FEM ConstraintSelfWeight: Difference between revisions

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Defines gravity acceleration 9,81 m/s^2 acting on the whole model in the prescribed direction.
Defines a gravity acceleration of 9,81 m/s^2 acting on the whole model in the prescribed direction.


==Usage== <!--T:3-->
==Usage== <!--T:3-->

Revision as of 16:00, 27 September 2023

FEM ConstraintSelfWeight

Menu location
Model → Mechanical Constraints → Constraint self weight
Workbenches
FEM
Default shortcut
None
Introduced in version
-
See also
FEM tutorial

Description

Defines a gravity acceleration of 9,81 m/s^2 acting on the whole model in the prescribed direction.

Usage

  1. There are several ways to invoke the command:
    • Press the FEM ConstraintSelfWeight button.
    • Select the Model → Mechanical Constraints → Constraint self weight option from the menu.
  2. You can modify the direction of gravitation by changing its vector coordinates in the property bar of newly created ConstraintSelfWeight object.

Scripting

New object:

import ObjectsFem
ObjectsFem.makeConstraintSelfWeight(name)

Add object to the analysis named Analysis:

App.ActiveDocument.Analysis.Member = App.ActiveDocument.Analysis.Member + [(object)]

Example:

import ObjectsFem
selfweight_obj = ObjectsFem.makeConstraintSelfWeight("MySelfWeightObject")
App.ActiveDocument.Analysis.Member = App.ActiveDocument.Analysis.Member + [selfweight_obj]

Solver CalculiX

Limitations

  • You need to modify the .inp file to edit gravity acceleration.
  • Self-weight is applied to the element set Eall which includes the whole model.

Editing CalculiX input file

The acceleration constant can be manually edited after generating the CalculiX input file.

Example of lines in the .inp file:

*DLOAD
Eall,GRAV,9810,0.0,0.0,-1.0

where 9810 is a gravity acceleration magnitude in [mm/s^2], and 0,0,-1 is the direction vector.

Solver Z88

  • not implemented in Z88 solver (March 2017)