Simulation Properties reference

The Simulation Properties dialog box displays values from the unique Stress Analysis Settings and representation information from the assembly. Then you specify the properties.

Access

On the Stress Analysis tab Manage panel, click Create Simulation .

In the browser, right-click a simulation node, and click Edit Simulation Properties.

Name

A user assigned name that defaults to Simulation, followed by a colon and a numeric indicator indexed from 1 to ‘n’. All user-visible references to the simulation use this name.

Design Objective

• Single Point Evaluates one set of geometry. New simulations default to this type.

• Parametric Dimension Optimizes or changes feature geometry using design parameters.

Reset

Replaces the current settings with the Stress Analysis Settings.

The new settings sometimes differ from the values that you set when you create the simulation.

Does not affect the Design Objective, Simulation Type, or Contact Settings.

Simulation Type tab

Static Analysis

Evaluates the model without motion to determine stresses and displacement.

Detect and Eliminate Rigid Body Modes

Removes the rigid body modes in problems where not enough constraints are defined, but they have a balanced load with a valid elasticity solution.

Separate Stress Across Contact Surfaces

Specifies explicit representation of discontinuous stress across the contact interface in the FEA formulation. Some components of the stresses can be discontinuous due to different materials of the contacting parts.

Motion Load Analysis

Transfers motion loads of a single part from Dynamic Simulation. Enables Part and Time Step controls.

• Part Lists available parts with motion loads that are exported.
• Time Step Lists available time steps associated with the part selection.

All other bodies are excluded and the associated Dynamic Simulation loads are imported.

Modal Analysis

Determine the natural frequencies of vibration for the model.

Number of Modes

Specifies the number of resonant frequencies to find for Structural Frequency. Includes frequencies corresponding to rigid body movements. For example, in a free vibration analysis the first six modes occur at 0Hz, corresponding to the six rigid body movements.

Frequency Range

Specifies the range of frequency for the desired modal frequencies. We recommend that you indicate both the range and the number of modes within the range. If the number of modes is unknown, Stress Analysis calculates up to 100 modes within the range.

Compute Preloaded Modes

Computes stress on a model, and then computes modes for the prestressed condition.

Enhanced Accuracy

Enhances the accuracy of the computed frequencies for the given problem, affecting only the first three modes. The solver employs an iterative scheme to compute the eigenvalues (frequencies) one at a time. The required accuracy in the eigenvalue computation is determined by checking the relative difference between the previous and current iterations. This translates to: relative_diff = abs(eigen_value_current - eigen_value_prev)/(eigen_value_current).

By default, if the relative difference is less than 1e-3, the iterations stop, and the required eigenvalue is considered achieved. When enhanced accuracy is enabled, convergence is checked for a relative difference of less than 1e-4, resulting in a relative error one order of magnitude smaller than the default.

Contacts

Tolerance

Specifies the maximum distance between faces or edges to consider in automatic detection. Faces or edges falling outside the distance are eliminated from participating in automatic contacts. You can enter the value in a different linear unit than the default document value.

Type

From the list of contact types, select the type to generate automatically when the simulation builds contacts. You can edit individual contacts and change the type later

Normal or Tangential Stiffness

Specifies the equivalent normal stiffness value. Applicable to Spring contact only. Note: Normal and tangential directionality is based on the best approximation between the two faces that follow each other in a parallel way. Examples are parallel planes, concentric cylinders, and so on. Otherwise it can be ambiguous.

Shell Connector Tolerance

Specifies the maximum ratio between shell gap and shell thickness used to bridge gaps within a mid surface. These gaps are connected using connectors. A connector is a system generated contact that helps to consider the mid surface as physically connected, even though it has gaps.

Model tab

Representations

Each assembly simulation maintains an association to each representation type. As you activate different simulations, the corresponding representation is activated for that simulation. You can change the representation association at any time. If you do so after you run a simulation, the results can be out of sync. If so, rerun the simulation.

Model State

Specifies the model state to use with the simulation. This selection can be a simplified model to reduce simulation and meshing time.

Design View

Specifies the design view representation to use with the simulation. Not available for Parts.

Positional

Specifies the positional representation to use with the simulation. Use positional representations to place components into a specific position or relationship with other components. Not available for Parts.

iAssembly/iPart Member

iAssemblies

Specifies the iAssembly member to be associated with the simulation. If the component is a factory member, the member selection is disabled. Available only when the assembly is an iAssembly factory.

iParts

If the part document is an iPart factory, you can associate a specific iPart member with the simulation.