FEM Анализ деформации консольной балки 3D (CalculiX)

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Руководство
Тема
Finite Element Analysis
Уровень
Beginner
Время для завершения
10 minutes
Авторы
Bernd
FreeCAD версия
0.16.6377 or above
Примеры файлов
Смотрите также
None

Введение

Этот пример предназначен для того, чтобы показать, как выглядит простой анализ методом конечных элементов (МКЭ/FEA) во FreeCAD FEM Module и как можно визуализировать результаты. Показано, как запустить (МКЭ) и как изменить значение нагрузки и направление нагрузки. Более того, поскольку файл примера предоставляется при любой установке FreeCAD, легко проверить, правильно ли установлен модуль FEM.

Требования

  • FreeCAD версия = 0.16.6377 или выше.
  • Это можно проверить в меню Справка -> о FreeCAD. Номер редакции должен быть больше 6377
  • Не требуется никакого внешнего программного обеспечения для загрузки файла примера, просмотра сетки и геометрии, а также для визуализации результатов.
  • Для повторного запуска FEA на вашем компьютере должно быть установлено программное обеспечение CalculiX. Возможно, решатель уже установлен вместе с FreeCAD. Если решатель CalculiX не установлен, см. FEM Install.

Set up the example file

Load Start Workbench

  • Start FreeCAD
  • The Start Workbench should be loaded

Load the example file

  • Go to the example projects and click on "Load an FEM analysis example"
  • If due to further operations some geometry, constraints or the results are broken or deleted just repeat the steps above.


Activate the analysis container

  • To work with an analysis the analysis has to be activated.
  • In tree view right click on the MechanicalAnalysis → Activate analysis


Analysis container and its objects

  • If the analysis is activated FreeCAD itself will change the current workbench to FEM.
  • There are at least the 5 objects needed to make an static mechanical analysis.
  • analysis container
  1. a solver
  2. a material
  3. a fixed constraint
  4. a force constraint
  5. File:FEM Create.png a FEM mesh
  • Since in the example here the results are included as well there is a sixth object, the results .


Visualizing Results

  • Be sure the analysis is activated.
  • Be sure the analysis still contains the result object, if not just reload the example file.
  • Click in icon toolbar on Show result
  • In task window choose z-Displacement. It shows -88.443 mm in negative z-direction.
  • This makes sense since the force is in negative z-direction as well.
  • Activate the check box besides the bottom slider of displacement show.
  • The slider can be used to alter the mesh to view the deformation in a simplified manner.
  • Choose among the different Result types to view all in the GUI available result types.


Purging Results

  • Be sure the analysis is activated.
  • To remove the results select in the icon toolbar Purge results

Running the FEA

  • In Tree view double click on the solver object .
  • In task window of the solver object make sure static analysis is selected.
  • Click on write .inp file in the same task window. Watch the log window until it prints "write completed."
  • Click on Run CalculiX. Since this is a very small analysis it should take less than a second to run.
  • In the text window it should print in green letters "CalculiX done!" and in the next line "loading result sets ..."
  • You just have finished your first FEA in FreeCAD if there has not been any error message.
  • Click on Close in the task window.
  • A new result object should be created. You know how to visualize the results already.
  • If you get an error message no solver binary or similar when triggering the analysis check FEM Install.

Running the FEA the fast Way

  • In tree view select the solver object of the analysis .
  • In the icon toolbar click on Quick Analysis.
  • The Calculix input file will be written, CalculiX will be triggered and the result object should be created.

Changing Load Direction and Load Value

  • In tree view select the FEM mesh object File:FEM Create.png and press the space key.
  • The visibility of the FEM mesh will be turned off. The geometrical model is still visible.
  • In tree view double click on the force constraint object to open its task window.
  • In the task window change the load value to 500000000 N = 500 MN (force unit in task window has to be in N)
  • Click on Button Direction.
  • On the geometrical model click on on of the long edges in x-direction.
  • The red arrows of the force will change their direction in x-direction. They show to the fixed direction.
  • Since tension should be applied to the box the Reverse Direction needs to be triggered by clicking on it.
  • The red arrows of the force will change their direction.
  • Click on OK in task window.

  • Turn the visibility of the FEM mesh File:FEM Create.png on by selecting it in tree view and pressing the space key.
  • You know how to trigger an analysis and how to visualize results already.
  • The deformation in x-direction should be 19.05 mm.

Что дальше?

  • Теперь мы закончили с основным рабочим процессом для FEM Module.
  • Теперь вы готовы сделать второй FEM tutorial.
  • Мы создадим консоль CalculiX самостоятельно и сравним результаты с теорией пучка.