Description
Tetrahedron FEM element with 4 nodes for scalar fields (for Poisson-like problems).
This is a classical element with linear displacement. EXPERIMENTAL
#include <ChElementTetraCorot_4.h>
Public Types | |
using | ShapeVector = ChMatrixNM< double, 1, 4 > |
Public Member Functions | |
virtual int | GetNnodes () override |
Get the number of nodes used by this element. | |
virtual int | GetNdofs () override |
Get the number of coordinates in the field used by the referenced nodes. More... | |
virtual int | GetNodeNdofs (int n) override |
Get the number of coordinates from the specified node that are used by this element. More... | |
double | GetVolume () |
virtual std::shared_ptr< ChNodeFEAbase > | GetNodeN (int n) override |
Access the nth node. | |
virtual void | SetNodes (std::shared_ptr< ChNodeFEAxyzP > nodeA, std::shared_ptr< ChNodeFEAxyzP > nodeB, std::shared_ptr< ChNodeFEAxyzP > nodeC, std::shared_ptr< ChNodeFEAxyzP > nodeD) |
virtual void | Update () override |
Update element at each time step. | |
virtual void | ShapeFunctions (ShapeVector &N, double z0, double z1, double z2) |
Fills the N shape function matrix with the values of shape functions at zi parametric coordinates, where z0=1 at 1st vertex, z1=1 at second, z2 = 1 at third (volumetric shape functions). More... | |
virtual void | GetStateBlock (ChVectorDynamic<> &mD) override |
Fills the D vector with the current field values at the nodes of the element, with proper ordering. More... | |
double | ComputeVolume () |
virtual void | ComputeStiffnessMatrix () |
Computes the local STIFFNESS MATRIX of the element: K = Volume * [B]' * [D] * [B]. | |
virtual void | UpdateRotation () override |
Given the actual position of the nodes, recompute the cumulative rotation matrix A. | |
virtual void | ComputeKRMmatricesGlobal (ChMatrixRef H, double Kfactor, double Rfactor=0, double Mfactor=0) override |
Sets H as the global stiffness matrix K, scaled by Kfactor. More... | |
virtual void | ComputeInternalForces (ChVectorDynamic<> &Fi) override |
Computes the internal 'pseudo-forces' and set values in the Fi vector. | |
void | SetMaterial (std::shared_ptr< ChContinuumPoisson3D > my_material) |
Set the material of the element. | |
std::shared_ptr< ChContinuumPoisson3D > | GetMaterial () |
const ChMatrixDynamic & | GetMatrB () const |
Get the partial derivatives matrix MatrB and the StiffnessMatrix. | |
const ChMatrixDynamic & | GetStiffnessMatrix () const |
ChVectorN< double, 3 > | GetPgradient () |
Returns the gradient of P (note that the tetrahedron 4 nodes is a linear element, thus the gradient is constant in the entire volume). More... | |
virtual int | LoadableGet_ndof_x () override |
Gets the number of DOFs affected by this element (position part) | |
virtual int | LoadableGet_ndof_w () override |
Gets the number of DOFs affected by this element (speed part) | |
virtual void | LoadableGetStateBlock_x (int block_offset, ChState &mD) override |
Gets all the DOFs packed in a single vector (position part) | |
virtual void | LoadableGetStateBlock_w (int block_offset, ChStateDelta &mD) override |
Gets 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 int | Get_field_ncoords () override |
Number of coordinates in the interpolated field: here the {t} temperature. | |
virtual int | GetSubBlocks () override |
Get the number of DOFs sub-blocks. | |
virtual unsigned int | GetSubBlockOffset (int nblock) override |
Get the offset of the specified sub-block of DOFs in global vector. | |
virtual unsigned int | GetSubBlockSize (int nblock) override |
Get the size of the specified sub-block of DOFs in global vector. | |
virtual bool | IsSubBlockActive (int nblock) const override |
Check if the specified sub-block of DOFs is active. | |
virtual void | LoadableGetVariables (std::vector< ChVariables * > &mvars) override |
Get the pointers to the contained ChVariables, 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 coordinates of the volume, each ranging in 0..+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. More... | |
virtual double | GetDensity () override |
Return 0 if not supportable by ChLoaderVolumeGravity. | |
virtual bool | IsTetrahedronIntegrationNeeded () override |
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. | |
Public Member Functions inherited from chrono::fea::ChElementGeneric | |
ChKblockGeneric & | Kstiffness () |
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 | EleIntLoadResidual_F_gravity (ChVectorDynamic<> &R, const ChVector<> &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 | ComputeGravityForces (ChVectorDynamic<> &Fg, const ChVector<> &G_acc) override |
Compute the gravitational forces. More... | |
virtual void | ComputeMmatrixGlobal (ChMatrixRef M) override |
Calculate the mass matrix, expressed in global reference. More... | |
virtual void | InjectKRMmatrices (ChSystemDescriptor &descriptor) 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 |
Add 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 |
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 int | GetNdofs_active () |
Get the actual number of active degrees of freedom. More... | |
virtual int | GetNodeNdofs_active (int n) |
Get the actual number of active coordinates from the specified node that are used by this element. More... | |
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::fea::ChElementCorotational | |
ChMatrix33 & | Rotation () |
Access the cumulative rotation matrix of the element. More... | |
Public Member Functions inherited from chrono::ChLoadableUVW | |
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. | |
Additional Inherited Members | |
Protected Attributes inherited from chrono::fea::ChElementGeneric | |
ChKblockGeneric | Kmatr |
Protected Attributes inherited from chrono::fea::ChElementCorotational | |
ChMatrix33 | A |
Member Function Documentation
◆ ComputeKRMmatricesGlobal()
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overridevirtual |
Sets H as the global stiffness matrix K, scaled by Kfactor.
Optionally, also superimposes global damping matrix R, scaled by Rfactor, and global mass matrix M multiplied by Mfactor.
Implements chrono::fea::ChElementBase.
◆ ComputeNF()
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overridevirtual |
Evaluate N'*F , where N is some type of shape function evaluated at U,V,W coordinates of the volume, each ranging in 0..+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
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U parametric coordinate in volume V parametric coordinate in volume W parametric coordinate in volume Qi Return result of N'*F here, maybe with offset block_offset detJ Return det[J] here F Input F vector, size is = n.field coords. state_x if != 0, update state (pos. part) to this, then evaluate Q state_w if != 0, update state (speed part) to this, then evaluate Q
Implements chrono::ChLoadableUVW.
◆ GetNdofs()
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inlineoverridevirtual |
Get the number of coordinates in the field used by the referenced nodes.
This is for example the size (number of rows/columns) of the local stiffness matrix.
Implements chrono::fea::ChElementBase.
◆ GetNodeNdofs()
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inlineoverridevirtual |
Get the number of coordinates from the specified node that are used by this element.
Note that this may be different from the value returned by GetNodeN(n)->GetNdofW().
Implements chrono::fea::ChElementBase.
◆ GetPgradient()
ChVectorN< double, 3 > chrono::fea::ChElementTetraCorot_4_P::GetPgradient | ( | ) |
Returns the gradient of P (note that the tetrahedron 4 nodes is a linear element, thus the gradient is constant in the entire volume).
It is in the original undeformed unrotated reference.
◆ GetStateBlock()
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overridevirtual |
Fills the D vector with the current field values at the nodes of the element, with proper ordering.
If the D vector has not the size of this->GetNdofs(), it will be resized. For corotational elements, field is assumed in local reference!
Implements chrono::fea::ChElementBase.
◆ ShapeFunctions()
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virtual |
Fills the N shape function matrix with the values of shape functions at zi parametric coordinates, where z0=1 at 1st vertex, z1=1 at second, z2 = 1 at third (volumetric shape functions).
The 4th is computed form the first 3. All ranging in [0...1]. NOTE! actually N should be a 3row, 12 column sparse matrix, as N = [n1*eye(3) n2*eye(3) n3*eye(3) n4*eye(3)]; , but to avoid wasting zero and repeated elements, here it stores only the n1 n2 n3 n4 values in a 1 row, 4 columns matrix!
The documentation for this class was generated from the following files:
- /builds/uwsbel/chrono/src/chrono/fea/ChElementTetraCorot_4.h
- /builds/uwsbel/chrono/src/chrono/fea/ChElementTetraCorot_4.cpp