FEM CalculiX Cantilever 3D/ru

Введение
Этот пример предназначен для того, чтобы показать, как выглядит простой анализ методом конечных элементов (МКЭ/FEA) в верстаке FEM в интерфейсе FreeCAD, и как можно визуализировать результаты. Показывается, как запустить (МКЭ) и как изменить значение нагрузки и направление нагрузки. Более того, поскольку файл примера предоставляется при любой установке FreeCAD, это полезная и простая проверка, позволяющая убедиться в правильности настройки верстака FEM.



Требования

 * Совместимая версия FreeCAD, указанная в описании учебника.
 * Ипользуйте для просмотра версии установленного FreeCAD
 * 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.

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 [[Image:FEM_Analysis.png|32px]] 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 a static mechanical analysis.
 * [[Image:FEM_Analysis.png|32px]] analysis container
 * 1) [[Image:FEM_Solver.png|32px]] a solver
 * 2) [[Image:FEM_Material.png|32px]] a material
 * 3) [[Image:FEM_FixedConstraint.png|32px]] a fixed constraint
 * 4) [[Image:FEM_ForceConstraint.png|32px]] a force constraint
 * 5) [[Image:FEM_Create.png|32px]] a FEM mesh
 * Since in the example here the results are included as well there is a sixth object, the results [[Image:FEM ShowResult.png|16px]].

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 [[Image:FEM ShowResult.png|16px]] 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 [[Image:FEM_PurgeResults.png|32px]] Purge results

Running the FEA

 * In Tree view double click on the solver object [[Image:FEM_Solver.png|32px]].
 * In task panel 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 . 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 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 [[Image:FEM_Solver.png|32px]] of the analysis [[Image:FEM_Analysis.png|32px]].
 * In the icon toolbar click on  [[Image:FEM_RunCalculiXccx.png|32px]] 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 [[Image:FEM_Create.png|32px]] and press the key.
 * Result: 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 panel
 * In the task window change the load value to 500000000 N = 500 MN (Note: force unit in task window has to be in N)
 * Click on the button.
 * On the geometrical model click on one of the long edges in x-direction.
 * Result: The red arrowsnthat illustrate force will change their direction in x-direction. They indicate 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 in task window.
 * Turn the visibility of the FEM mesh [[Image:FEM_Create.png|32px]] on by selecting it in tree view and pressing the 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 верстака FEM.
 * Теперь вы готовы проделать второй учебник FEM.
 * Мы создадим консоль CalculiX самостоятельно и сравним результаты с теорией балки.