artisynth.core.materials

Class Blankevoort1991AxialLigament

java.lang.Object

artisynth.core.materials.MaterialBase

artisynth.core.materials.AxialMaterial

artisynth.core.materials.Blankevoort1991AxialLigament

All Implemented Interfaces:

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

public class Blankevoort1991AxialLigament
extends AxialMaterial

Ligmament material based on : Blankevoort, L., and Huiskes, R. (1991). Ligament-bone interaction in a three-dimensional model of the knee. Journal of Biomechanical Engineering, 113(3), 263-269. implementation adapted from UW SimTk plugin: https://simtk.org/home/uwmodels z * Notes: - the restLength property in the associated spring is used as the referenceLength in the UW formulation, where referenceLength is the length of the ligament when the joint is in the reference position (full extension).

Field Summary

Fields

Modifier and Type	Field and Description
static double	DEFAULT_DAMPING
static double	DEFAULT_LINEAR_STIFFNESS
static double	DEFAULT_SLACK_LENGTH
static double	DEFAULT_TRANSITION_STRAIN
static PropertyList	myProps

Constructor Summary

Constructors

Constructor and Description
Blankevoort1991AxialLigament()
Blankevoort1991AxialLigament(double stiffness, double slackLen, double damping)

Method Summary

Modifier and Type	Method and Description
Blankevoort1991AxialLigament	clone() Returns a clone of this composite property.
double	computeDFdl(double l, double ldot, double l0, double excitation) Computes and returns the derivative of the axial spring tension with respect to the length.
double	computeDFdldot(double l, double ldot, double l0, double excitation) Computes and returns the derivative of the axial spring tension with respect to the length time derivative.
double	computeF(double l, double ldot, double l0, double excitation) Computes and returns the axial spring tension, as a function of length, length time derivative, rest length, and excitation.
boolean	equals(AxialMaterial mat)
PropertyList	getAllPropertyInfo() Returns a list giving static information about all properties exported by this object.
double	getDamping()
double	getLinearStiffness()
double	getSlackLength()
double	getTransitionStrain()
boolean	isDFdldotZero() Returns true if computeDFdldot() always returns zero.
void	scaleDistance(double s) Scales all distance coordinates.
void	scaleMass(double s) Scales all mass units.
void	setDamping(double d)
void	setLinearStiffness(double linearStiffness)
void	setSlackLength(double sl)
void	setTransitionStrain(double e)

Methods inherited from class artisynth.core.materials.AxialMaterial

equals, getSubClasses

Methods inherited from class artisynth.core.materials.MaterialBase

advanceState, createStateObject, getProperty, getPropertyHost, getPropertyInfo, hasProperty, hasState, hasSymmetricTangent, isWritable, postscan, scan, setPropertyHost, setPropertyInfo, symmetryOrStateChanged, updateMaterial, write, writeItems

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_LINEAR_STIFFNESS

public static double DEFAULT_LINEAR_STIFFNESS

DEFAULT_TRANSITION_STRAIN

public static double DEFAULT_TRANSITION_STRAIN

DEFAULT_DAMPING

public static double DEFAULT_DAMPING

DEFAULT_SLACK_LENGTH

public static double DEFAULT_SLACK_LENGTH

myProps

public static PropertyList myProps

Constructor Detail

Blankevoort1991AxialLigament

public Blankevoort1991AxialLigament()

Blankevoort1991AxialLigament

public Blankevoort1991AxialLigament(double stiffness,
                                    double slackLen,
                                    double damping)

Method Detail

getAllPropertyInfo

public PropertyList getAllPropertyInfo()

Description copied from interface: HasProperties

Returns a list giving static information about all properties exported by this object.

Specified by:

getAllPropertyInfo in interface HasProperties

Overrides:

getAllPropertyInfo in class MaterialBase

Returns:

static information for all exported properties

computeF

public double computeF(double l,
                       double ldot,
                       double l0,
                       double excitation)

Description copied from class: AxialMaterial

Computes and returns the axial spring tension, as a function of length, length time derivative, rest length, and excitation.

Specified by:

computeF in class AxialMaterial

Parameters:

l - spring length

ldot - spring length time derivative

l0 - spring rest length

excitation - excitation value (varying from 0 to 1)

Returns:

spring tension

computeDFdl

public double computeDFdl(double l,
                          double ldot,
                          double l0,
                          double excitation)

Description copied from class: AxialMaterial

Computes and returns the derivative of the axial spring tension with respect to the length.

Specified by:

computeDFdl in class AxialMaterial

Parameters:

l - spring length

ldot - spring length time derivative

l0 - spring rest length

excitation - excitation value (varying from 0 to 1)

Returns:

tension derivative with respect to length

computeDFdldot

public double computeDFdldot(double l,
                             double ldot,
                             double l0,
                             double excitation)

Description copied from class: AxialMaterial

Computes and returns the derivative of the axial spring tension with respect to the length time derivative.

Specified by:

computeDFdldot in class AxialMaterial

Parameters:

l - spring length

ldot - spring length time derivative

l0 - spring rest length

excitation - excitation value (varying from 0 to 1)

Returns:

tension derivative with respect to length time derivative

isDFdldotZero

public boolean isDFdldotZero()

Description copied from class: AxialMaterial

Returns true if computeDFdldot() always returns zero. For a linear spring, this simply means the damping is zero. When dFdldot is always 0, then stiffness matrix will be symmetric.

Specified by:

isDFdldotZero in class AxialMaterial

getLinearStiffness

public double getLinearStiffness()

setLinearStiffness

public void setLinearStiffness(double linearStiffness)

getTransitionStrain

public double getTransitionStrain()

setTransitionStrain

public void setTransitionStrain(double e)

getDamping

public double getDamping()

setDamping

public void setDamping(double d)

getSlackLength

public double getSlackLength()

setSlackLength

public void setSlackLength(double sl)

equals

public boolean equals(AxialMaterial mat)

Overrides:

equals in class AxialMaterial

clone

public Blankevoort1991AxialLigament clone()

Description copied from interface: CompositeProperty

Returns a clone of this composite property.

Specified by:

clone in interface CompositeProperty

Specified by:

clone in interface Clonable

Overrides:

clone in class AxialMaterial

Returns:

clone of this property

scaleDistance

public void scaleDistance(double s)

Description copied from interface: ScalableUnits

Scales all distance coordinates.

Specified by:

scaleDistance in interface ScalableUnits

Overrides:

scaleDistance in class MaterialBase

Parameters:

s - scaling factor

scaleMass

public void scaleMass(double s)

Description copied from interface: ScalableUnits

Scales all mass units.

Specified by:

scaleMass in interface ScalableUnits

Overrides:

scaleMass in class MaterialBase

Parameters:

s - scaling factor