StructuralModel

Structural model object

Description

A StructuralModel object contains information about a structural analysis problem: the geometry, material properties, damping parameters, body loads, boundary loads, boundary constraints, superelement interfaces, initial displacement and velocity, and mesh.

Creation

To create a StructuralModel object, use createpde and specify 'structural' as its first argument .

Properties

AnalysisType — Type of structural analysis

'static-solid' | 'static-planestress' | 'static-planestrain' | 'static-axisymmetric' | 'transient-solid' | 'transient-planestress' | 'transient-planestrain' | 'transient-axisymmetric' | 'modal-solid' | 'modal-planestress' | 'modal-planestrain' | 'modal-axisymmetric' | 'frequency-solid' | 'frequency-planestress' | 'frequency-planestrain' | 'frequency-axisymmetric'

Type of structural analysis, specified as one of these values.

Static analysis:

• 'static-solid' for static structural analysis of a solid (3-D) problem

• 'static-planestress' for static structural analysis of a plane-stress problem

• 'static-planestrain' for static structural analysis of a plane-strain problem

• 'static-axisymmetric' for static structural analysis of an axisymmetric (2-D) problem

Transient analysis:

• 'transient-solid' for transient structural analysis of a solid (3-D) problem

• 'transient-planestress' for transient structural analysis of a plane-stress problem

• 'transient-planestrain' for transient structural analysis of a plane-strain problem

• 'transient-axisymmetric' for transient structural analysis of an axisymmetric (2-D) problem

Modal analysis:

• 'modal-solid' for modal analysis of a solid (3-D) problem

• 'modal-planestress' for modal analysis of a plane-stress problem

• 'modal-planestrain' for modal analysis of a plane-strain problem

• 'modal-axisymmetric' for modal analysis of an axisymmetric (2-D) problem

Frequency response analysis:

• 'frequency-solid' for frequency response analysis of a solid (3-D) problem

• 'frequency-planestress' for frequency response analysis of a plane-stress problem

• 'frequency-planestrain' for frequency response analysis of a plane-strain problem

• 'frequency-axisymmetric' for frequency response analysis of an axisymmetric (2-D) problem

To change a structural analysis type, assign a new type to model.AnalysisType. Ensure that all other properties of the model are consistent with the new analysis type. Note that you cannot change the spatial dimensionality. For example, you can change the analysis type from 'static-solid' to 'modal-solid', but cannot change it to 'static-planestress'.

Example: model = createpde('structural','static-solid')

Data Types: char

Geometry — Geometry description

AnalyticGeometry | DiscreteGeometry

Geometry description, specified as AnalyticGeometry for a 2-D geometry or DiscreteGeometry for a 2-D or 3-D geometry.

MaterialProperties — Material properties

StructuralMaterialAssignment object containing material property assignments

Material properties within the domain, specified as a StructuralMaterialAssignment object containing the material property assignments. For details, see StructuralMaterialAssignment Properties.

To create the material properties assignments for your structural analysis model, use the structuralProperties function.

BodyLoads — Loads acting on domain or subdomain

BodyLoadAssignment object containing body load assignments

Loads acting on the domain or subdomain, specified as a BodyLoadAssignment object containing body load assignments. For details, see BodyLoadAssignment Properties.

To create body load assignments for your structural analysis model, use the structuralBodyLoad function.

BoundaryConditions — Structural loads and boundary conditions

StructuralBC object containing boundary condition assignments

Structural loads and boundary conditions applied to the geometry, specified as a StructuralBC object containing the boundary condition assignments. For details, see StructuralBC Properties.

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

DampingModels — Damping model for transient or frequency response analysis

StructuralDampingAssignment object containing damping assignments

Damping model for transient or frequency response analysis, specified as a StructuralDampingAssignment object containing damping assignments. For details, see StructuralDampingAssignment Properties.

To set damping parameters for your structural model, use the structuralDamping function.

ReferenceTemperature — Reference temperature for thermal load

0 (default) | number

Reference temperature for a thermal load, specified as a number. The reference temperature corresponds to state of zero thermal stress of the model. The default 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 static structural model, assign the property value directly, for example, structuralmodel.ReferenceTemperature = 10. To specify the thermal load itself, use the structuralBodyLoad function.

Data Types: double

InitialConditions — Initial displacement and velocity

GeometricStructuralICs object | NodalStructuralICs object

Initial displacement and velocity, specified as a GeometricStructuralICs or NodalStructuralICs object. For details, see GeometricStructuralICs Properties and NodalStructuralICs Properties.

To set initial conditions for your transient structural model, use the structuralIC function.

SuperelementInterfaces — Superelement interfaces for component mode synthesis

StructuralSEIAssignment object containing superelement interfaces assignments

Superelement interfaces for the component mode synthesis, specified as a StructuralSEIAssignment object containing superelement interface assignments. For details, see StructuralSEIAssignment Properties.

To specify superelement interfaces for your frequency response structural model, use the structuralSEInterface function.

Mesh — Mesh for solution

FEMesh object

Mesh for solution, specified as a FEMesh object. For property details, see FEMesh Properties.

To create the mesh, use the generateMesh function.

LinearizeInputs — Inputs for linearized model

structure array

Inputs for a linearized model, specified as a structure array. The inputs are used by the linearize that extracts mechss (Control System Toolbox) model from a structural model.

LinearizeOutputs — Outputs for linearized model

structure array

Inputs for a linearized model, specified as a structure array. The outputs are used by the linearize that extracts mechss (Control System Toolbox) model from a structural model.

SolverOptions — Algorithm options for PDE solvers

PDESolverOptions object

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

Object Functions

geometryFromEdges	Create 2-D geometry from decomposed geometry matrix
geometryFromMesh	Create 2-D or 3-D geometry from mesh
importGeometry	Import geometry from STL or STEP file
structuralBC	Specify boundary conditions for structural model
structuralSEInterface	Specify structural superelement interface for component mode synthesis
structuralBodyLoad	Specify body load for structural model
structuralBoundaryLoad	Specify boundary loads for structural model
structuralIC	Set initial conditions for a transient structural model
structuralProperties	Assign structural properties of material for structural model
solve	Solve structural analysis, heat transfer, or electromagnetic analysis problem
reduce	Reduce structural or thermal model

Examples

Create and Populate Structural Analysis Model

Create a static structural model for solving a solid (3-D) problem.

structuralModel = createpde("structural","static-solid")

structuralModel = 
  StructuralModel with properties:

              AnalysisType: "static-solid"
                  Geometry: []
        MaterialProperties: []
                 BodyLoads: []
        BoundaryConditions: []
      ReferenceTemperature: []
    SuperelementInterfaces: []
                      Mesh: []
             SolverOptions: [1x1 pde.PDESolverOptions]

Create and plot the geometry.

gm = multicuboid(0.5,0.1,0.1);
structuralModel.Geometry = gm;
pdegplot(structuralModel,"FaceAlpha",0.5)

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

structuralProperties(structuralModel,"Cell",1,"YoungsModulus",210E3, ...
                                              "PoissonsRatio",0.3, ...
                                              "MassDensity",2.7E-6)

ans = 
  StructuralMaterialAssignment with properties:

           RegionType: 'Cell'
             RegionID: 1
        YoungsModulus: 210000
        PoissonsRatio: 0.3000
          MassDensity: 2.7000e-06
                  CTE: []
    HystereticDamping: []

Specify the gravity load on the rod.

structuralBodyLoad(structuralModel, ...
    "GravitationalAcceleration",[0;0;-9.8])

ans = 
  BodyLoadAssignment with properties:

                   RegionType: 'Cell'
                     RegionID: 1
    GravitationalAcceleration: [3x1 double]
              AngularVelocity: []
                  Temperature: []
                     TimeStep: []
                        Label: []

Specify that face 6 is a fixed boundary.

structuralBC(structuralModel,"Face",6,"Constraint","fixed")

ans = 
  StructuralBC with properties:

                RegionType: 'Face'
                  RegionID: 6
                Vectorized: 'off'

   Boundary Constraints and Enforced Displacements
              Displacement: []
             XDisplacement: []
             YDisplacement: []
             ZDisplacement: []
                Constraint: "fixed"
                    Radius: []
                 Reference: []
                     Label: []

   Boundary Loads
                     Force: []
           SurfaceTraction: []
                  Pressure: []
    TranslationalStiffness: []
                     Label: []

Specify the surface traction for face 5.

structuralBoundaryLoad(structuralModel, ...
                       "Face",5, ...
                       "SurfaceTraction",[0;0;100])

ans = 
  StructuralBC with properties:

                RegionType: 'Face'
                  RegionID: 5
                Vectorized: 'off'

   Boundary Constraints and Enforced Displacements
              Displacement: []
             XDisplacement: []
             YDisplacement: []
             ZDisplacement: []
                Constraint: []
                    Radius: []
                 Reference: []
                     Label: []

   Boundary Loads
                     Force: []
           SurfaceTraction: [3x1 double]
                  Pressure: []
    TranslationalStiffness: []
                     Label: []

Generate a mesh.

generateMesh(structuralModel)

ans = 
  FEMesh with properties:

             Nodes: [3x7800 double]
          Elements: [10x4857 double]
    MaxElementSize: 0.0208
    MinElementSize: 0.0104
     MeshGradation: 1.5000
    GeometricOrder: 'quadratic'

View the properties of structuralModel.

structuralModel

structuralModel = 
  StructuralModel with properties:

              AnalysisType: "static-solid"
                  Geometry: [1x1 DiscreteGeometry]
        MaterialProperties: [1x1 StructuralMaterialAssignmentRecords]
                 BodyLoads: [1x1 BodyLoadAssignmentRecords]
        BoundaryConditions: [1x1 StructuralBCRecords]
      ReferenceTemperature: []
    SuperelementInterfaces: []
                      Mesh: [1x1 FEMesh]
             SolverOptions: [1x1 pde.PDESolverOptions]

Version History

Introduced in R2017b

R2022a: Hysteretic damping

You can now specify hysteretic damping of a material for direct and modal frequency response models.

R2021b: Sparse linear models for use with Control System Toolbox

StructuralModel now has additional properties, LinearizeInputs and LinearizeOutputs containing inputs and outputs for linearized model. They are used by the linearize that extracts a mechss (Control System Toolbox) model from a structural model.

R2020a: Axisymmetric analysis

You can now specify AnalysisType for axisymmetric models. Axisymmetric analysis simplifies 3-D structural problems to 2-D using their symmetry around the axis of rotation.

R2019b: Reduced-order modeling for structural analysis

The toolbox now supports the frequency response analysis for structural models.

R2019b: Frequency response analysis

You can now specify AnalysisType for frequency response analysis, including 'frequency-solid', 'frequency-planestress', 'frequency-planestrain', and 'frequency-axisymmetric'.

R2018b: Reference temperature for thermal stress

The programmatic workflow for static structural analysis problems now enables you to account for thermal loading. When setting up a static structural problem, you can specify a reference temperature as a property of StructuralModel. This temperature corresponds to the state of the model at which both thermal stress and strain are zeros.

R2018a: Modal analysis

The programmatic workflow for modal analysis problems now enables you to find natural frequencies and mode shapes of a structure. When solving a modal analysis model, the solver requires a frequency range parameter and returns the modal solution in that frequency range. The AnalysisType values for modal analysis are 'modal-solid', 'modal-planestress', 'modal-planestrain', and 'modal-axisymmetric'.

R2018a: Transient analysis

The programmatic workflow for structural analysis problems now enables you to set up, solve, and analyze dynamic linear elasticity problems. The AnalysisType values for transient analysis are 'transient-solid', 'transient-planestress', 'transient-planestrain', and 'transient-axisymmetric'.