Description

Hexahedronal solid element with 8 nodes and a central curvature node.

While technically not an ANCF element, the name is justified because the implementation can use the same ANCF machinery.

#include <ChElementHexaANCF_3813_9.h>

Inheritance diagram for chrono::fea::ChElementHexaANCF_3813_9:
Collaboration diagram for chrono::fea::ChElementHexaANCF_3813_9:

Public Types

enum  StrainFormulation { StrainFormulation::GreenLagrange, StrainFormulation::Hencky }
 Strain type calculation. More...
 
enum  PlasticityFormulation { PlasticityFormulation::J2, PlasticityFormulation::DruckerPrager, PlasticityFormulation::DruckerPrager_Cap }
 Plasticity formulation. More...
 
using ShapeVector = ChMatrixNM< double, 1, 11 >
 

Public Member Functions

virtual unsigned int GetNumNodes () override
 Get number of nodes of this element.
 
virtual unsigned int GetNumCoordsPosLevel () override
 Get the number of coordinates in the field used by the referenced nodes.
 
virtual unsigned int GetNumCoordsPosLevelActive () override
 Get the number of active coordinates in the field used by the referenced nodes.
 
virtual unsigned int GetNodeNumCoordsPosLevel (unsigned int n) override
 Get the number of coordinates from the n-th node used by this element.
 
virtual unsigned int GetNodeNumCoordsPosLevelActive (unsigned int n) override
 Get the number of active coordinates from the n-th node used by this element.
 
virtual std::shared_ptr< ChNodeFEAbaseGetNode (unsigned int n) override
 Access the n-th node of this element.
 
virtual std::shared_ptr< ChNodeFEAxyzGetHexahedronNode (unsigned int n) override
 Return the specified hexahedron node (0 <= n <= 7).
 
void SetNodes (std::shared_ptr< ChNodeFEAxyz > node1, std::shared_ptr< ChNodeFEAxyz > node2, std::shared_ptr< ChNodeFEAxyz > node3, std::shared_ptr< ChNodeFEAxyz > node4, std::shared_ptr< ChNodeFEAxyz > node5, std::shared_ptr< ChNodeFEAxyz > node6, std::shared_ptr< ChNodeFEAxyz > node7, std::shared_ptr< ChNodeFEAxyz > node8, std::shared_ptr< ChNodeFEAcurv > nodeC)
 Specify the nodes of this element.
 
std::shared_ptr< ChNodeFEAxyzGetNode1 () const
 Get access to individual nodes of this element.
 
std::shared_ptr< ChNodeFEAxyzGetNode2 () const
 
std::shared_ptr< ChNodeFEAxyzGetNode3 () const
 
std::shared_ptr< ChNodeFEAxyzGetNode4 () const
 
std::shared_ptr< ChNodeFEAxyzGetNode5 () const
 
std::shared_ptr< ChNodeFEAxyzGetNode6 () const
 
std::shared_ptr< ChNodeFEAxyzGetNode7 () const
 
std::shared_ptr< ChNodeFEAxyzGetNode8 () const
 
std::shared_ptr< ChNodeFEAcurvGetCentralNode () const
 
void SetDimensions (const ChVector3d &dims)
 DP_Cap parameter. More...
 
const ChVector3dGetDimensions () const
 Get the element dimensions (x, y, z directions).
 
void SetMaterial (std::shared_ptr< ChContinuumElastic > material)
 Set the continuum material for this element.
 
std::shared_ptr< ChContinuumElasticGetMaterial () const
 Get a handle to the continuum material used by this element.
 
void SetAlphaDamp (double a)
 Set the structural damping.
 
void SetStrainFormulation (StrainFormulation model)
 Set the strain formulation.
 
void SetPlasticityFormulation (PlasticityFormulation model)
 Set the plasticity formulation.
 
void SetDPIterationNo (int ItNo)
 Set the DP iteration number.
 
void SetDPVector1 (ChMatrixDynamic< double > vec)
 Set the hardening parameter look-up table.
 
void SetDPVector2 (ChMatrixDynamic< double > vec)
 
void SetDPVectorSize (int a)
 
void SetDPCapBeta (double a)
 Set DP_Cap parameter.
 
int GetDPIterationNo () const
 Get the DP iteration number.
 
void SetDPYieldTol (double yieldf_tol)
 Set the DP yield function tolerance.
 
double GetDPYieldTol () const
 Get the DP yield function tolerance.
 
void SetPlasticity (bool val)
 Set plasticity.
 
void SetDruckerPrager (bool val)
 Set Drucker-Prager plasticity.
 
void SetYieldStress (double a)
 Set yield stress for yield function.
 
void SetHardeningSlope (double a)
 Set linear isotropic modulus.
 
void SetFriction (double friction)
 Set internal friction angle.
 
void SetDilatancy (double dilatancy)
 Set dilatancy angle.
 
void SetDPType (int a)
 Set Drucker-Prager hardening type.
 
void SetCCPInitial (ChMatrixNM< double, 9, 8 > mat)
 Set initial strain tensor per integration point of the 9-node element.
 
void ShapeFunctions (ShapeVector &N, double x, double y, double z)
 Calculate shape functions and their derivatives. More...
 
void ShapeFunctionsDerivativeX (ShapeVector &Nx, double x, double y, double z)
 Calculate shape function derivative w.r.t. X.
 
void ShapeFunctionsDerivativeY (ShapeVector &Ny, double x, double y, double z)
 Calculate shape function derivative w.r.t. Y.
 
void ShapeFunctionsDerivativeZ (ShapeVector &Nz, double x, double y, double z)
 Calculate shape function derivative w.r.t. Z.
 
virtual unsigned int GetNumFieldCoords () override
 Number of coordinates in the interpolated field: here the {x,y,z} displacement.
 
virtual unsigned int GetNumSubBlocks () override
 Get the number of DOFs sub-blocks.
 
virtual unsigned int GetSubBlockOffset (unsigned int nblock) override
 Get the offset of the specified sub-block of DOFs in global vector.
 
virtual unsigned int GetSubBlockSize (unsigned int nblock) override
 Get the size of the specified sub-block of DOFs in global vector.
 
virtual bool IsSubBlockActive (unsigned int nblock) const override
 Check if the specified sub-block of DOFs is active.
 
virtual unsigned int GetLoadableNumCoordsPosLevel () override
 Get the number of DOFs affected by this element (position part).
 
virtual unsigned int GetLoadableNumCoordsVelLevel () override
 Get the number of DOFs affected by this element (speed part).
 
virtual void LoadableGetStateBlockPosLevel (int block_offset, ChState &mD) override
 Get all the DOFs packed in a single vector (position part).
 
virtual void LoadableGetStateBlockVelLevel (int block_offset, ChStateDelta &mD) override
 Get all the DOFs packed in a single vector (speed part).
 
virtual void LoadableStateIncrement (const unsigned int off_x, ChState &x_new, const ChState &x, const unsigned int off_v, const ChStateDelta &Dv) override
 Increment all DOFs using a delta.
 
virtual void LoadableGetVariables (std::vector< ChVariables * > &mvars) override
 Get the pointers to the contained ChLcpVariables, appending to the mvars vector.
 
virtual void ComputeNF (const double U, const double V, const double W, ChVectorDynamic<> &Qi, double &detJ, const ChVectorDynamic<> &F, ChVectorDynamic<> *state_x, ChVectorDynamic<> *state_w) override
 Evaluate N'*F, where N is some type of shape function evaluated at (U,V,W). More...
 
virtual double GetDensity () override
 Return the material density. More...
 
- Public Member Functions inherited from chrono::fea::ChElementGeneric
ChKRMBlockKstiffness ()
 Access the proxy to stiffness, for sparse solver.
 
virtual void EleIntLoadResidual_F (ChVectorDynamic<> &R, const double c) override
 Add the internal forces (pasted at global nodes offsets) into a global vector R, multiplied by a scaling factor c, as R += forces * c This default implementation is SLIGHTLY INEFFICIENT.
 
virtual void EleIntLoadResidual_Mv (ChVectorDynamic<> &R, const ChVectorDynamic<> &w, const double c) override
 Add the product of element mass M by a vector w (pasted at global nodes offsets) into a global vector R, multiplied by a scaling factor c, as R += M * w * c This default implementation is VERY INEFFICIENT.
 
virtual void EleIntLoadLumpedMass_Md (ChVectorDynamic<> &Md, double &error, const double c) override
 Adds the lumped mass to a Md vector, representing a mass diagonal matrix. More...
 
virtual void EleIntLoadResidual_F_gravity (ChVectorDynamic<> &R, const ChVector3d &G_acc, const double c) override
 Add the contribution of gravity loads, multiplied by a scaling factor c, as: R += M * g * c This default implementation is VERY INEFFICIENT. More...
 
virtual void InjectKRMMatrices (ChSystemDescriptor &descriptor) override
 Register with the given system descriptor any ChKRMBlock objects associated with this item.
 
virtual void LoadKRMMatrices (double Kfactor, double Rfactor, double Mfactor) override
 Compute and load current stiffnes (K), damping (R), and mass (M) matrices in encapsulated ChKRMBlock objects. More...
 
virtual void VariablesFbLoadInternalForces (double factor=1.) override
 Add the internal forces, expressed as nodal forces, into the encapsulated ChVariables.
 
virtual void VariablesFbIncrementMq () override
 Add M*q (internal masses multiplied current 'qb').
 
- Public Member Functions inherited from chrono::fea::ChElementBase
virtual void ComputeNodalMass ()
 Compute element's nodal masses.
 
virtual void EleDoIntegration ()
 This is optionally implemented if there is some internal state that requires integration.
 
- Public Member Functions inherited from chrono::ChLoadableUVW
virtual bool IsTetrahedronIntegrationNeeded ()
 If true, use quadrature over u,v,w in [0..1] range as tetrahedron volumetric coords (with z=1-u-v-w) otherwise use default quadrature over u,v,w in [-1..+1] as box isoparametric coords.
 
virtual bool IsTrianglePrismIntegrationNeeded ()
 If true, use quadrature over u,v in [0..1] range as triangle natural coords (with z=1-u-v), and use linear quadrature over w in [-1..+1], otherwise use default quadrature over u,v,w in [-1..+1] as box isoparametric coords.
 

Public Attributes

int m_DP_iterationNo
 Maximum number of iteration for DP return mapping.
 
double m_DP_yield
 Tolerance for yield function value (Drucker-Prager)
 
double m_DPCapBeta
 

Friends

class Brick9_Mass
 
class Brick9_Gravity
 
class Brick9_Force
 
class Brick9_Jacobian
 

Additional Inherited Members

- Protected Attributes inherited from chrono::fea::ChElementANCF
int m_element_dof
 actual number of degrees of freedom for the element
 
bool m_full_dof
 true if all node variables are active (not fixed)
 
ChArray< int > m_mapping_dof
 indices of active DOFs (set only is some are fixed)
 
- Protected Attributes inherited from chrono::fea::ChElementGeneric
ChKRMBlock Kmatr
 

Member Enumeration Documentation

◆ PlasticityFormulation

Plasticity formulation.

Enumerator
J2 

J2 plasticity (metals)

DruckerPrager 

Drucker-Prager plasticity (soil)

DruckerPrager_Cap 

Drucker-Prager-Cap plasticity (soil)

◆ StrainFormulation

Strain type calculation.

Enumerator
GreenLagrange 

Green-Lagrange strain formulation.

Hencky 

Hencky strain.

Member Function Documentation

◆ ComputeNF()

void chrono::fea::ChElementHexaANCF_3813_9::ComputeNF ( const double  U,
const double  V,
const double  W,
ChVectorDynamic<> &  Qi,
double &  detJ,
const ChVectorDynamic<> &  F,
ChVectorDynamic<> *  state_x,
ChVectorDynamic<> *  state_w 
)
overridevirtual

Evaluate N'*F, where N is some type of shape function evaluated at (U,V,W).

Here, U,V,W are coordinates of the volume, each ranging in -1..+1 F is a load, N'*F is the resulting generalized load Returns also det[J] with J=[dx/du,..], that might be useful in gauss quadrature.

Parameters
Uparametric coordinate in volume
Vparametric coordinate in volume
Wparametric coordinate in volume
QiReturn result of N'*F here, maybe with offset block_offset
detJReturn det[J] here
FInput F vector, size is = n.field coords.
state_xif != 0, update state (pos. part) to this, then evaluate Q
state_wif != 0, update state (speed part) to this, then evaluate Q

Implements chrono::ChLoadableUVW.

◆ GetDensity()

virtual double chrono::fea::ChElementHexaANCF_3813_9::GetDensity ( )
inlineoverridevirtual

Return the material density.

This is needed so that it can be accessed by ChLoaderVolumeGravity.

Implements chrono::ChLoadableUVW.

◆ SetDimensions()

void chrono::fea::ChElementHexaANCF_3813_9::SetDimensions ( const ChVector3d dims)
inline

DP_Cap parameter.

Set element dimensions (x, y, z directions).

◆ ShapeFunctions()

void chrono::fea::ChElementHexaANCF_3813_9::ShapeFunctions ( ShapeVector &  N,
double  x,
double  y,
double  z 
)

Calculate shape functions and their derivatives.

N = [N1, N2, N3, N4, ...] (1x11 row vector) S = [N1*eye(3), N2*eye(3), N3*eye(3) ,N4*eye(3), ...] (3x11 matrix)


The documentation for this class was generated from the following files:
  • /builds/uwsbel/chrono/src/chrono/fea/ChElementHexaANCF_3813_9.h
  • /builds/uwsbel/chrono/src/chrono/fea/ChElementHexaANCF_3813_9.cpp