Elasto-plastic rod material implementing yield conditions with isotropic and kinematic hardening. More...

#include "ElastoPlasticRodMaterial.h"

Inheritance diagram for ElastoPlasticRodMaterial:

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Collaboration diagram for ElastoPlasticRodMaterial:

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Public Types
enum	YieldType { EXPRESSION , SUPER_ELLIPSE }
	Yield condition implementations, selected by the property `yieldType` More...

Public Member Functions
	ElastoPlasticRodMaterial (const String &name, const Properties &conf, const Properties &props, const Properties &globdat)
	Constructor with plasticity configuration.

virtual void	configure (const Properties &props, const Properties &globdat) override
	Configure plasticity parameters and yield conditions.

virtual void	getConfig (const Properties &conf, const Properties &globdat) const override
	Retrieve current material configuration.

virtual void	getHardVals (const Vector &hardVals, const Vector &hardParams) const
	Get hardening values from hardening parameters.

virtual void	getStress (const Vector &stress, const Vector &strain) override
	Elastic stress computation based on elastic rod material model.

virtual void	getStress (const Vector &stress, const Vector &strain, const idx_t &ielem, const idx_t &ip, const bool inelastic=true) override
	Plastic stress computation using convex cutting plane algorithm.

virtual void	applyDeform () override
	Apply computed deformation to the material state.

virtual void	rejectDeform () override
	Reject the current deformation and revert to previous state.

virtual void	getTable (XTable &strain_table, const Vector &weights, const String &name, const IdxVector &items) const override
	Populate strain table with material-specific data.

virtual double	getDissipatedEnergy (const idx_t &ielem, const idx_t &ip) const override
	Get the dissipated energy at a specific integration point.

virtual double	getHardeningPotential (const idx_t &ielem, const idx_t &ip) const override
	Get the hardening potential energy at a specific integration point.

virtual double	getPotentialEnergy (const idx_t &ielem, const idx_t &ip) const override
	Get the potential energy at a specific integration point.

Public Member Functions inherited from ElasticRodMaterial
	ElasticRodMaterial (const String &name, const Properties &conf, const Properties &props, const Properties &globdat)
	Constructor with configuration and global data.

virtual Matrix	getMaterialStiff () const override
	Get the material stiffness matrix.

virtual Matrix	getMaterialStiff (const idx_t &ielem, const idx_t &ip) const override
	Get the material stiffness matrix for specific element and integration point.

virtual void	getMaterialStiff (const Matrix &stiff) const override
	Write the material stiffness matrix into an existing matrix (no allocation, for hot code)

virtual void	getMaterialStiff (const Matrix &stiff, const idx_t &ielem, const idx_t &ip) const override
	Write the material stiffness matrix for an element and integration point into an existing matrix.

virtual Matrix	getMaterialMass () const override
	Get the material mass matrix per unit length.

virtual Matrix	getMaterialMass (const idx_t &ielem, const idx_t &ip) const override
	Get the material mass matrix for specific element and integration point.

virtual void	getMaterialMass (const Matrix &mass) const override
	Write the material mass matrix per unit length into an existing matrix (no allocation, for hot code)

virtual void	getMaterialMass (const Matrix &mass, const idx_t &ielem, const idx_t &ip) const override
	Write the material mass matrix for an element and integration point into an existing matrix.

virtual Matrix	getLumpedMass (const double l) const override
	Get the lumped mass matrix for a given element length.

virtual Matrix	getLumpedMass (const double l, const idx_t &ielem) const override
	Get the lumped mass matrix for specific element and length.

Public Member Functions inherited from Material
	Material (const String &name, const Properties &conf, const Properties &props, const Properties &globdat)
	Constructs a new Material object.

virtual String	getContext () const override
	Get the context string for error reporting and debugging.

Static Public Member Functions
static Ref< Material >	makeNew (const String &name, const Properties &conf, const Properties &props, const Properties &globdat)
	Factory method for plastic material creation.

static void	declare ()
	Register plastic material type with factory.

Static Public Member Functions inherited from ElasticRodMaterial
static Ref< Material >	makeNew (const String &name, const Properties &conf, const Properties &props, const Properties &globdat)
	Factory method for material creation.

static void	declare ()
	Register material type with factory.

Static Public Attributes
Plasticity property identifiers
static const char *	TYPE_NAME = "ElastoPlasticRod"

static const char *	YIELD_PROP = "yieldCond"
	Yield condition function.

static const char *	YIELD_DERIV_PROP = "yieldDeriv"
	Yield condition derivatives.

static const char *	YIELD_TYPE_PROP = "yieldType"
	Yield condition type (see YieldType)

static const char *	YIELD_STRENGTH_PROP = "yieldStrength"
	Strengths c_i of the super-ellipse yield condition.

static const char *	YIELD_EXPONENT_PROP = "yieldExponent"
	Exponents p_i of the super-ellipse yield condition.

static const char *	ISO_HARD_PROP = "isotropicCoefficient"
	Isotropic hardening parameters.

static const char *	KIN_HARD_PROP = "kinematicTensor"
	Kinematic hardening parameters.

Static Public Attributes inherited from ElasticRodMaterial
static const char *	TYPE_NAME = "ElasticRod"

static const char *	STIFF_PREFIX = "C_"
	Prefix for direct stiffness-matrix input.

static const char *	YOUNGS_MODULUS = "young"
	Young's modulus property key.

static const char *	SHEAR_MODULUS = "shear_modulus"
	Shear modulus property key.

static const char *	POISSON_RATIO = "poisson_ratio"
	Poisson's ratio property key.

static const char *	AREA = "area"
	Cross-sectional area property key.

static const char *	DENSITY = "density"
	Material density property key.

static const char *	AREA_MOMENT = "area_moment"
	Area moment of inertia property key.

static const char *	SHEAR_FACTOR = "shear_correction"
	Shear correction factor property key.

static const char *	POLAR_MOMENT = "polar_moment"
	Polar moment of inertia property key.

static const char *	CROSS_SECTION = "cross_section"
	Cross-section type property key (e.g., "square", "circle" "rectangle")

static const char *	RADIUS = "radius"
	Radius for circular sections property key.

static const char *	SIDE_LENGTH = "side_length"
	Side lengths for rectangular sections property key.

static const char *	N_ELEM = "elemCount"
	Number of elements property key.

static const char *	EDGE_FACTOR = "edge_factor"
	Edge factor f property key: edge elements get stiffness blocks scaled by f^2, f^3, f^4 and mass blocks by (2-f)^2, (2-f)^3, (2-f)^4.

static const char *	EDGE_ELEMS = "edge_elements"
	Number of edge elements property key.

Static Public Attributes inherited from Material
static const char *	VERBOSITY_PROP = "verbosity"
	Property name for verbosity level control.

Protected Member Functions
	~ElastoPlasticRodMaterial ()
	Destroy the elasto-plastic rod material.

double	getYield_ (const Vector &args) const
	Value of the yield condition.

void	getYieldGrad_ (const Vector &grad, const Vector &args) const
	Gradient of the yield condition with respect to args.

double	getSuperEllipse_ (const Vector &args) const
	Super-ellipse yield condition f = sum_i \|s_i/(c_i-h_i)\|^p_i - (1+h_0)

void	getSuperEllipseGrad_ (const Vector &grad, const Vector &args) const
	Gradient of the super-ellipse yield condition (zero stress derivative for \|s_i\| < EPS)

Protected Member Functions inherited from ElasticRodMaterial
	~ElasticRodMaterial ()
	Destroy the elastic rod material.

void	calcMaterialStiff_ ()
	Calculate material stiffness matrix.

void	calcMaterialMass_ ()
	Calculate material mass matrix.

Protected Member Functions inherited from Material
virtual	~Material ()
	Destroy the Material object.

Protected Attributes
Matrix	currDeltaFlow_
	Current plastic flow increment.

Matrix	energyDiss_
	Dissipated energy storage.

Matrix	energyHardPot_
	Hardening potential energy storage.

Plasticity algorithm components
Ref< Function >	yieldCond_
	Yield condition function.

FuncUtils::FuncArray	yieldDeriv_
	Derivatives of yield condition.

idx_t	maxIter_
	Max iterations for stress update.

double	precision_
	Convergence tolerance for stress update.

YieldType	yieldType_
	Selected yield condition implementation.

bool	isoHard_
	Isotropic hardening stress is a yield function argument.

bool	kinHard_
	Kinematic hardening stresses are yield function arguments.

Vector	yieldStrength_
	Strengths c_i of the super-ellipse yield condition.

Vector	yieldExponent_
	Exponents p_i of the super-ellipse yield condition.

Function argument organization
idx_t	dofCount_
	Degrees of freedom in stress/strain vectors.

idx_t	argCount_
	Total arguments to yield condition.

Hardening and plastic state
Matrix	materialH_
	Hardening matrix.

Cubix	oldHardParams_
	Hardening parameters from last converged step.

Cubix	currHardParams_
	Current hardening parameters.

Cubix	oldPlastStrains_
	Plastic strains from last converged step.

Cubix	currPlastStrains_
	Current plastic strains.

Cubix	oldStresses_
	Elastic stresses from last converged step (set in applyDeform)

Work arrays of getStress
Created once in configure and overwritten in every call, so that getStress does not have to create new arrays for every integration point (see the note in utils/helpers.h). Not thread safe.
Vector	plastStrain_
	Plastic strain iterate.

Vector	hardParams_
	Hardening parameter iterate.

Vector	hardStress_
	Hardening stresses.

Vector	elasticStrain_
	Elastic strain.

Vector	yieldArgs_
	Arguments of the yield condition.

Vector	yieldGrad_
	Gradient of the yield condition.

Protected Attributes inherited from ElasticRodMaterial
double	young_
	Young's modulus.

double	shearMod_
	Shear modulus.

double	shearParam_
	Shear parameter.

double	edgeFact_
	Edge factor for lattice materials.

idx_t	edgeElems_
	Number of edge elements.

idx_t	nElem_
	Total number of elements.

double	area_
	Cross-sectional area.

Vector	areaMoment_
	Area moments of inertia.

double	polarMoment_
	Polar moment of inertia.

String	crossSection_
	Cross-section type identifier.

double	radius_
	Radius for circular sections.

Vector	sideLength_
	Side lengths for rectangular sections.

double	density_
	Material density.

Matrix	materialK_
	Material stiffness matrix.

Matrix	materialM_
	Material mass matrix.

Cubix	oldStrains_
	Strains from last converged step.

Cubix	currStrains_
	Strains from current iteration.

Matrix	energyPot_
	Potential energy storage.

jem::numeric::MatmulChain< double, 1 >	matvec_

Matrix	stiffWork_
	Work array for the stiffness in getStress and applyDeform.

String	rodName_
	Material instance name.

Protected Attributes inherited from Material
idx_t	verbosity_
	Verbosity level for material output and debugging.

Detailed Description

See also: Corresponding Paper

Member Enumeration Documentation

◆ YieldType

enum ElastoPlasticRodMaterial::YieldType

Enumerator
EXPRESSION	"Expression": interpreted function `yieldCond` (default)
SUPER_ELLIPSE	"SuperEllipse": native Lamé curve, see getSuperEllipse_

Constructor & Destructor Documentation

◆ ElastoPlasticRodMaterial()

ElastoPlasticRodMaterial::ElastoPlasticRodMaterial	(	const String &	name,
		const Properties &	conf,
		const Properties &	props,
		const Properties &	globdat
	)

Parameters

[in]	name	Material instance name
[out]	conf	Actually used configuration properties
[in]	props	User-specified material properties
[in]	globdat	Global data container

◆ ~ElastoPlasticRodMaterial()

ElastoPlasticRodMaterial::~ElastoPlasticRodMaterial ( )

protected

Member Function Documentation

◆ applyDeform()

void ElastoPlasticRodMaterial::applyDeform ( )

overridevirtual

This method commits the current deformation state to the material's internal variables. It's typically called at the end of a successful load step to update the material's permanent state.

Reimplemented from ElasticRodMaterial.

◆ configure()

void ElastoPlasticRodMaterial::configure	(	const Properties &	props,
		const Properties &	globdat
	)

overridevirtual

Parameters

[in]	props	Properties containing configuration parameters
[in]	globdat	Global data container with simulation context

Exceptions

jem::util::PropertyException if yield function is not provided

Reimplemented from ElasticRodMaterial.

◆ declare()

void ElastoPlasticRodMaterial::declare ( )

static

◆ getConfig()

void ElastoPlasticRodMaterial::getConfig	(	const Properties &	conf,
		const Properties &	globdat
	)		const

overridevirtual

Parameters

[out]	conf	Properties object to store configuration in
[in]	globdat	Global data container with simulation context

Reimplemented from ElasticRodMaterial.

◆ getDissipatedEnergy()

double ElastoPlasticRodMaterial::getDissipatedEnergy	(	const idx_t &	ielem,
		const idx_t &	ip
	)		const

overridevirtual

Computes the energy dissipated through inelastic processes at the specified element and integration point location.

Parameters

[in]	ielem	Element index
[in]	ip	Integration point index within the element

Returns: Total dissipated energy at the specified location

Note: Contract: must return the value of the last committed state, i.e. it has to be stored in applyDeform(). SpecialCosseratRodModel::getEnergies_ reads it right after applyDeform() without re-evaluating strains/stresses.

Reimplemented from ElasticRodMaterial.

◆ getHardeningPotential()

double ElastoPlasticRodMaterial::getHardeningPotential	(	const idx_t &	ielem,
		const idx_t &	ip
	)		const

overridevirtual

Computes the energy stored in hardening variables for plasticity models. This represents the energy associated with the evolution of the yield surface.

Parameters

[in]	ielem	Element index
[in]	ip	Integration point index within the element

Returns: Hardening potential energy at the specified location

Reimplemented from ElasticRodMaterial.

◆ getHardVals()

void ElastoPlasticRodMaterial::getHardVals	(	const Vector &	hardVals,
		const Vector &	hardParams
	)		const

virtual

Parameters

[out]	hardVals	Computed hardening values
[in]	hardParams	Hardening parameters

◆ getPotentialEnergy()

double ElastoPlasticRodMaterial::getPotentialEnergy	(	const idx_t &	ielem,
		const idx_t &	ip
	)		const

overridevirtual

Computes the stored elastic energy at the specified element and integration point location.

Parameters

[in]	ielem	Element index
[in]	ip	Integration point index within the element

Returns: Elastic potential energy at the specified location

Note: Contract: must return the value of the last committed state, i.e. it has to be stored in applyDeform(). SpecialCosseratRodModel::getEnergies_ reads it right after applyDeform() without re-evaluating strains/stresses.; 0 for purely elastic materials

Reimplemented from ElasticRodMaterial.

◆ getStress() [1/2]

void ElastoPlasticRodMaterial::getStress	(	const Vector &	stress,
		const Vector &	strain
	)

overridevirtual

Exceptions

jem::Exception as this method should not be called directly for elasto-plastic materials

Reimplemented from ElasticRodMaterial.

◆ getStress() [2/2]

void ElastoPlasticRodMaterial::getStress	(	const Vector &	stress,
		const Vector &	strain,
		const idx_t &	ielem,
		const idx_t &	ip,
		const bool	inelastic = `true`
	)

overridevirtual

Implements iterative return mapping with yield condition evaluation

Parameters

[out]	stress	Calculated stress vector
[in]	strain	Input strain vector
[in]	ielem	Element index
[in]	ip	Integration point index
[in]	inelastic	Whether to compute the inelastic stress update

See also: Computational Inelasticity Box 3.6

Reimplemented from ElasticRodMaterial.

◆ getSuperEllipse_()

double ElastoPlasticRodMaterial::getSuperEllipse_ ( const Vector & args ) const

protected

Kinematic hardening h_i shifts the strengths c_i (Herrnböck et al., Comput. Mech. 2023, Eq. 39), isotropic hardening h_0 acts on the sum (Herrnböck et al., Comput. Mech. 2021, Eq. 47).

◆ getSuperEllipseGrad_()

void ElastoPlasticRodMaterial::getSuperEllipseGrad_	(	const Vector &	grad,
		const Vector &	args
	)		const

protected

◆ getTable()

void ElastoPlasticRodMaterial::getTable	(	XTable &	strain_table,
		const Vector &	weights,
		const String &	name,
		const IdxVector &	items
	)		const

overridevirtual

This method fills an XTable with strain-related data for output or post-processing purposes. The specific data depends on the material type.

Parameters

[out]	strain_table	Output table to populate with strain data
[in,out]	weights	Weight vector for data averaging or integration
[in]	name	Name identifier for the table data
[in]	items	Index vector specifying which items to include

Reimplemented from ElasticRodMaterial.

◆ getYield_()

double ElastoPlasticRodMaterial::getYield_ ( const Vector & args ) const

protected

Parameters

[in] args Stresses, [isotropic hardening stress], [kinematic hardening stresses]

◆ getYieldGrad_()

void ElastoPlasticRodMaterial::getYieldGrad_	(	const Vector &	grad,
		const Vector &	args
	)		const

protected

Parameters

[out]	grad	Gradient
[in]	args	Stresses, [isotropic hardening stress], [kinematic hardening stresses]

◆ makeNew()

Ref< Material > ElastoPlasticRodMaterial::makeNew	(	const String &	name,
		const Properties &	conf,
		const Properties &	props,
		const Properties &	globdat
	)

static

Parameters

[in]	name	Material instance name
[out]	conf	Actually used configuration properties
[in]	props	User-specified material properties
[in]	globdat	Global data container

Returns: Reference to the created material

◆ rejectDeform()

void ElastoPlasticRodMaterial::rejectDeform ( )

overridevirtual

This method reverts the material to its state before the current load step. It's called when a load step fails to converge or needs to be repeated.

Reimplemented from ElasticRodMaterial.

Member Data Documentation

◆ argCount_

idx_t ElastoPlasticRodMaterial::argCount_

protected

◆ currDeltaFlow_

Matrix ElastoPlasticRodMaterial::currDeltaFlow_

protected

◆ currHardParams_

Cubix ElastoPlasticRodMaterial::currHardParams_

protected

◆ currPlastStrains_

Cubix ElastoPlasticRodMaterial::currPlastStrains_

protected

◆ dofCount_

idx_t ElastoPlasticRodMaterial::dofCount_

protected

◆ elasticStrain_

Vector ElastoPlasticRodMaterial::elasticStrain_

protected

◆ energyDiss_

Matrix ElastoPlasticRodMaterial::energyDiss_

protected

◆ energyHardPot_

Matrix ElastoPlasticRodMaterial::energyHardPot_

protected

◆ hardParams_

Vector ElastoPlasticRodMaterial::hardParams_

protected

◆ hardStress_

Vector ElastoPlasticRodMaterial::hardStress_

protected

◆ ISO_HARD_PROP

const char * ElastoPlasticRodMaterial::ISO_HARD_PROP = "isotropicCoefficient"

static

◆ isoHard_

bool ElastoPlasticRodMaterial::isoHard_

protected

◆ KIN_HARD_PROP

const char * ElastoPlasticRodMaterial::KIN_HARD_PROP = "kinematicTensor"

static

◆ kinHard_

bool ElastoPlasticRodMaterial::kinHard_

protected

◆ materialH_

Matrix ElastoPlasticRodMaterial::materialH_

protected

◆ maxIter_

idx_t ElastoPlasticRodMaterial::maxIter_

protected

◆ oldHardParams_

Cubix ElastoPlasticRodMaterial::oldHardParams_

protected

◆ oldPlastStrains_

Cubix ElastoPlasticRodMaterial::oldPlastStrains_

protected

◆ oldStresses_

Cubix ElastoPlasticRodMaterial::oldStresses_

protected

◆ plastStrain_

Vector ElastoPlasticRodMaterial::plastStrain_

protected

◆ precision_

double ElastoPlasticRodMaterial::precision_

protected

◆ TYPE_NAME

const char * ElastoPlasticRodMaterial::TYPE_NAME = "ElastoPlasticRod"

static

◆ YIELD_DERIV_PROP

const char * ElastoPlasticRodMaterial::YIELD_DERIV_PROP = "yieldDeriv"

static

◆ YIELD_EXPONENT_PROP

const char * ElastoPlasticRodMaterial::YIELD_EXPONENT_PROP = "yieldExponent"

static

◆ YIELD_PROP

const char * ElastoPlasticRodMaterial::YIELD_PROP = "yieldCond"

static

◆ YIELD_STRENGTH_PROP

const char * ElastoPlasticRodMaterial::YIELD_STRENGTH_PROP = "yieldStrength"

static

◆ YIELD_TYPE_PROP

const char * ElastoPlasticRodMaterial::YIELD_TYPE_PROP = "yieldType"

static

◆ yieldArgs_

Vector ElastoPlasticRodMaterial::yieldArgs_

protected

◆ yieldCond_

Ref<Function> ElastoPlasticRodMaterial::yieldCond_

protected

◆ yieldDeriv_

FuncUtils::FuncArray ElastoPlasticRodMaterial::yieldDeriv_

protected

◆ yieldExponent_

Vector ElastoPlasticRodMaterial::yieldExponent_

protected

◆ yieldGrad_

Vector ElastoPlasticRodMaterial::yieldGrad_

protected

◆ yieldStrength_

Vector ElastoPlasticRodMaterial::yieldStrength_

protected

◆ yieldType_

YieldType ElastoPlasticRodMaterial::yieldType_

protected

Public Types

Public Member Functions

Static Public Member Functions

Static Public Attributes

Protected Member Functions

Protected Attributes

Detailed Description

Member Enumeration Documentation

◆ YieldType

Constructor & Destructor Documentation

◆ ElastoPlasticRodMaterial()

◆ ~ElastoPlasticRodMaterial()

Member Function Documentation

◆ applyDeform()

◆ configure()

◆ declare()

◆ getConfig()

◆ getDissipatedEnergy()

◆ getHardeningPotential()

◆ getHardVals()

◆ getPotentialEnergy()

◆ getStress() [1/2]

◆ getStress() [2/2]

◆ getSuperEllipse_()

◆ getSuperEllipseGrad_()

◆ getTable()

◆ getYield_()

◆ getYieldGrad_()

◆ makeNew()

◆ rejectDeform()

Member Data Documentation

◆ argCount_

◆ currDeltaFlow_

◆ currHardParams_

◆ currPlastStrains_

◆ dofCount_

◆ elasticStrain_

◆ energyDiss_

◆ energyHardPot_

◆ hardParams_

◆ hardStress_

◆ ISO_HARD_PROP

◆ isoHard_

◆ KIN_HARD_PROP

◆ kinHard_

◆ materialH_

◆ maxIter_

◆ oldHardParams_

◆ oldPlastStrains_

◆ oldStresses_

◆ plastStrain_

◆ precision_

◆ TYPE_NAME

◆ YIELD_DERIV_PROP

◆ YIELD_EXPONENT_PROP

◆ YIELD_PROP

◆ YIELD_STRENGTH_PROP

◆ YIELD_TYPE_PROP

◆ yieldArgs_

◆ yieldCond_

◆ yieldDeriv_

◆ yieldExponent_

◆ yieldGrad_

◆ yieldStrength_

◆ yieldType_