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elastic energy

Posted: Tue Sep 12, 2017 12:17 pm
by ashmheers
Hello, all!
I am working on a model of a flapping bird wing, and I want to use CMC to figure out if two particular tendons are storing and releasing elastic energy. I've gotten CMC to work, and the muscle-tendon units in question certainly seem to be behaving like "anatogonistic" springs, in that they transition from negative to positive power in opposition to each other. But I want to know how much of the (positive) power is generating passively, by the tendons recoiling. I can get tendon and fiber lengths the plotting menu in OpenSim, and if I can get tendon and passive fiber forces I should be able to calculate what I need, I think. Do I need to use the Muscle Analysis tool to get those forces? The results from the Muscle Analysis looked a bit strange, but I haven't found any documentation explaining what all of the features in the muscle analysis tool are. Any suggestions on how to calculate elastic energy storage and release from CMC would be greatly appreciated! I'm actually located at Stanford — I'm a postdoc in Mechanical Engineering, in David Lentink's lab, so I can meet in person if that would be easier. Thanks in advance!

Re: elastic energy

Posted: Mon Sep 18, 2017 2:23 am
by tkuchida
if I can get tendon and passive fiber forces I should be able to calculate what I need, I think. Do I need to use the Muscle Analysis tool to get those forces?
The Muscle Analysis reports ~20 quantities, among which are tendon force and passive fiber force.