StructuralBC Properties

Boundary condition or boundary load for structural analysis model

A StructuralBC object specifies the type of PDE boundary condition or boundary load on a set of geometry boundaries. A StructuralModel object contains a vector of StructuralBC objects in its BoundaryConditions.StructuralBCAssignments property.

To specify boundary conditions for your model, use the structuralBC function. To specify boundary loads, use structuralBoundaryLoad.

Properties of StructuralBC

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Geometric region type, returned as 'Face' for a 3-D geometry or 'Edge' for a 2-D geometry.

Data Types: char | string

Geometric region ID, returned as a vector of positive integers. Find the region IDs by using pdegplot with 'FaceLabels' (3-D) or 'EdgeLabels' (2-D) set to 'on'.

Data Types: double

Vectorized function evaluation, returned as 'off' or 'on'. This evaluation applies when you pass a function handle as an argument. To save time in the function handle evaluation, specify 'on', assuming that your function handle computes in a vectorized fashion. See Vectorization (MATLAB). For details on this evaluation, see Nonconstant Boundary Conditions.

Data Types: char

Boundary Constraints and Enforced Displacements

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Enforced displacement, returned as a numeric vector or function handle. The numeric vector must contain two elements for a 2-D model and three elements for a 3-D model. The function must return a two-row matrix for a 2-D model and a three-row matrix for a 3-D model. Each column of the matrix must correspond to the enforced displacement vector at the boundary coordinates provided by the solver.

Data Types: double | function_handle

x-component of the enforced displacement, returned as a number or function handle. The function must return a row vector. Each column of the vector must correspond to the value of the x-component of the enforced displacement at the boundary coordinates provided by the solver.

Data Types: double | function_handle

y-component of the enforced displacement, returned as a number or function handle. The function must return a row vector. Each column of the vector must correspond to the value of the y-component of the enforced displacement at the boundary coordinates provided by the solver.

Data Types: double | function_handle

z-component of the enforced displacement, returned as a number or function handle. The function must return a row vector. Each column of the vector must correspond to the value of the z-component of the enforced displacement at the boundary coordinates provided by the solver.

Data Types: double | function_handle

Standard structural boundary constraints, returned as 'free','fixed','roller', 'symmetric', or 'multipoint'.

Data Types: char

Radius of a circle (for a 2-D geometry) or a sphere (for a 3-D geometry) around the reference point location for the multipoint constraint, returned as a positive number.

Data Types: double

Reference point location for the multipoint constraint, returned as a 2-by-1 (for a 2-D geometry) or 3-by-1 (for a 3-D geometry) numeric vector.

Data Types: double

Boundary Loads

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Concentrated force at a vertex, returned as a numeric vector or function handle.

Data Types: double | function_handle

Normal and tangential distributed forces on the boundary (in the global Cartesian coordinates system), returned as a numeric vector or function handle. The numeric vector must contain two elements for a 2-D model and three elements for a 3-D model. The function must return a two-row matrix for a 2-D model and a three-row matrix for a 3-D model. Each column of the matrix must correspond to the surface traction vector at the boundary coordinates provided by the solver.

Data Types: double | function_handle

Pressure normal to the boundary, returned as a number or function handle. The function must return a row vector in which each column corresponds to the value of pressure at the boundary coordinates provided by the solver. A positive value of pressure acts in the direction of the outward normal to the boundary.

Data Types: double | function_handle

Distributed spring stiffness for each translational direction used to model an elastic foundation, returned as a numeric vector or function handle. The numeric vector must contain two elements for a 2-D model and three elements for a 3-D model. The custom function must return a two-row matrix for a 2-D model and a three-row matrix for a 3-D model. Each column of this matrix corresponds to the stiffness vector at the boundary coordinates provided by the solver.

Data Types: double | function_handle

Time Variation of Force, Pressure, or Enforced Displacement

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Start time for a displacement component, the pressure, or the concentrated force load, returned as a nonnegative number.

Data Types: double

End time for a displacement component, the pressure, or the concentrated force load, returned as a nonnegative number.

Data Types: double

Rise time for a displacement component, the pressure, or the concentrated force load, returned as a nonnegative number.

Data Types: double

Fall time for a displacement component, the pressure, or the concentrated force load, returned as a nonnegative number.

Data Types: double

Sinusoidal Variation of Force, Pressure, or Enforced Displacement

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Frequency of a sinusoidal displacement component, the sinusoidal pressure, or the concentrated force, returned as a positive number, in radians per unit of time.

Data Types: double

Phase of a sinusoidal displacement component, the sinusoidal pressure, or the concentrated force, returned as a nonnegative number, in radians per unit of time.

Data Types: double

Introduced in R2017b