RIGIDBODY_TimeIntegrationVersion

If a geometric body is a RIGIDBODY or a MassSpringDashpot, then the time integration of the equations of motion is solved explicitly. If also body-body and body-boundary collisions should be detected (see RIGIDBODY_UseCollisionModel), the time integration of the rotation has to be reduced from quasi-analytical to first/second order in time. Default: RIGIDBODY_TimeIntegrationVersion = 2

RIGIDBODY_TimeIntegrationVersion	Description
1	Second order for the velocity but quasi-analytical for the rotation (exact integration of the Euler equation for rotation).
2 (default)	Second order for the velocity and rotation. In this way, implicit collision and joint/link forces can be taken into account.

Note: In order to detect collisions correctly, make sure to use RIGIDBODY_TimeIntegrationVersion = 2.

Advanced Options for Collision Detection

Default: RIGIDBODY_TimeIntegrationVersion = [ 2.0, 0.0, 0.0, 0.0, 0.5, 1e5 ]

Value	Description
N_sub	Permissible number of sub-iterations for the RIGIDBODY structure per time cycle, so the numerical time step size for the RIGIDBODY structure (RB) would be \( \Delta t_\text{sub}=\frac{\Delta t_\text{MESHFREE}}{N_\text{sub}}\)
dt_fix	Numerical time step size for the RIGIDBODY structure
extrapolationRigidBodyForces	extrapolate the forces/moments acting on the COG a little bit into the future by \( \mathbf{F}_{applied}^{n} = (1+\alpha) \cdot \mathbf{F}^n - \alpha \cdot \mathbf{F}^{n-1},\) where the dynamics of the RIGIDBODY is updated by \( \mathbf{v}^{n+1} = \mathbf{v}^n + \frac{\nabla t}{m} \mathbf{F}_{applied}^{n}.\) Similarly, we treat an applied moment for the rotation of the body.
	Remark: Choosing \( \alpha=0.5\) would result in a second order ansatz for the forces/moments. This might be very precise, but maybe unstable.
extrapolationSpringSashpotForces	Similar to the above parameter, the forces for a MassSpringDashpot are extrapolated.
MaxNiterAbort	Maximum upper limit for the number of sub-iterations above which the simulation will be aborted. Typically, during collisions or computation of contact forces the RIGIDBODY sub-timestep falls below the user-prescribed dt_fix. This may create extremely small time steps and result in a non-converging solution. With this value you can provide an upper limit to abort the simulation.
	Default: 1e5, i.e. for each time step the maximum number of sub-iterations equals 1e5.
	Remark: By putting a minus sign in front of this value, the abort of the running simulation is suppressed and instead the simulation continues.

Taking into account the optional arguments, the numerical time step size for the RIGIDBODY structure is \( \Delta t_\text{RB} = \min \left( \Delta t_\text{sub} , \Delta t_\text{fix} \right).\)