...so does that make me dark and twisty?

The more I learn about the material properties of bone the more I want to learn about bones.  I love bones.  There are few things that are more perfect and amazing than bones and joints.  A really good beer ranks right up there, but bones still win. 

I thought they were pretty cool to start with, but after an evening of diving into project-related literature, I think I may have found my Mistress....or Mister, if that's what they call the dude that you're cheating on your husband with....if I had a husband.....

Neat fact for the day: a running person will put so much stress on their tibia (big bone in the lower leg) that it ranges between the yield strength (force required to start plastic deformation) and the ultimate strength (force to snap...because bone is more brittle than ductile), which is a really narrow range to start with.  Taking what they teach us about metals or brittle ceramics, in theory our bones should be breaking every time we land on a running stride.  Wicked hey!?  Also, figuring all this shit out is even more complicated because bone has the ability to regenerate itself.  Wonderful bone-building cells (osteoblasts) go in and fix little tiny stress fractures that we don't even notice and most of the time can't even detect.  AMAZING!!  How many metals can you think of that have the ability to regenerate themselves?  I didn't think so.  I'll come back when you can get me a real answer and not something that came up on Star Trek. 

We're taught to design stuff so that the stress is well below the yielding stress...the amount of force required to start yielding (or breaking if you want to look at it in pseudo-correct terms)...so well below that it can withstand 1.5 or 2 times the force before it snaps.  Obviously someone didn't read the safety manual when they went to design bones....or did they???  I dunno, I find this little tidbit puzzling, amazing and incredibly wicked, right up there with the so-close-to-perfect-and-frictionless-cartilage fact.  Sure makes me appreciate the wonder of the living body that much more. 

Right now, I'm loving my project.  Bones are the coolest thing! EVER!