artisynth.core.materials

Class NullMaterial

java.lang.Object

artisynth.core.materials.MaterialBase

artisynth.core.materials.FemMaterial

artisynth.core.materials.NullMaterial

All Implemented Interfaces:

HasMaterialState, PostScannable, PropertyChangeListener, ScalableUnits, java.lang.Cloneable, CompositeProperty, HasProperties, Clonable, Scannable

public class NullMaterial
extends FemMaterial

Field Summary

Fields inherited from class artisynth.core.materials.FemMaterial

myProps

Constructor Summary

Constructors

Constructor and Description
NullMaterial()

Method Summary

Modifier and Type	Method and Description
double	computeStrainEnergyDensity(DeformedPoint def, Matrix3d Q, double excitation, MaterialStateObject state) Computes the current strain energy density.
void	computeStressAndTangent(SymmetricMatrix3d sigma, Matrix6d D, DeformedPoint def, Matrix3d Q, double excitation, MaterialStateObject state) Computes the current Cauchy stress and tangent stiffness matrix.
boolean	isCorotated() Deformation is computed by first removing a rotation component (either explicit or computed from strain)
boolean	isInvertible() Returns true if this material is defined for a deformation gradient with a non-positive determinant.
boolean	isLinear() Linear stress/stiffness response to deformation, allows tangent to be pre-computed and stored.
boolean	isThreadSafe() Queries whether this material's stress, tangent and energy methods can be called concurrently from multiple threads (for different deformed points).

Methods inherited from class artisynth.core.materials.FemMaterial

cauchyToSecondPKStress, clone, collectFieldBindings, computeDevLeftCauchyGreen, computeDevRightCauchyGreen, computeLeftCauchyGreen, computeRightCauchyGreen, createStateObject, equals, getAllPropertyInfo, getIncompressibleComponent, getSubClasses, hasState, isIncompressible, propertyChanged, registerSubclass, secondPKToCauchyStress, writeItems

Methods inherited from class artisynth.core.materials.MaterialBase

advanceState, createChangeEvent, getProperty, getPropertyHost, getPropertyInfo, hasProperty, hasSymmetricTangent, isWritable, postscan, scaleDistance, scaleMass, scan, setPropertyHost, setPropertyInfo, symmetryOrStateChanged, updateMaterial, write

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

NullMaterial

public NullMaterial()

Method Detail

computeStressAndTangent

public void computeStressAndTangent(SymmetricMatrix3d sigma,
                                    Matrix6d D,
                                    DeformedPoint def,
                                    Matrix3d Q,
                                    double excitation,
                                    MaterialStateObject state)

Computes the current Cauchy stress and tangent stiffness matrix.

Specified by:

computeStressAndTangent in class FemMaterial

Parameters:

sigma - returns the Cauchy stress

D - optional; if non-null, returns the tangent matrix

def - deformation information, including deformation gradient and pressure

Q - coordinate frame specifying directions of anisotropy

excitation - current excitation value

state - material state information, or null if the material does not have state.

computeStrainEnergyDensity

public double computeStrainEnergyDensity(DeformedPoint def,
                                         Matrix3d Q,
                                         double excitation,
                                         MaterialStateObject state)

Description copied from class: FemMaterial

Computes the current strain energy density.

Specified by:

computeStrainEnergyDensity in class FemMaterial

Parameters:

def - deformation information, including deformation gradient and pressure

Q - coordinate frame specifying directions of anisotropy

excitation - current excitation value

state - material state information, or null if the material does not have state.

Returns:

strain energy density

isInvertible

public boolean isInvertible()

Description copied from class: FemMaterial

Returns true if this material is defined for a deformation gradient with a non-positive determinant.

Overrides:

isInvertible in class FemMaterial

isLinear

public boolean isLinear()

Description copied from class: FemMaterial

Linear stress/stiffness response to deformation, allows tangent to be pre-computed and stored.

Overrides:

isLinear in class FemMaterial

Returns:

true if linear response

isCorotated

public boolean isCorotated()

Description copied from class: FemMaterial

Deformation is computed by first removing a rotation component (either explicit or computed from strain)

Overrides:

isCorotated in class FemMaterial

Returns:

true if material is corotated

isThreadSafe

public boolean isThreadSafe()

Description copied from class: FemMaterial

Queries whether this material's stress, tangent and energy methods can be called concurrently from multiple threads (for different deformed points). This requires that the methods do not modify any shared internal state. The default implementation returns false; subclasses which are thread safe should override this. If the material has properties bound to fields (see FemMaterial.collectFieldBindings(java.util.List<artisynth.core.modelbase.FieldComponent>)), then concurrent use additionally requires that FieldComponent.updateForConcurrentAccess() has been called for each of those fields.

Overrides:

isThreadSafe in class FemMaterial

Returns:

true if this material is thread safe