Today was a very productive day. While Ted worked on the strain gauges (they each have to be glued onto the side of the sample and then soldered to wires), I calibrated the LVDT. The box on the left provides an excitation voltage to the LVDT, which is a cylinder with a hollow in the middle. Using that little Schaevitz tool in the foreground, I systematically inserted a core piece into the hollow of the LVDT a half millimeter at a time. With each increment, the LVDT puts out a different voltage, which is measured by the box on the right. I make a plot of distance versus voltage that tells us the calibration factor for our experiments.
Meanwhile, Heather checked the gauges and put a protective coating on the load cells. We use homemade load cells here, which is unusual I think. We will put one on the side of the sample to measure the horizontal load and one on the top to measure the vertical.