Simulation Settings

The Simulation Settings dialog is used to edit the solver parameters.

This dialog contains the following tabs:

Static Tab

Below are descriptions of the options in the Static tab of the Simulation Settings dialog.
Option Description
Method Select the type of Static solver method from the drop down:
  Force Imbalance - Type S Uses the Force Imbalance Method to calculate static equilibrium.
  Force Imbalance - Type D Force Imbalance Method that uses a time integration approach for quasi-static simulation. Not applicable for Static simulation (MotionSolve defaults to Force Imbalance – Type S) for pure static simulation. While using this method, the solver also uses the Transient simulation settings.
  MKEAM Uses the Maximum Kinetic Energy Attrition Method based on conservation of energy. This method is suitable for models with contacts. This method does not work for quasi-static simulation.
  The following options are available if Force Imbalance - Type D/Type S is chosen:
  Maximum residual This specifies the upper limit for the change in residual of the system equations at the static equilibrium point.
  Maximum imbalance Specifies the maximum force imbalance in the equations of motion that is allowed at the solution point.
  Maximum number of iterations Specifies the maximum number of iterations that are allowed before simulation stops.
  Stability Specifies the fraction of the mass matrix that is to be added to the Jacobian to ensure that it is not singular.
  The following options are available if MKEAM is chosen:
  Maximum number of iterations Specifies the maximum number of iterations that are allowed before simulation stops.
  Maximum residual kinetic energy tolerance Specifies the maximum allowable residual kinetic energy of the system at the static equilibrium point.
  Maximum coordinate difference tolerance This specifies the upper limit for the change in system states at the static equilibrium point.

Transient Tab

Below are descriptions of the options in the Transient tab of the Simulation Settings dialog.
Option Description
Integrator type Select the type integrator from the drop down:
  • ABAM
  • VSTIFF
  • MSTIFF
  • DSTIFF
  The following common options are available for all integrators:
  Integrator tolerance Represents the maximum absolute error per step that the integrator is allowed in computing the displacement, velocity, and differential equations states.
  Maximum step size Defines the maximum step size the integrator is allowed to take.
  Maximum initial step size The maximum initial step size.
  Minimum step size Defines the minimum step size the integrator is allowed to take.
  Maximum order Specifies the maximum order that the integrator is to take.
  Velocity tolerance fact The factor that multiplies integr_tol to yield the error tolerance for velocity states. For the DSTIFF integrator, this option is only applicable when the DAE index is set to 1 and the Velocity control option is selected.
  The following options are specific to DSTIFF:
  DAE index The index of the DAE formulation. Options available are: 3 or 1.
  DAE corrector max iteration The maximum number of iterations that the corrector is allowed to take to achieve convergence.
  DAE constraint tolerance The tolerance on all algebraic constraint equations that the corrector must satisfy at convergence.
  Initial no. of Jacobian matrix evaluation This attribute controls the Jacobian matrix evaluation during corrector iterations. Options available are: Auto|1|2|3.
Auto
The solver automatically determines when a new Jacobian needs to be calculated.
Value n (1, 2, or 3)
Indicates the nth iteration at which a new Jacobian is calculated.
  Velocity control The logical flag that controls whether the velocity states are checked for local integration error at each step. This option is only available in the case where the DAE index = 1.
  The following options are specific to VSTIFF/MSTIFF/ABAM:
  Constraint tolerance Defines the accuracy to which the system configuration and motion constraints are to be satisfied at each step.

Linear Tab

Below are descriptions of the options in the Linear tab of the Simulation Settings dialog.
Option Description
Eigen values and vectors (.eig, .h3d) Specifies whether the eigenvalue and eigenvector data is written to a .eig file.
Disable damping Specifies whether the linearization solver should disable damping from all force elements for the eigenvalue solution.
Kinetic energy distribution Specifies whether the modal kinetic energy distribution is written out to the solver log file and the *_linz.mrf output file.
Generate State Space Matrix
Altair Compose/Activate OML
Specifies whether the A, B, C and D matrices are to be written out into a .oml file that can be read in by Compose/Activate.
MATLAB
Specifies whether the A, B, C and D matrices are to be written out into a file that can be read in by MATLAB.
Simulink
Specifies whether the A, B, C and D matrices are to be written out in Simulink MDL format or not.

General Tab

Below are descriptions of the options in the General tab of the Simulation Settings dialog.
Option Description
Number of CPU cores in multiprocessor (SMP) run Specifies the number of CPU cores to be used when multiple cores are available. This is particularly helpful in parallelizing computations in the case of Contact simulation.
Mesh coarseness of CADGraphics for contacts Default coarseness setting for meshing CADGraphics when in contact. MotionView will use this setting while generating a mesh during solver export for those CADGraphics on which mesh coarseness has not been individually set.
Active contact iteration With this option selected, the contact force will be considered for residual evaluation during corrector iteration of the solver. While this option is useful to improve the simulation’s robustness in case of high oscillations, it can lead to a decrease in performance for other cases.
Default location for solver run files The default location for solving. When not specified, the solver deck is written at the model location.