VIC-3D in High Wind Shingle Test at USC
Especially relevant in view of our recent brush with Hurricane Dorian, we were recently able to visit researchers in the College of Engineering and Computing at the University of South Carolina who continue an important project that involves testing the performance of asphalt shingles in extremely high wind conditions. Using a wind tunnel that can generate sustained wind of 150+mph (a category 5 hurricane), Dr. Michael Sutton, Dr. Sreehari Rajan, Troy Myers and others developed a digital image correlation (DIC) based testing technique to measure full-field displacements of roof shingles under high wind loads.
Deploying the powerful Correlated Solutions VIC-3D system, these researchers were able to visualize very small changes in deformation and strain as the wind took its toll on the shingles. Interestingly, the natural color variations on the shingle’s exposed surface provided a suitable speckle pattern for 3D-DIC measurements. The test showed that consistent 2D and 3D-DIC uplift displacement maps can be obtained up to failure. The evidence gained also highlights the importance of understanding the influence of time-dependent shingle material deformations, together with the progressive physical damage along the sealant strip used in modern roof design.
This work will be indispensable as new roofing solutions are developed in the face of increasingly severe climatic conditions. Check out this short video that explains more about this important research project and the exciting new digital image correlation system that makes it possible.
“Hi, my name is Sreehari Rajan, and I’m a graduate student at the University of South Carolina, and I’m working with Dr. Michael Sutton, and what we are doing here is a wind tunnel experiment on 3 tab shingles at 60mph, 90mph and finally 150mph wind speed to see how the shingles perform at these high wind loads. First, we’ll be doing a test at 60mph for 10 minutes and we’ll be recording the images of the shingles using a stereo visual system and we’ll be analyzing the images using Correlated Solutions VIC-3D software. After that, we will run the experiment at 90 mph and again at 150mph.
VIC-3D software will be used to analyze the speckle images and you can see that we have a natural speckle pattern on the shingles themselves because of the contrast you get from the minerals on the top of the shingles. VIC-3D helps us analyze by measuring the out of plane displacement and we can get a full-field deformation of the shingles which can be really useful in understanding the performance under high stress.”