.. _gallery-fem: Finite Elements =============== Woo implements :ref:`plate (CST+DKT) ` and :ref:`tetrahedral (TET4) ` elements. They use corotated FEM formulation to decompose nodal displacements into rigid-body motion and element deformation. Mass and inertia is lumped into nodes. Horse ------ This first example shows :obj:`the horse ` constructed from membrane elements, then from volume elements (without bones): .. youtube:: 0H4r7ciuMBw .. youtube:: BG62QAXNxbQ Tube ---- The tube is triangulated and falls (including self-collisions) onto cylinders; the material is elastic and exhibits nicely geometrical non-linearities of the deformation: .. youtube:: cOLMNqtCy1c This is the same example, but rigid cylinders were replaced by deformable beam. This simulation can be found in :woosrc:`examples/tube.py`: .. image:: fig/tube-with-spheres.png :width: 100% Triaxial test with membrane ---------------------------- This simulation is made using the :obj:`woo.pre.cylTriax.CylTriaxTest` preprocessor bundled with Woo; details are described in :ref:`case-cyl-triax`. Triaxial test first compresses the sample isotropically, then applies hydrostatic pressurae laterally (here applied by the elastic membrane) while prescribing axial deformation. .. youtube:: Li13NrIyMYU Split membrane -------------- This membrane has a predefined split in the middle (used by some people to model broken plastic packaging); this example is to be found in :woosrc:`examples/membrane-split.py`. .. image:: fig/split.png :width: 100%