Equivalent Pseudo Rigid Body Mechanisms

pinshape

These three prongs are compliant mechanisms -  things that change a mechanical input into a mechanical output by flexing  (bending).  They are also pseudo rigid body mechanisms, meaning that their motion is designed by approximating rigid body mechanics. They are designed to be equivalent because they are supposed to have roughly the same spring constant and deflect the same amount per the force applied to bend them. If you close your eyes and push down on the end of the beam it should feel the same. This was printed in PLA with 2 shells, 10% infill and the print materials and settings affect how stiff the mechanism is. These three pseudo rigid body mechanisms are different beams that approximate a pin joint  (or revolute joint) with a torsional spring. From left to right they are  a short cantilever beam, a fixed-pinned cantilever beam and an initially curved fixed-pinned cantilever beam.  These different pseudo rigid body models are all derived from an elliptic-integral solid mechanics model of the path of a bending beam, with different assumptions to solve the problem. If you want to know more about it look at the slides from my Compliant Mechanisms Independent Project 's final presentation here https://docs.google.com/presen... .   For more of my 3D printing posts, check out my Google plus collection where you can click the notification bell to receive further alerts about new posts. https://plus.google.com/u/0/co...