chrono::fea::ChElementBrick_9 Class Reference

Description

Brick element with 9 nodes.

#include <ChElementBrick_9.h>

Inheritance diagram for chrono::fea::ChElementBrick_9:
Collaboration diagram for chrono::fea::ChElementBrick_9:

Public Types

enum  StrainFormulation { GreenLagrange, Hencky }
 Strain type calculation. More...
 
enum  PlasticityFormulation { J2, DruckerPrager, DruckerPrager_Cap }
 Plasticity formulation. More...
 

Public Member Functions

virtual int GetNnodes () override
 Get number of nodes of this element.
 
virtual int GetNdofs () override
 Get number of degrees of freedom of this element.
 
virtual int GetNodeNdofs (int n) override
 Get the number of coordinates from the n-th node used by this element.
 
virtual std::shared_ptr
< ChNodeFEAbase
GetNodeN (int n) override
 Access the n-th node of this element.
 
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 ChVector<> &dims)
 DP_Cap parameter. More...
 
const ChVectorGetDimensions () 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
< ChContinuumElastic
GetMaterial () const
 Get a handle to the continuum material used by this element.
 
void SetGravityOn (bool val)
 Enable/disable internal gravity calculation.
 
bool IsGravityOn () const
 Check if internal gravity calculation is enabled/disabled.
 
void SetAlphaDamp (double a)
 Set the structural damping.
 
void SetStrainFormulation (StrainFormulation model)
 Set the strain formulation.
 
StrainFormulation GetStrainFormulation () const
 Get the strain formulation.
 
void SetPlasticityFormulation (PlasticityFormulation model)
 Set the plasticity formulation.
 
PlasticityFormulation GetPlasticityFormulation () const
 Get 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 (ChMatrix<> &N, double x, double y, double z)
 Calculate shape functions and their derivatives. More...
 
void ShapeFunctionsDerivativeX (ChMatrix<> &Nx, double x, double y, double z)
 Calculate shape function derivative w.r.t. X.
 
void ShapeFunctionsDerivativeY (ChMatrix<> &Ny, double x, double y, double z)
 Calculate shape function derivative w.r.t. Y.
 
void ShapeFunctionsDerivativeZ (ChMatrix<> &Nz, double x, double y, double z)
 Calculate shape function derivative w.r.t. Z.
 
virtual int Get_field_ncoords () override
 Number of coordinates in the interpolated field: here the {x,y,z} displacement.
 
virtual int GetSubBlocks () override
 Tell the number of DOFs blocks: here 9, 1 for each node.
 
virtual unsigned int GetSubBlockOffset (int nblock) override
 Get the offset of the i-th sub-block of DOFs in global vector.
 
virtual unsigned int GetSubBlockSize (int nblock) override
 Get the size of the i-th sub-block of DOFs in global vector.
 
virtual int LoadableGet_ndof_x () override
 Get the number of DOFs affected by this element (position part).
 
virtual int LoadableGet_ndof_w () override
 Get the number of DOFs affected by this element (speed part).
 
virtual void LoadableGetStateBlock_x (int block_offset, ChState &mD) override
 Get all the DOFs packed in a single vector (position part).
 
virtual void LoadableGetStateBlock_w (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...
 
virtual ChMatrixNM< double, 6, 6 > GetE_eps ()
 
- Public Member Functions inherited from chrono::fea::ChElementGeneric
ChKblockGenericKstiffness ()
 Access the proxy to stiffness, for sparse solver.
 
virtual void EleIntLoadResidual_F (ChVectorDynamic<> &R, const double c) override
 (This is a default (a bit unoptimal) book keeping so that in children classes you can avoid implementing this EleIntLoadResidual_F function, unless you need faster code)
 
virtual void EleIntLoadResidual_Mv (ChVectorDynamic<> &R, const ChVectorDynamic<> &w, const double c) override
 (This is a default (VERY UNOPTIMAL) book keeping so that in children classes you can avoid implementing this EleIntLoadResidual_Mv function, unless you need faster code.)
 
virtual void InjectKRMmatrices (ChSystemDescriptor &mdescriptor) override
 Tell to a system descriptor that there are item(s) of type ChKblock in this object (for further passing it to a solver)
 
virtual void KRMmatricesLoad (double Kfactor, double Rfactor, double Mfactor) override
 Adds the current stiffness K and damping R and mass M matrices in encapsulated ChKblock item(s), if any. More...
 
virtual void VariablesFbLoadInternalForces (double factor=1.) override
 Adds the internal forces, expressed as nodal forces, into the encapsulated ChVariables, in the 'fb' part: qf+=forces*factor (This is a default (a bit unoptimal) book keeping so that in children classes you can avoid implementing this VariablesFbLoadInternalForces function, unless you need faster code)
 
virtual void VariablesFbIncrementMq () override
 Adds M*q (internal masses multiplied current 'qb') to Fb, ex. More...
 
- Public Member Functions inherited from chrono::fea::ChElementBase
virtual void ComputeNodalMass ()
 Compute element's nodal masses.
 
- 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 quadrature over u,v,w in [-1..+1] as box isoparametric coords. More...
 

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 MyMassBrick9
 
class MyGravityBrick9
 
class MyForceBrick9
 
class MyJacobianBrick9
 

Additional Inherited Members

- Protected Attributes inherited from chrono::fea::ChElementGeneric
ChKblockGeneric Kmatr
 

Member Enumeration Documentation

Plasticity formulation.

Enumerator
J2 

J2 plasticity (metals)

DruckerPrager 

Drucker-Prager plasticity (soil)

DruckerPrager_Cap 

Drucker-Prager-Cap plasticity (soil)

Strain type calculation.

Enumerator
GreenLagrange 

Green-Lagrange strain formulation.

Hencky 

Hencky strain.

Member Function Documentation

void chrono::fea::ChElementBrick_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.

virtual double chrono::fea::ChElementBrick_9::GetDensity ( )
overridevirtual

Return the material density.

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

Implements chrono::ChLoadableUVW.

void chrono::fea::ChElementBrick_9::SetDimensions ( const ChVector<> &  dims)

DP_Cap parameter.

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

void chrono::fea::ChElementBrick_9::ShapeFunctions ( ChMatrix<> &  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)