Description

Class for properties of a non-linear thermal material in finite element problems.

This a quite pupular type of non-linearity, where the thermal properties (c specific heat, k thermal conductivity) are scalar functions of temperature T, i.e. c=c(T), k=k(T),
assuming isotropic thermal conductivity matrix [k](T)=[I]*k(T), as in: (c(T)*rho) dT/dt - div ([k](T) * grad T) = q_source

#include <ChMaterial3DThermalNonlinear.h>

Inheritance diagram for chrono::fea::ChMaterial3DThermalNonlinear:

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Collaboration diagram for chrono::fea::ChMaterial3DThermalNonlinear:

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Public Member Functions
void	SetThermalConductivity (std::shared_ptr< ChFunction > mk)
	Sets the k conductivity constant of the material as a function of temperature T, k=k(T) where k has the units of watts per meter kelvin [ W/(m K) ]. More...

void	SetThermalConductivity (double mk)
	Shortcut: sets the k conductivity constant of the material as a constant ChFunction. More...

std::shared_ptr< ChFunction >	GetThermalConductivity () const
	Gets the k conductivity of the material as a function of temperature T, k=k(T) expressed in watts per meter kelvin (W/(m K)).

void	SetSpecificHeatCapacity (std::shared_ptr< ChFunction > mc)
	Sets the c mass-specific heat capacity of the material, as a function of temperature T, c=c(T) where c has the units of Joule per kg Kelvin [ J / (kg K) ].

void	SetSpecificHeatCapacity (double mc)
	Shortcut: sets the c mass-specific heat capacity of the material, as a function of temperature T, c=c(T) where c has the units of Joule per kg Kelvin [ J / (kg K) ].

std::shared_ptr< ChFunction >	GetSpecificHeatCapacity () const
	Gets the c mass-specific heat capacity of the material, as a function of temperature T, c=c(T) where c has the units of Joule per kg Kelvin [ J / (kg K) ].

ChMatrixDynamic &	GetConductivityMatrix (double T)
	Get the k conductivity matrix for a given temperature T. It is also the constitutive matrix of the Poisson problem.

virtual double	Get_DtMultiplier () override
	override base: (the dT/dt term has multiplier rho*c with rho=density, c=heat capacity)

virtual void	ComputeHeatFlux (ChVector3d &q_flux, const ChVector3d grad_T, const double T, ChFieldData data_per_point, ChElementData data_per_element) override
	Compute heat flux vector q_flux from a temperature gradient grad_T q_flux = f(grad_T) Because of nonlinear model with temperature-dependant conductivity k=k(T) this is q_flux = -[k](T) * grad_T with conductivity matrix [k](T) = [I] * k(T) . More...

virtual void	ComputeTangentModulus (ChMatrix33d &tangent_matrix, const ChVector3d grad_T, const double T, ChFieldData data_per_point, ChElementData data_per_element) override
	Computes the tangent conductivity [C] in the linearization of q_flux = f(grad_T) about temperature: δq_flux = [C] δgrad_T Because of nonlinear model, this is [C] = [k](T) = [I] * k(T) More...

virtual void	ComputeDtMultiplier (double &Dt_multiplier, const double T, ChFieldData data_per_point, ChElementData data_per_element) override
	Computes the Z multiplier in ZdT/dt + div q_flux = q_source: Because of linear model, this is Z=(m_density c_mass_specific_heat_capacity) More...

Public Member Functions inherited from chrono::fea::ChMaterialPoisson
ChMatrixDynamic &	ConstitutiveMatrix ()
	The constitutive matrix [C] to compute the bilinear form in the weak formulation. More...

Public Member Functions inherited from chrono::fea::ChMaterial3DDensity
	ChMaterial3DDensity (double density=1000)

virtual void	SetDensity (double density)
	Set the density of the material, in kg/m^2.

virtual double	GetDensity () const
	Get the density of the material, in kg/m^2.

Public Member Functions inherited from chrono::fea::ChMaterial
virtual std::unique_ptr< ChFieldData >	CreateMaterialPointData () const
	Implement this if the material needs custom data per material point, returning a std::make_unique<ChFieldDataCustom>() where ChFieldDataCustom is your custom class with aditional states/properties per-point.

Additional Inherited Members
Protected Attributes inherited from chrono::fea::ChMaterialPoisson
ChMatrixDynamic	constitutiveMatrix

Protected Attributes inherited from chrono::fea::ChMaterial3DDensity
double	m_density

Member Function Documentation

◆ ComputeDtMultiplier()

virtual void chrono::fea::ChMaterial3DThermalNonlinear::ComputeDtMultiplier	(	double &	Dt_multiplier,
		const double	T,
		ChFieldData *	data_per_point,
		ChElementData *	data_per_element
	)

inlineoverridevirtual

Computes the Z multiplier in Z*dT/dt + div q_flux = q_source: Because of linear model, this is Z=(m_density * c_mass_specific_heat_capacity)

Parameters

Dt_multiplier	the Z term in Z*dT/dt + div(q_flux) = q_source
T	current temperature (not used here)
data_per_point	pointer to auxiliary data (ex states), if any, per quadrature point (not used here)
data_per_element	pointer to auxiliary data (ex states), if any, per element (not used here)

Implements chrono::fea::ChMaterial3DThermal.

◆ ComputeHeatFlux()

virtual void chrono::fea::ChMaterial3DThermalNonlinear::ComputeHeatFlux	(	ChVector3d &	q_flux,
		const ChVector3d	grad_T,
		const double	T,
		ChFieldData *	data_per_point,
		ChElementData *	data_per_element
	)

inlineoverridevirtual

Compute heat flux vector q_flux from a temperature gradient grad_T q_flux = f(grad_T) Because of nonlinear model with temperature-dependant conductivity k=k(T) this is q_flux = -[k](T) * grad_T with conductivity matrix [k](T) = [I] * k(T) .

Parameters

q_flux	output stress, PK2
grad_T	current temperature gradient
T	current temperature (not used here)
data_per_point	pointer to auxiliary data (ex states), if any, per quadrature point (not used here)
data_per_element	pointer to auxiliary data (ex states), if any, per element (not used here)

Implements chrono::fea::ChMaterial3DThermal.

◆ ComputeTangentModulus()

virtual void chrono::fea::ChMaterial3DThermalNonlinear::ComputeTangentModulus	(	ChMatrix33d &	tangent_matrix,
		const ChVector3d	grad_T,
		const double	T,
		ChFieldData *	data_per_point,
		ChElementData *	data_per_element
	)

inlineoverridevirtual

Computes the tangent conductivity [C] in the linearization of q_flux = f(grad_T) about temperature: δq_flux = [C] δgrad_T Because of nonlinear model, this is [C] = [k](T) = [I] * k(T)

Parameters

tangent_matrix	output [C] tangent as δq_flux = [C] δgrad_T
grad_T	current temperature gradient (not used here)
T	current temperature (not used here)
data_per_point	pointer to auxiliary data (ex states), if any, per quadrature point (not used here)
data_per_element	pointer to auxiliary data (ex states), if any, per element (not used here)

Implements chrono::fea::ChMaterial3DThermal.

◆ SetThermalConductivity() [1/2]

void chrono::fea::ChMaterial3DThermalNonlinear::SetThermalConductivity ( double mk )

inline

Shortcut: sets the k conductivity constant of the material as a constant ChFunction.

where k has the units of watts per meter kelvin [ W/(m K) ].

◆ SetThermalConductivity() [2/2]

void chrono::fea::ChMaterial3DThermalNonlinear::SetThermalConductivity ( std::shared_ptr< ChFunction > mk )

inline

Sets the k conductivity constant of the material as a function of temperature T, k=k(T) where k has the units of watts per meter kelvin [ W/(m K) ].

Ex. (approx.): water = 0.6, aluminium = 200, steel = 50, plastics=0.9-0.2 Note: conductivity matrix [k] is assumed isotropic (diagonal matrix ie. [k]=[I]*k(T) )

The documentation for this class was generated from the following file:

/builds/uwsbel/chrono/src/chrono/fea/ChMaterial3DThermalNonlinear.h

Description

Public Member Functions

Additional Inherited Members

Member Function Documentation

◆ ComputeDtMultiplier()

◆ ComputeHeatFlux()

◆ ComputeTangentModulus()

◆ SetThermalConductivity() [1/2]

◆ SetThermalConductivity() [2/2]