Pre-Stress

Defines an upstream structural analysis whose stress results are to be used in a Prestressed Coupled Field Harmonic Analysis, Prestressed Coupled Field Modal Analysis, Harmonic Acoustics Analysis, Harmonic Response Analysis, Modal Analysis, or Modal Acoustics Analysis, whose stress-stiffening effects are to be used in a Eigenvalue Buckling Analysis, or whose stresses, strains, and/or displacements, or velocities are to be used in an Explicit Dynamics Analysis.

Pre-Stress Object for Harmonic Response

Object Properties

Tree Dependencies

Insertion Methods

API Reference

Additional Related Information

Pre-Stress Object for Modal

 
Pre-Stress Object for Eigenvalue Buckling

 
Pre-Stress Object for Explicit Dynamics

 

Object Properties

The Details Pane for this object includes the following properties.

CategoryProperties/Options/Descriptions
Definition

Pre-Stress Environment: Using this property, you specify the upstream structural analysis you wish to link to the current analysis. The application uses the stress results from the specified structural analysis in the current analysis.

Eigenvalue Buckling, Harmonic Response, Modal, or Substructure Generation Environments Only:
Pre-Stress Define By: Specify this property as Program Controlled (default), Load Step, or Time.
Pre-Stress Loadstep: Displays when Pre-Stress Define By is specified as Load Step. Enter the load step of Static Structural analysis that you’ll use as the starting point to begin your Harmonic Response, Modal, or Eigenvalue Buckling analysis. The default value is Last.
Pre-Stress Time: Displays when Pre-Stress Define By is specified as Time. Enter the time from the Static Structural analysis that you want to use as the starting point to begin your Harmonic Response, Modal, or Eigenvalue Buckling analysis. The default value is End Time.
Reported Loadstep: Read-only field.
Reported Substep: Read-only field.
Reported Time: Read-only field.
Contact Status: Options include Use True Status, Force Sticking, Force Bonded.
Newton-Raphson Option: Read-only field for Pre-Stressed Modal Analyses. Indicates whether the property was selected in the prestressed environment. Options include Program Controlled, Full, Modified, and Unsymmetric.
Coupled Field Modal, Coupled Field Harmonic, and Substructure Generation Analyses Only

For the above analysis types, the application displays the Load Control property. You use this property to define load generation for prestressed analyses. Property options include:

  • Keep All: Keep all the boundary conditions (loads and constraints) from the end of the load step of the current restart point.

  • Keep Inertia and Displacement Constraints (default for Substructure Generation): Keeps Inertial loads and Displacement constraints All other loads and constraints are deleted.

  • Keep Displacement Constraints: All displacement constraints are kept, which includes zero and non-zero displacements.

  • Keep All Displacements as Zero (default for Coupled Field analyses): All displacement constraints are kept and all non-zero constrains are set to zero.

  • Delete All: Deletes all loads and constraints.

Note:  This property controls the LoadControl field of the Mechanical APDL PERTURB command.

Explicit Dynamics Environment Only:
Mode: Specify this property as Displacement or Material State.
Time Step Factor: Displays when Mode is specified as Displacement.
Pressure Initialization: Displays when Mode is specified as Material State. Specify this property as From Deformed State (default) or From Stress Trace.
Time: The time at which results are extracted from the implicit analysis.

Tree Dependencies

The Pre-Stress object has the following Outline structure.

  • Valid Parent Tree Objects: Coupled Field Harmonic, Coupled Field Modal, Harmonic Acoustics, Harmonic Response, Modal, Modal Acoustics, Eigenvalue Buckling, Explicit Dynamics, or Substructure Generation environment object.

  • Valid Child Tree Objects: Comment, Figure, and Image.

Insertion Methods

The object appears automatically for Coupled Field Harmonic, Coupled Field Modal, Harmonic Acoustics, Modal Acoustics, Harmonic Response, Modal, Eigenvalue Buckling, Explicit Dynamics, and Substructure Generation analyses.

API Reference

See the Initial Condition section of the ACT API Reference Guide for specific scripting information.

Additional Related Information

See the following sections for additional information: