane depth-of-field (DoF). It also improves measurement accuracy by 30%, as opposed to using a 2-camera setup.
In the graphical visualization, the total displacement with rigid body motion removed, can be seen. Since the soda can deforms so much and buckles within itself, the surface is partially no longer visible to the camera/s and as such, there are areas that cannot be correlated. The soda can actually twists when compressed, creating an central angled fold line and two horizontal fold lines in the can. The fold lines measure ca. 7 mm. From the 3D-visualization, the benefit of the 3-camera setup can be seen in that the shape of the soda can is captured. From the temporal plot of the line gauge, it is clear that the soda can was crushed by ca. 45 mm.