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femodel

Finite element analysis model object

Since R2023a

Description

An femodel object contains information about a finite element problem: analysis type, geometry, material properties, boundary conditions, loads, initial conditions, and other parameters.

Creation

Description

example

model = femodel(AnalysisType=analysistype) creates a finite element analysis model for the specified analysis type.

example

model = femodel(AnalysisType=geometry,Geometry=Geometry) also assigns the specified geometry object to its Geometry property.

Input Arguments

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Type of problem, specified as one of these values:

  • "structuralStatic" creates a model for static structural analysis.

  • "structuralModal" creates a model for modal structural analysis.

  • "structuralTransient" creates a model for transient structural analysis.

  • "structuralFrequency" creates a model for frequency response structural analysis.

  • "thermalSteady" creates a model for steady-state thermal analysis.

  • "thermalModal" creates a model for modal thermal analysis.

  • "thermalTransient" creates a model for transient thermal analysis.

  • "electrostatic" creates a model for electrostatic analysis.

  • "magnetostatic" creates a model for magnetostatic analysis.

  • "electricHarmonic" creates a model for harmonic electromagnetic analysis with an electric field type.

  • "magneticHarmonic" creates a model for harmonic electromagnetic analysis with a magnetic field type.

  • "dcConduction" creates a model for DC conduction analysis.

This argument sets the AnalysisType property.

Data Types: char | string

Geometry description, specified as an fegeometry object. This argument sets the Geometry property.

Properties

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Type of problem, specified as "structuralStatic", "structuralModal", "structuralTransient", "structuralFrequency", "thermalSteady", "thermalModal", "thermalTransient", "electrostatic", "magnetostatic", "electricHarmonic", "magneticHarmonic", or "dcConduction".

This property is set by the analysistype input argument.

Data Types: string

Geometry description, specified as an fegeometry object. This property is set by the geometry input argument.

Type of two-dimensional problem, specified as "planeStress", "planeStrain", or "axisymmetric". This property does not apply to models with 3-D geometries.

Data Types: string

Material properties, specified as a 1-by-N array of materialProperties objects. Here, N is the number of faces in a 2-D geometry or number of cells in a 3-D geometry. Each materialProperties object contains material properties for one face or cell of the geometry.

Boundary Conditions

Boundary conditions on geometry faces, specified as a 1-by-N array of faceBC objects. Here, N is the number of faces in a geometry. Each faceBC object contains boundary conditions for one face of the geometry.

Boundary conditions on geometry edges, specified as a 1-by-N array of edgeBC objects. Here, N is the number of edges in a geometry. Each edgeBC object contains boundary conditions for one edge of the geometry.

Boundary conditions on geometry vertices, specified as a 1-by-N array of vertexBC objects. Here, N is the number of vertices in a geometry. Each vertexBC object contains boundary conditions for one vertex of the geometry.

Settings for modeling thermal radiation between surfaces without conductive media, specified as a surfaceToSurfaceSettings object. The default empty value results in the surface-to-ambient solution.

Loads

Loads on geometry cells, specified as a 1-by-N array of cellLoad objects. Here, N is the number of cells in a geometry. Each cellLoad object contains loads for one cell of the geometry.

Loads on geometry faces, specified as a 1-by-N array of faceLoad objects. Here, N is the number of faces in a geometry. Each faceLoad object contains loads for one face of the geometry.

Loads on geometry edges, specified as a 1-by-N array of edgeLoad objects. Here, N is the number of edges in a geometry. Each edgeLoad object contains loads for one edge of the geometry.

Loads on geometry vertices, specified as a 1-by-N array of vertexLoad objects. Here, N is the number of vertices in a geometry. Each vertexLoad object contains loads for one vertex of the geometry.

Initial Conditions

Initial conditions on geometry cells, specified as a 1-by-N array of cellIC objects. Here, N is the number of cells in a geometry. Each cellIC object contains initial conditions for one cell of the geometry.

Initial conditions on geometry faces, specified as a 1-by-N array of faceIC objects. Here, N is the number of faces in a geometry. Each faceIC object contains initial conditions for one face of the geometry.

Initial conditions on geometry edges, specified as a 1-by-N array of edgeIC objects. Here, N is the number of edges in a geometry. Each edgeIC object contains initial conditions for one edge of the geometry.

Initial conditions on geometry vertices, specified as a 1-by-N array of vertexIC objects. Here, N is the number of vertices in a geometry. Each vertexIC object contains initial conditions for one vertex of the geometry.

Other Parameters

Mass proportional damping, specified as a nonnegative number.

Data Types: double

Stiffness proportional damping, specified as a nonnegative number.

Data Types: double

Reference temperature for a thermal load, specified as a real number. The reference temperature corresponds to the state of zero thermal stress of the model. The value 0 implies that the thermal load is specified in terms of the temperature change and its derivatives.

To specify the reference temperature for a thermal load in your model, assign the property value directly, for example, model.ReferenceTemperature = 10. To specify the thermal load itself, use cellLoad.

Data Types: double

Algorithm options for the PDE solvers, specified as a PDESolverOptions object. The properties of PDESolverOptions include absolute and relative tolerances for internal ODE solvers, maximum solver iterations, and so on. For a complete list of properties, see PDESolverOptions Properties.

Constants

Permittivity of vacuum for the entire model, specified as a positive number. This value must be consistent with the units of the model. If the model parameters are in the SI system of units, then the permittivity of vacuum must be 8.8541878128e-12.

Data Types: double

Permeability of vacuum for the entire model, specified as a positive number. This value must be consistent with the units of the model. If the model parameters are in the SI system of units, then the permeability of vacuum must be 1.2566370614e-6.

Constant of proportionality in Stefan-Boltzmann law governing radiation heat transfer, specified as a positive number. This value must be consistent with the units of the model. Values of the Stefan-Boltzmann constant in commonly used systems of units are:

  • SI —5.670367e-8 W/(m2·K4)

  • CGS— 5.6704e-5 erg/(cm2·s·K4)

  • US customary — 1.714e-9 BTU/(hr·ft2·R4)

Data Types: double

Object Functions

generateMeshCreate triangular or tetrahedral mesh
pdegplotPlot PDE geometry
pdemeshPlot PDE mesh
solveSolve structural analysis, heat transfer, or electromagnetic analysis problem

Examples

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Create a model for solving a thermal transient problem.

model = femodel(AnalysisType="thermalTransient")
model = 
  1x1 femodel array

Properties for analysis type: thermalTransient

            AnalysisType: "thermalTransient"
                Geometry: [0x0 fegeometry]
              PlanarType: ""
      MaterialProperties: [0x0 materialProperties]

   Boundary Conditions
                  FaceBC: [0x0 faceBC]
                  EdgeBC: [0x0 edgeBC]
                VertexBC: [0x0 vertexBC]
        ThermalRadiation: []

   Loads
                CellLoad: [0x0 cellLoad]
                FaceLoad: [0x0 faceLoad]
                EdgeLoad: [0x0 edgeLoad]
              VertexLoad: [0x0 vertexLoad]

   Initial Conditions
                  CellIC: [0x0 cellIC]
                  FaceIC: [0x0 faceIC]
                  EdgeIC: [0x0 edgeIC]
                VertexIC: [0x0 vertexIC]

   Other Parameters
            DampingAlpha: 0
             DampingBeta: 0
    ReferenceTemperature: []
           SolverOptions: [1x1 pde.PDESolverOptions]

   Constants
         StefanBoltzmann: []

  Show all properties

Create a model for solving a static plane-strain structural problem.

Create an femodel object for solving a static structural problem, and assign a 2-D geometry to the model.

model = femodel(AnalysisType="structuralStatic", ...
                Geometry="PlateHolePlanar.stl")
model = 
  1x1 femodel array

Properties for analysis type: structuralStatic

            AnalysisType: "structuralStatic"
                Geometry: [1x1 fegeometry]
              PlanarType: "planeStress"
      MaterialProperties: [0x1 materialProperties]

   Boundary Conditions
                  FaceBC: [0x1 faceBC]
                  EdgeBC: [0x5 edgeBC]
                VertexBC: [0x5 vertexBC]

   Loads
                FaceLoad: [0x1 faceLoad]
                EdgeLoad: [0x5 edgeLoad]
              VertexLoad: [0x5 vertexLoad]

   Other Parameters
    ReferenceTemperature: []
           SolverOptions: [1x1 pde.PDESolverOptions]

  Show all properties

By default, femodel assumes that a 2-D problem is a plane-stress problem. Specify the plane-strain problem type.

model.PlanarType = "planeStrain";
model.PlanarType
ans = 
"planeStrain"

Create a geometry of a beam.

gm = multicuboid(0.5,0.1,0.1);

Plot the geometry.

pdegplot(gm,FaceAlpha=0.5, ...
            FaceLabels="on", ...
            EdgeLabels="on")

Figure contains an axes object. The axes object contains 6 objects of type quiver, text, patch, line.

Create an femodel object for solving a static structural problem, and assign the geometry to the model.

model = femodel(AnalysisType="structuralStatic", ...
                Geometry=gm)
model = 
  1x1 femodel array

Properties for analysis type: structuralStatic

            AnalysisType: "structuralStatic"
                Geometry: [1x1 fegeometry]
      MaterialProperties: [0x1 materialProperties]

   Boundary Conditions
                  FaceBC: [0x6 faceBC]
                  EdgeBC: [0x12 edgeBC]
                VertexBC: [0x8 vertexBC]

   Loads
                CellLoad: [0x1 cellLoad]
                FaceLoad: [0x6 faceLoad]
                EdgeLoad: [0x12 edgeLoad]
              VertexLoad: [0x8 vertexLoad]

   Other Parameters
    ReferenceTemperature: []
           SolverOptions: [1x1 pde.PDESolverOptions]

  Show all properties

Specify Young's modulus, Poisson's ratio, and the mass density.

model.MaterialProperties = materialProperties(YoungsModulus=210e3, ...
                                              PoissonsRatio=0.3, ...
                                              MassDensity=2.7e-6);
model.MaterialProperties
ans = 
  1x1 materialProperties array

Properties for analysis type: structuralStatic

Index    CTE    PoissonsRatio    YoungsModulus    MassDensity    ShearModulus
  1      []        0.3000           210000        2.7000e-06          []     

  Show all properties

Specify a gravity load on the beam.

model.CellLoad = cellLoad(Gravity=[0;0;-9.8]);
model.CellLoad
ans = 
  1x1 cellLoad array

Properties for analysis type: structuralStatic

Index       Gravity       AngularVelocity    Temperature
  1      [0 0 -9.8000]          []               []     

  Show all properties

Specify that face 5 is a fixed boundary.

model.FaceBC(5) = faceBC(Constraint="fixed");
model.FaceBC
ans = 
  1x6 faceBC array

Properties for analysis type: structuralStatic

Index    Constraint    XDisplacement    YDisplacement    ZDisplacement
  1          []             []               []               []      
  2          []             []               []               []      
  3          []             []               []               []      
  4          []             []               []               []      
  5        fixed            []               []               []      
  6          []             []               []               []      

  Show all properties

Generate a mesh and assign the result to the model. This assignment updates the mesh stored in the Geometry property of the model.

model = generateMesh(model);

Solve the model.

R = solve(model)
R = 
  StaticStructuralResults with properties:

      Displacement: [1x1 FEStruct]
            Strain: [1x1 FEStruct]
            Stress: [1x1 FEStruct]
    VonMisesStress: [7888x1 double]
              Mesh: [1x1 FEMesh]

Plot the von Mises stress.

pdeviz(R.Mesh,R.VonMisesStress)

Figure contains an object of type pde.graphics.pdevisualization.

ans = 
  PDEVisualization with properties:

        MeshData: [1x1 FEMesh]
       NodalData: [7888x1 double]
     MeshVisible: off
    Transparency: 1
        Position: [0.1300 0.1100 0.6733 0.8150]
           Units: 'normalized'

  Use GET to show all properties

Version History

Introduced in R2023a

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