Description

Contact element of triangular type.

Used to 'tessellate' the surface of FEA meshes for collision purposes.

#include <ChContactSurfaceMesh.h>

Inheritance diagram for chrono::fea::ChContactTriangleXYZ:

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Collaboration diagram for chrono::fea::ChContactTriangleXYZ:

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Public Member Functions
	ChContactTriangleXYZ (const std::array< std::shared_ptr< ChNodeFEAxyz >, 3 > &nodes, ChContactSurface *container=nullptr)

void	SetNodes (const std::array< std::shared_ptr< ChNodeFEAxyz >, 3 > &nodes)
	Set the FEA nodes for which this is a proxy.

void	SetContactSurface (ChContactSurface *container)
	Set the contact surface container.

void	SetNodeOwnership (const ChVector3b &owns_node)
	Set node ownership.

void	SetEdgeOwnership (const ChVector3b &owns_edge)
	Set edge ownership.

std::shared_ptr< ChNodeFEAxyz >	GetNode (int i) const
	Acccess the specified FEA node for which this is a proxy.

ChContactSurface *	GetContactSurface () const
	Get the contact surface container.

bool	OwnsNode (int i) const
	Returns true if the specified node is owned by this triangle.

bool	OwnsEdge (int i) const
	Returns true if the specified edge is owned by this triangle.

virtual ChContactable::eChContactableType	GetContactableType () const override
	This must return the proper eChContactableType enum, for allowing a faster collision dispatcher in ChContactContainer classes (this enum will be used instead of slow dynamic_cast<> to infer the type of ChContactable, if possible)

virtual ChVariables *	GetVariables1 () override
	Access variables for node 1.

virtual ChVariables *	GetVariables2 () override
	Access variables for node 2.

virtual ChVariables *	GetVariables3 () override
	Access variables for node 3.

virtual bool	IsContactActive () override
	Tell if the object must be considered in collision detection.

virtual int	GetContactableNumCoordsPosLevel () override
	Get the number of DOFs affected by this object (position part).

virtual int	GetContactableNumCoordsVelLevel () override
	Get the number of DOFs affected by this object (speed part).

virtual void	ContactableGetStateBlockPosLevel (ChState &x) override
	Get all the DOFs packed in a single vector (position part).

virtual void	ContactableGetStateBlockVelLevel (ChStateDelta &w) override
	Get all the DOFs packed in a single vector (speed part).

virtual void	ContactableIncrementState (const ChState &x, const ChStateDelta &dw, ChState &x_new) override
	Increment the provided state of this object by the given state-delta increment. More...

virtual ChVector3d	GetContactPoint (const ChVector3d &loc_point, const ChState &state_x) override
	Express the local point in absolute frame, for the given state position.

virtual ChVector3d	GetContactPointSpeed (const ChVector3d &loc_point, const ChState &state_x, const ChStateDelta &state_w) override
	Get the absolute speed of a local point attached to the contactable. More...

virtual ChVector3d	GetContactPointSpeed (const ChVector3d &abs_point) override
	Get the absolute speed of point abs_point if attached to the surface. More...

virtual ChFrame	GetCollisionModelFrame () override
	Return the frame of the associated collision model relative to the contactable object.

virtual void	ContactForceLoadResidual_F (const ChVector3d &F, const ChVector3d &T, const ChVector3d &abs_point, ChVectorDynamic<> &R) override
	Apply the force & torque, expressed in absolute reference, applied in pos, to the coordinates of the variables. More...

virtual void	ContactComputeQ (const ChVector3d &F, const ChVector3d &T, const ChVector3d &point, const ChState &state_x, ChVectorDynamic<> &Q, int offset) override
	Compute a contiguous vector of generalized forces Q from a given force & torque at the given point. More...

virtual void	ComputeJacobianForContactPart (const ChVector3d &abs_point, ChMatrix33<> &contact_plane, type_constraint_tuple &jacobian_tuple_N, type_constraint_tuple &jacobian_tuple_U, type_constraint_tuple &jacobian_tuple_V, bool second) override
	Compute the jacobian(s) part(s) for this contactable item. More...

virtual double	GetContactableMass () override
	Return mass of contactable object.

virtual ChPhysicsItem *	GetPhysicsItem () override
	This is only for backward compatibility.

virtual unsigned int	GetLoadableNumCoordsPosLevel () override
	Gets the number of DOFs affected by this element (position part).

virtual unsigned int	GetLoadableNumCoordsVelLevel () override
	Gets the number of DOFs affected by this element (velocity part).

virtual void	LoadableGetStateBlockPosLevel (int block_offset, ChState &mD) override
	Gets all the DOFs packed in a single vector (position part).

virtual void	LoadableGetStateBlockVelLevel (int block_offset, ChStateDelta &mD) override
	Gets all the DOFs packed in a single vector (velocity 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 unsigned int	GetNumFieldCoords () override
	Number of coordinates in the interpolated field, ex=3 for a tetrahedron finite element or a cable, = 1 for a thermal problem, etc.

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 void	LoadableGetVariables (std::vector< ChVariables * > &mvars) override
	Get the pointers to the contained ChVariables, appending to the mvars vector.

virtual bool	IsSubBlockActive (unsigned int nblock) const override
	Check if the specified sub-block of DOFs is active.

virtual void	ComputeNF (const double U, const double V, 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 coordinates of the surface, each ranging in 0..+1 (as IsTriangleIntegrationNeeded() is true) 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 ChVector3d	ComputeNormal (const double U, const double V) override
	Gets the normal to the surface at the parametric coordinate U,V. More...

virtual bool	IsTriangleIntegrationNeeded () override
	If true, use quadrature over u,v in [0..1] range as triangle volumetric coords.

void	ComputeUVfromP (const ChVector3d P, double &u, double &v)
	Compute u,v of contact point respect to triangle. More...

Member Function Documentation

◆ ComputeJacobianForContactPart()

void chrono::fea::ChContactTriangleXYZ::ComputeJacobianForContactPart	(	const ChVector3d &	abs_point,
		ChMatrix33<> &	contact_plane,
		type_constraint_tuple &	jacobian_tuple_N,
		type_constraint_tuple &	jacobian_tuple_U,
		type_constraint_tuple &	jacobian_tuple_V,
		bool	second
	)

overridevirtual

Compute the jacobian(s) part(s) for this contactable item.

For example, if the contactable is a ChBody, this should update the corresponding 1x6 jacobian.

◆ ComputeNF()

void chrono::fea::ChContactTriangleXYZ::ComputeNF	(	const double	U,
		const double	V,
		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 coordinates of the surface, each ranging in 0..+1 (as IsTriangleIntegrationNeeded() is true) 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

U	parametric coordinate in surface
V	parametric coordinate in surface
Qi	Return result of Q = N'*F here
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::ChLoadableUV.

◆ ComputeNormal()

ChVector3d chrono::fea::ChContactTriangleXYZ::ComputeNormal	(	const double	U,
		const double	V
	)

overridevirtual

Gets the normal to the surface at the parametric coordinate U,V.

Each coordinate ranging in -1..+1.

Implements chrono::ChLoadableUV.

◆ ComputeUVfromP()

void chrono::fea::ChContactTriangleXYZ::ComputeUVfromP	(	const ChVector3d	P,
		double &	u,
		double &	v
	)

Compute u,v of contact point respect to triangle.

u is in the node1->node2 direction.
v is in the node1->node3 direction.

◆ ContactableIncrementState()

void chrono::fea::ChContactTriangleXYZ::ContactableIncrementState	(	const ChState &	x,
		const ChStateDelta &	dw,
		ChState &	x_new
	)

overridevirtual

Increment the provided state of this object by the given state-delta increment.

Compute: x_new = x + dw.

Implements chrono::ChContactable.

◆ ContactComputeQ()

void chrono::fea::ChContactTriangleXYZ::ContactComputeQ	(	const ChVector3d &	F,
		const ChVector3d &	T,
		const ChVector3d &	point,
		const ChState &	state_x,
		ChVectorDynamic<> &	Q,
		int	offset
	)

overridevirtual

Compute a contiguous vector of generalized forces Q from a given force & torque at the given point.

Used for computing stiffness matrix (square force jacobian) by backward differentiation. The force and its application point are specified in the global frame. Each object must set the entries in Q corresponding to its variables, starting at the specified offset. If needed, the object states must be extracted from the provided state position.

Implements chrono::ChContactable.

◆ ContactForceLoadResidual_F()

void chrono::fea::ChContactTriangleXYZ::ContactForceLoadResidual_F	(	const ChVector3d &	F,
		const ChVector3d &	T,
		const ChVector3d &	abs_point,
		ChVectorDynamic<> &	R
	)

overridevirtual

Apply the force & torque, expressed in absolute reference, applied in pos, to the coordinates of the variables.

Force for example could come from a penalty model.

Implements chrono::ChContactable.

◆ GetContactPointSpeed() [1/2]

ChVector3d chrono::fea::ChContactTriangleXYZ::GetContactPointSpeed ( const ChVector3d & abs_point )

overridevirtual

Get the absolute speed of point abs_point if attached to the surface.

Easy in this case because there are no rotations..

Implements chrono::ChContactable.

◆ GetContactPointSpeed() [2/2]

ChVector3d chrono::fea::ChContactTriangleXYZ::GetContactPointSpeed	(	const ChVector3d &	loc_point,
		const ChState &	state_x,
		const ChStateDelta &	state_w
	)

overridevirtual

Get the absolute speed of a local point attached to the contactable.

The given point is assumed to be expressed in the local frame of this object. This function must use the provided states.

Implements chrono::ChContactable.

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

/builds/uwsbel/chrono/src/chrono/fea/ChContactSurfaceMesh.h
/builds/uwsbel/chrono/src/chrono/fea/ChContactSurfaceMesh.cpp

Description

Public Member Functions

Member Function Documentation

◆ ComputeJacobianForContactPart()

◆ ComputeNF()

◆ ComputeNormal()

◆ ComputeUVfromP()

◆ ContactableIncrementState()

◆ ContactComputeQ()

◆ ContactForceLoadResidual_F()

◆ GetContactPointSpeed() [1/2]

◆ GetContactPointSpeed() [2/2]