chrono::vehicle::GranularTerrain Class Reference


Granular terrain model.

This class implements a rectangular patch of granular terrain with spherical particles. Boundary conditions (model of a container bin) are imposed through a custom collision detection object.

#include <GranularTerrain.h>

Inheritance diagram for chrono::vehicle::GranularTerrain:
Collaboration diagram for chrono::vehicle::GranularTerrain:

Public Member Functions

 GranularTerrain (ChSystem *system)
 Construct a default GranularTerrain. More...
void SetContactMaterial (std::shared_ptr< ChContactMaterial > material)
 Set contact material (must be consistent with the containing system).
std::shared_ptr< ChContactMaterialGetContactMaterial () const
 Get the current contact material.
void SetCollisionEnvelope (double envelope)
 Set outward collision envelope. More...
void SetMinNumParticles (unsigned int min_num_particles)
 Set the minimum number of particles to be generated (default: 0).
void EnableVerbose (bool val)
 Enable/disable verbose output (default: false).
void EnableRoughSurface (int num_spheres_x, int num_spheres_y)
 Enable creation of particles fixed to bottom container. More...
void EnableMovingPatch (std::shared_ptr< ChBody > body, double buffer_distance, double shift_distance, const ChVector3d &init_vel=ChVector3d())
 Enable moving patch and set parameters. More...
void EnableVisualization (bool val)
 Enable/disable visualization of boundaries (default: false).
bool IsVisualizationEnabled () const
std::shared_ptr< ChBodyGetGroundBody ()
 Return a handle to the ground body.
void Initialize (const ChVector3d &center, double length, double width, unsigned int num_layers, double radius, double density, const ChVector3d &init_vel=ChVector3d())
 Initialize the granular terrain system. More...
virtual void Synchronize (double time) override
 Update the state of the terrain system at the specified time.
double GetPatchFront () const
 Get current front boundary location (in positive X direction).
double GetPatchRear () const
 Get current rear boundary location (in negative X direction).
double GetPatchLeft () const
 Get left boundary location (in positive Y direction).
double GetPatchRight () const
 Get right boundary location (in negative Y direction).
double GetPatchBottom () const
 Get bottom boundary location.
bool PatchMoved () const
 Report if the patch was moved during the last call to Synchronize().
unsigned int GetNumParticles () const
 Get the number of particles.
virtual double GetHeight (const ChVector3d &loc) const override
 Get the terrain height below the specified location. More...
virtual chrono::ChVector3d GetNormal (const ChVector3d &loc) const override
 Get the terrain normal at the point below the specified location.
virtual float GetCoefficientFriction (const ChVector3d &loc) const override
 Get the terrain coefficient of friction at the point below the specified location. More...
- Public Member Functions inherited from chrono::vehicle::ChTerrain
virtual void Advance (double step)
 Advance the state of the terrain system by the specified duration.
virtual void GetProperties (const ChVector3d &loc, double &height, ChVector3d &normal, float &friction) const
 Get all terrain characteristics at the point below the specified location.
void RegisterHeightFunctor (std::shared_ptr< HeightFunctor > functor)
 Specify the functor object to provide the terrain height at given locations. More...
void RegisterNormalFunctor (std::shared_ptr< NormalFunctor > functor)
 Specify the functor object to provide the terrain normal at given locations. More...
void RegisterFrictionFunctor (std::shared_ptr< FrictionFunctor > functor)
 Specify the functor object to provide the coefficient of friction at given locations.


class BoundaryContact

Additional Inherited Members

- Protected Attributes inherited from chrono::vehicle::ChTerrain
std::shared_ptr< HeightFunctorm_height_fun
 functor for location-dependent terrain height
std::shared_ptr< NormalFunctorm_normal_fun
 functor for location-dependent terrain normal
std::shared_ptr< FrictionFunctorm_friction_fun
 functor for location-dependent coefficient of friction

Constructor & Destructor Documentation

◆ GranularTerrain()

chrono::vehicle::GranularTerrain::GranularTerrain ( ChSystem system)

Construct a default GranularTerrain.

The user is responsible for calling various Set methods before Initialize.

[in]systempointer to the containing multibody system

Member Function Documentation

◆ EnableMovingPatch()

void chrono::vehicle::GranularTerrain::EnableMovingPatch ( std::shared_ptr< ChBody body,
double  buffer_distance,
double  shift_distance,
const ChVector3d init_vel = ChVector3d() 

Enable moving patch and set parameters.

bodymonitored body
buffer_distancelook-ahead distance
shift_distancechunk size of relocated particles
init_velinitial particle velocity

◆ EnableRoughSurface()

void chrono::vehicle::GranularTerrain::EnableRoughSurface ( int  num_spheres_x,
int  num_spheres_y 

Enable creation of particles fixed to bottom container.

num_spheres_xnumber of fixed spheres in X direction
num_spheres_ynumber of fixed spheres in Y direction

◆ GetCoefficientFriction()

float chrono::vehicle::GranularTerrain::GetCoefficientFriction ( const ChVector3d loc) const

Get the terrain coefficient of friction at the point below the specified location.

This coefficient of friction value may be used by certain tire models to modify the tire characteristics, but it will have no effect on the interaction of the terrain with other objects (including tire models that do not explicitly use it). For GranularTerrain, this function defers to the user-provided functor object of type ChTerrain::FrictionFunctor, if one was specified. Otherwise, it returns the constant value specified through SetContactFrictionCoefficient.

Reimplemented from chrono::vehicle::ChTerrain.

◆ GetHeight()

double chrono::vehicle::GranularTerrain::GetHeight ( const ChVector3d loc) const

Get the terrain height below the specified location.

This function returns the highest point over all granular particles.

Reimplemented from chrono::vehicle::ChTerrain.

◆ Initialize()

void chrono::vehicle::GranularTerrain::Initialize ( const ChVector3d center,
double  length,
double  width,
unsigned int  num_layers,
double  radius,
double  density,
const ChVector3d init_vel = ChVector3d() 

Initialize the granular terrain system.

The granular material is created in successive layers within the specified volume, using the specified generator, until the number of particles exceeds the specified minimum value (see SetMinNumParticles). The initial particle locations are obtained with Poisson Disk sampling, using the given minimum separation distance.

[in]centercenter of bottom
[in]lengthpatch dimension in X direction
[in]widthpatch dimension in Y direction
[in]num_layersnumber of layers
[in]radiusparticle radius
[in]densityparticle density
[in]init_velparticle initial velocity

◆ SetCollisionEnvelope()

void chrono::vehicle::GranularTerrain::SetCollisionEnvelope ( double  envelope)

Set outward collision envelope.

This value is used for the internal custom collision detection for imposing boundary conditions. Note that if the underlying system is of SMC type (i.e., using a penalty-based contact method), the envelope is automatically set to 0. For NSC systems (i.e., when using a complementarity-based contact method), if the envelope is not specified, the default value is 5% of the particle radius.

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