faceLoad
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
Description
model.FaceLoad(
creates a FaceID
) = faceLoad(Name=Value)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
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