Alessio Quaglino
7d8d4d398e
Before change: poncho 18.20s poncho_flex 44.60s floppy 4.70s floppy_flex 6.43s After change: poncho 18.23s poncho_flex 44.62s floppy 4.67s floppy_flex 6.57s PiperOrigin-RevId: 585952587 Change-Id: I0e7c1513f64c7ab1e6ad71e2168b4467c042b46f
Elasticity plugins
These are first-party plugins that implement passive forces based on discretized continuum mechanics models. They can be applied to flexes and bodies (via the composite functionality). Sample models can be found in this folder.
Cable
Implemented in cable.cc.
The cable plugin discretizes an inextensible 1D continuum. It is intended to simulate the twist and bending of rods where the stretching in negligible compared to the other deformation modes.
Parameters:
twist[Pa]: twisting stiffness.bend[Pa]: bending stiffness.flat[bool]: if true, the stress-equilibrium configuration is that of a straight cable; if true, it is the configuration defined in the XML.vmax[N/m^2]: If greater than zero, the cable is colored using mechanical stresses; the value represent the maximum stress in the color scale.
Shell
Implemented in shell.cc.
The shell plugin discretizes an inextensible 2D continuum. It is intended to simulate the bending of plates where the stretching is negligible compared to other deformation modes.
Parameters:
young[Pa]: Young's modulus.poisson[Pa]: Poisson's ratio; if 0, then the material only opposed shear deformations; if near 0.5, then the material is nearly incompressible (rubber-like).thickness[m]: shell thickness, used to scale the bending stiffness.
Membrane
Implemented in membrane.cc.
The membrane plugin discretized an extensible 2D continuum. It is intended to simulate the stretching of membranes subjected to tensile stresses, where the bending is negligible.
Parameters:
young[Pa]: Young's modulus.poisson[Pa]: Poisson's ratio; if 0, then the material only opposed shear deformations; if near 0.5, then the material is nearly incompressible (rubber-like).thickness[m]: shell thickness, used to scale the stretching stiffness.
Solid
Implemented in solid.cc.
The membrane plugin discretized an extensible 3D continuum. It is Saint Venant–Kirchhoff model intended to simulate the compression or elongation of hyperelastic materials subjected to large displacements (finite rotations) and small strains, since it uses a nonlinear strain-displacement but a linear stress-strain relationship.
Parameters:
young[Pa]: Young's modulus.poisson[Pa]: Poisson's ratio; if 0, then the material only opposed shear deformations; if near 0.5, then the material is nearly incompressible (rubber-like).damping[Ns/m^2]: damping coefficient for Rayleigh damping.