faceLoad

Load on geometry face

Since R2023a

Description

A faceLoad object contains a description of a load on a face of a geometry. An femodel object contains an array of faceLoad objects in its FaceLoad property.

Creation

Syntax

model.FaceLoad(FaceID) = faceLoad(Name=Value)

model.FaceLoad = faceLoad(Name=Value)

Description

model.FaceLoad(FaceID) = faceLoad(Name=Value) creates a faceLoad object and sets properties using one or more name-value arguments. This syntax assigns the specified structural, thermal, or electromagnetic load to the specified faces of the geometry stored in the femodel object model. For example, model.FaceLoad(1) = faceLoad(ChargeDensity=0.3) specifies the charge density on face 1.

model.FaceLoad = faceLoad(Name=Value) assigns the specified property to the entire geometry. For example, model.FaceLoad = faceLoad(Gravity=[0 -9.8]) specifies the gravity load on all faces of a 2-D geometry.

Input Arguments

FaceID — Face IDs

vector of positive integers

Face IDs, specified as a vector of positive integers. Find the face IDs using pdegplot with the FaceLabels value set to "on".

Data Types: double

Properties

Temperature — Thermal load

real number | SteadyStateThermalResults object | TransientThermalResults object

Thermal load, specified as a real number, SteadyStateThermalResults object, or TransientThermalResults object. This property must be specified in units consistent with those of the geometry and material properties. For TransientThermalResults, you can access results for a particular time-step by using the filterByIndex function.

Tip

If you specify a thermal load, you must also specify a reference temperature using model.ReferenceTemperature. For details, see the description of the ReferenceTemperature property in femodel.

Data Types: double

Heat — Heat source term

real number | function handle

Heat source term, specified as a real number or function handle. Use a function handle to specify an internal heat source that depends on space, time, or temperature. For details, see Nonconstant Parameters of Finite Element Model.

Pressure — Pressure normal to boundary

real number | function handle

Pressure normal to the boundary, specified as a real number or function handle. A positive-value pressure acts into the boundary (for example, compression), while a negative-value pressure acts away from the boundary (for example, suction).

If you specify Pressure as a function handle, the function must return a row vector where each column corresponds to the value of pressure at the boundary coordinates provided by the solver. For a transient structural model, Pressure also can be a function of time. For a frequency response structural model, Pressure can be a function of frequency (when specified as a function handle) or a constant pressure with the same magnitude for a broad frequency spectrum. For details, see Nonconstant Parameters of Finite Element Model.

Data Types: double | function_handle

ConvectionCoefficient — Convection to ambient boundary condition,

real number | function handle

Convection to ambient boundary condition, specified as a real number or function handle. Use a function handle to specify a convection coefficient that depends on space and time. For details, see Nonconstant Parameters of Finite Element Model.

Specify ambient temperature using the AmbientTemperature property. The value of ConvectionCoefficient is positive for heat convection into the ambient environment.

Data Types: double | function_handle

AmbientTemperature — Ambient temperature

real number

Ambient temperature, specified as a real number. The ambient temperature value is required for specifying convection and radiation boundary conditions.

Data Types: double

Emissivity — Radiation emissivity coefficient

number in the range (0, 1)

Radiation emissivity coefficient, specified as a number in the range (0, 1).

Specify ambient temperature using the AmbientTemperature property and the Stefan-Boltzmann constant using the femodel properties. The value of Emissivity is positive for heat radiation into the ambient environment.

Data Types: double

SurfaceTraction — Normal and tangential distributed forces on boundary

vector | function handle

Normal and tangential distributed forces on the boundary (in the global Cartesian coordinate system), specified as a vector of three elements or a function handle.

If you specify SurfaceTraction as a function handle, the function must return a three-row matrix. Each column of the matrix corresponds to the surface traction vector at the boundary coordinates provided by the solver. For a transient or frequency response analysis, surface traction also can be a function of time or frequency, respectively. For details, see Nonconstant Parameters of Finite Element Model.

Data Types: double | function_handle

TranslationalStiffness — Distributed spring stiffness

vector | function handle

Distributed spring stiffness for each translational direction used to model an elastic foundation, specified as a vector of three elements or a function handle.

If you specify TranslationalStiffness as a function handle, the function must return a three-row matrix. Each column of the matrix corresponds to the stiffness vector at the boundary coordinates provided by the solver. For a transient or frequency response analysis, translational stiffness also can be a function of time or frequency, respectively. For details, see Nonconstant Parameters of Finite Element Model.

Data Types: double | function_handle

Gravity — Acceleration due to gravity

vector

Acceleration due to gravity, specified as a vector of two elements.

Data Types: double

AngularVelocity — Angular velocity for modeling centrifugal loading in an axisymmetric model

positive number

Angular velocity for modeling centrifugal loading in an axisymmetric model, specified as a positive number.

Data Types: double

ChargeDensity — Charge density

real number | function handle

Charge density, specified as a real number or function handle. Use a function handle to specify a charge density that depends on the coordinates. For details, see Nonconstant Parameters of Finite Element Model.

Data Types: double | function_handle

CurrentDensity — Current density

real number | vector | function handle | ConductionResults object

Current density, specified as a real number, vector, function handle, or ConductionResults object. Use a function handle to specify a nonconstant current density. For details, see Nonconstant Parameters of Finite Element Model.

For magnetostatic analysis, the current density must be:

• A real number or a function handle for a 2-D model. The toolbox does not support conduction results as a source of current density for a 2-D magnetostatic analysis.

• A vector of three elements, a ConductionResults object, or a function handle for a 3-D model

For harmonic analysis with an electric field type, the toolbox multiplies the specified current density by -i and by frequency. The current density must be:

• A vector of two elements or a function handle that depends on the coordinates for a 2-D model

• A vector of three elements or a function handle that depends on the coordinates for a 3-D model

For harmonic analysis with a magnetic field type, the toolbox uses the curl of the specified current density. The current density must be:

• A number or a function handle that depends on the coordinates for a 2-D model

• A vector of three elements or a function handle that depends on the coordinates for a 3-D model

Data Types: double | function_handle

Magnetization — Magnetization

vector | function handle

Magnetization, specified as a vector of two elements for a 2-D model, vector of three elements for a 3-D model, or function handle. Use a function handle to specify a magnetization that depends on coordinates. For details, see Nonconstant Parameters of Finite Element Model.

Data Types: double | function_handle

SurfaceCurrentDensity — Surface current density

real number | function handle

Surface current density in the direction normal to the boundary, specified as a real number or function handle. The solver uses a surface current density boundary condition for a DC conduction analysis. Use a function handle to specify a surface current density that depends on the coordinates. For details, see Nonconstant Parameters of Finite Element Model.

Data Types: double | function_handle

Examples

Surface Traction on Specified Boundaries

Specify surface traction for an femodel object representing a static structural problem.

Create and plot a geometry that consists of two nested cylinders.

gm = multicylinder([0.01,0.015],0.05);
pdegplot(gm,FaceLabels="on",FaceAlpha=0.4);

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

model = femodel(AnalysisType="structuralStatic", ...
                Geometry=gm);

Specify the surface traction for faces 2 and 5.

model.FaceLoad([2 5]) = faceLoad(SurfaceTraction=[0 0 100]);
model.FaceLoad([2 5]).SurfaceTraction

ans = 1×3

     0     0   100

ans = 1×3

     0     0   100

Angular Velocity of Spinning Disk

Specify angular velocity for an femodel object representing a static structural problem. For this analysis, simplify the 3-D axisymmetric model to a 2-D model.

Create a rectangular geometry that represents an spinning disk. The inner radius of the disk is 0.05, and the outer radius is 0.2. The thickness of the disk is 0.05.

gm = decsg([3 4 0.05 0.2 0.2 0.05 -0.025 -0.025 0.025 0.025]');

Plot the geometry with the face labels.

pdegplot(gm,FaceLabels="on");
xlim([0.04 0.21])
ylim([-0.03 0.03])

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

model = femodel(AnalysisType="structuralStatic", ...
                Geometry=gm);
model.PlanarType = "axisymmetric";

Apply centrifugal load due to spinning of the disk. Assume that the disk is spinning at 104.7 rad/s.

model.FaceLoad = faceLoad(AngularVelocity=104.7);
model.FaceLoad

ans = 
  1x1 faceLoad array

Properties for analysis type: structuralStatic

Index    Gravity    AngularVelocity    Temperature    Pressure    TranslationalStiffness
  1        []          104.7000            []            []                 []          

  Show all properties

Version History

Introduced in R2023a