The rock and ice mechanics lab at Lamont-Doherty is led by PIs Heather Savage, Christine McCarthy and Ben Holtzman. We are in the process of growing our lab and building our experimental program. Along with a team of postdocs, undergrads, grads, and longtime staff engineer Ted, we are rehabilitating and revamping some of the old equipment and building new rigs for exciting new experiments on both rock and ice. You can follow along with our progress here.

Wednesday, 28 September 2011

a gaggle of strain gauges

Today we moved another big step closer to running an experiment by connecting strain gauges to the sample. Ted affixed various kinds of gauges along the business edge of the sample in order to measure strain that is parallel, perpendicular, and at 45 degrees to the frictional surface. The gauges are then soldered to a rainbow of wires that lead to that little green breakout box. Coming from the box are wired connectors that will plug into individual signal conditioners.
Each of 10 signal conditioners below are used to zero-out and amplify the response from the gauges and will then send a voltage output to the computer.
We were getting a little interference from the rainbow of wires and the output connections in the back were hard to reach, so Ted reconfigured it as below, with the strain wires now hiding safely inside the silver mesh tube. Although it looks a bit hectic this way, it works really well.
And "how on earth do we plug all those things into the computer?" you may ask. Well they first get connected to this BNC box. Then the BNC box is connected to a thing called a chassis (more on that later) that is, in turn, connected to a card in the back of the PC.

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