유한요소해석 작업환경

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소개

The FEM Workbench 는 프리캐드 속에서 유한요소해석 finite element analysis (FEA)을 현대적으로 진행하게 해줍니다. 해석을 완료 하는데 까지 필요한 모든 도구들을 모아 놓은 통합된 사용자 환경(GUI)이 있어서 현대적 이라는 겁니다.

진행 순서

유한요소 해석의 수행 순서 :

  1. 전 처리 : 해석 문제에 관한 설정.
    1. 모델의 형상 : 프리캐드로 형상을 생성 하거나, 다른 프로그램에서 만든 것을 도입 합니다.
    2. 해석 내용 생성.
      1. 모델 형상에 관한 지지점 조건과 재하 조건 등의 재현 할 내용을 추가 합니다.
      2. 모델 형상의 부분들이 어떤 물질인지 조건을 추가 함.
      3. 모델 형상에 관한 메쉬 요소를 생성 하거나, 다른 프로그램에서 만들어진 것을 도입 합니다.
  2. 해석 계산 : 프리캐드 상에서 외부의 해석기를 실행 시킵니다.
  3. 후 처리 : 해석 결과를 프리캐드 상에서 가시화 작업을 하거나, 다른 프로그램으로 '후 처리' 할 수 있도록 내보내기 합니다.

The FEM Workbench can be used on Linux, Windows, and Mac OSX. Since the workbench makes use of external solvers, the amount of manual setup will depend on the operating system that you are using. See FEM Install for instructions on setting up the external tools.

Workflow of the FEM Workbench; the workbench calls two external programs to perform meshing of a solid object, and perform the actual solution of the finite element problem

메뉴 : 모델

  • Analysis container: Creates a new container for a mechanical analysis. If a solid is selected in the tree view before clicking on it, the meshing dialog will be opened next.

물질

구성요소의 형태적 특성

  • 보의 단면: 보 요소에서 검토 할 단면을 지정하기 위해 사용 합니다.

전자기력 조건

유체에 관한 조건

Geometrical Constraints

Mechanical Constraints

  • Constraint tie: Used to define a tie constraint ("bonded contact") between two faces.
  • Constraint force: Used to define a force in [N] applied uniformly to a selectable face in a definable direction.

Thermal Constraints

Constraints without solver

Overwrite Constants

Menu: Mesh

  • FEM mesh region: Creates a localized area(s) to mesh which highly optimizes analysis time.
  • FEM mesh group: Groups and labels elements of a mesh (vertex, edge, surface) together, useful for exporting the mesh to external solvers.
  • Nodes set: Creates/defines a node set from FEM mesh.

Menu: Solve

  • Solver Z88: Creates the solver controller for Z88.

Menu: Results

  • Post pipeline from result: Used to add a new graphical representation of FEM analysis results (color scale and more display options).
  • Warp filter: Used to visualize the scaled deformed shape of the model.
  • Function cut filter: Used to display the results on a sphere or a plane cutting through the model.
  • Region clip filter: Used to clip a field with a sphere or a plane cutting through the model.
  • Filter functions: This is an icon menu in the FEM Results toolbar that holds the following commands:

Menu: Utilities

Context Menu

  • Clear FEM mesh: Deletes the mesh file from the FreeCAD file. Useful to make a FreeCAD file lighter.
  • Display FEM mesh info: Displays basic statistics of existing mesh - number of nodes and elements of each type.

Preferences

Information

The following pages explain different topics of the FEM Workbench.

FEM Install: a detailed description on how to set up the external programs used in the workbench.

FEM Mesh: further information on obtaining a mesh for finite element analysis.

FEM Solver: further information on the different solvers available in the workbench, and those that could be used in the future.

FEM CalculiX: further information on CalculiX, the default solver used in the workbench for structural analysis.

FEM Concrete: interesting information on the topic of simulating concrete structures.

Tutorials

Tutorial 1: FEM CalculiX Cantilever 3D; basic simply supported beam analysis.

Tutorial 2: FEM Tutorial; simple tension analysis of a structure.

Tutorial 3: FEM Tutorial Python; set up the cantilever example entirely through scripting in Python, including the mesh.

Tutorial 4: FEM Shear of a Composite Block; see the deformation of a block that is comprised of two materials.

Tutorial 5: Transient FEM analysis

Tutorial 6: Post-Processing of FEM Results with Paraview

Tutorial 7: FEM Example Capacitance Two Balls; Elmer's GUI tutorial 6 "Electrostatics Capacitance Two Balls" using FEM Examples.

Coupled thermal mechanical analysis tutorials by openSIM

Video tutorial 1: FEM video for beginner (including YouTube link)

Video tutorial 2: FEM video for beginner (including YouTube link)

Many video tutorials: anisim Open Source Engineering Software (in German)

Extending the FEM Workbench

The FEM Workbench is under constant development. An objective of the project is to find ways to easily interact with various FEM solvers, so that the end user can streamline the process of creating, meshing, simulating, and optimizing an engineering design problem, all within FreeCAD.

The following information is aimed at power users and developers who want to extend the FEM Workbench in different ways. Familiarity with C++ and Python is expected, and also some knowledge of the "document object" system used in FreeCAD is necessary; this information is available in the Power users hub and the Developer hub. Please notice that since FreeCAD is under active development, some articles may be too old, and thus obsolete. The most up to date information is discussed in the FreeCAD forums, in the Development section. For FEM discussions, advice or assistance in extending the workbench, the reader should refer to the FEM subforum.

The following articles explain how the workbench can be extended, for example, by adding new types of boundary conditions (constraints), or equations.

A developer's guide has been written to help power users in understanding the complex FreeCAD codebase and the interactions between the core elements and the individual workbenches. The book is hosted at github so multiple users can contribute to it and keep it updated.

Extending the FEM Workbench documentation