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Unread 11-04-2014, 11:36
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Re: Out stretching surgical tubing.

Quote:
Originally Posted by menns View Post
The curious thing we discovered about stretching surgical tubing is that the restoring force decrease by about 10% for about 40 seconds to a minute after it's stretched. We get the most catapulting force if we stretch it and release it immediately. We suspect this was throwing off our two ball autonomous.

I'm guessing this a thermal effect. Rubber produces heat when stretched. It then cools to room temperature but rubber expands when it cools so less restoring force.
Something doesn't quite add up here, are you sure it was the surgical tubing causing variation? If there is a power loss from the tubing, it should be a steady decline and not self restored. Maybe over time the tubing slides or rotates where it is mounted and changes its tension, just a thought.