Perform thermal analysis (demo_FEA_thermal.cpp)

Tutorial that teaches how to use the FEA module to compute the scalar temperature field in a solid (Poisson problem) given boundary conditions.

// =============================================================================
// Copyright (c) 2014
// All rights reserved.
// Use of this source code is governed by a BSD-style license that can be found
// in the LICENSE file at the top level of the distribution and at
// =============================================================================
// Authors: Alessandro Tasora
// =============================================================================
// FEA visualization using Irrlicht
// =============================================================================
#include "chrono/physics/ChSystemSMC.h"
#include "chrono/solver/ChIterativeSolverLS.h"
#include "chrono/fea/ChElementBar.h"
#include "chrono/fea/ChElementTetra_4.h"
#include "chrono/fea/ChElementTetra_10.h"
#include "chrono/fea/ChElementHexa_8.h"
#include "chrono/fea/ChElementHexa_20.h"
#include "chrono/fea/ChContinuumThermal.h"
#include "chrono/fea/ChContinuumElectrostatics.h"
#include "chrono/fea/ChNodeFEAxyzP.h"
#include "chrono/fea/ChMesh.h"
#include "chrono/fea/ChMeshFileLoader.h"
#include "chrono/fea/ChLinkPointFrame.h"
#include "chrono/fea/ChVisualizationFEAmesh.h"
#include "chrono_irrlicht/ChIrrApp.h"
// Remember to use the namespace 'chrono' because all classes
// of Chrono::Engine belong to this namespace and its children...
using namespace chrono;
using namespace chrono::fea;
using namespace chrono::irrlicht;
using namespace irr;
int main(int argc, char* argv[]) {
GetLog() << "Copyright (c) 2017\nChrono version: " << CHRONO_VERSION << "\n\n";
// Create a Chrono::Engine physical system
ChSystemSMC my_system;
// Create the Irrlicht visualization (open the Irrlicht device,
// bind a simple user interface, etc. etc.)
ChIrrApp application(&my_system, L"FEM thermal", core::dimension2d<u32>(800, 600));
// Easy shortcuts to add camera, lights, logo and sky in Irrlicht scene:
application.AddTypicalLights(core::vector3df(20, 20, 20), core::vector3df(-20, 20, -20), 90, 90,
irr::video::SColorf(0.5, 0.5, 0.5));
application.AddTypicalCamera(core::vector3df(0, (f32)0.7, -1), core::vector3df(0, (f32)0.4, 0));
// Create a mesh, that is a container for groups
// of elements and their referenced nodes.
auto my_mesh = chrono_types::make_shared<ChMesh>();
// Create a material, that must be assigned to each element,
// and set its parameters
auto mmaterial = chrono_types::make_shared<ChContinuumThermal>();
// Add some TETAHEDRONS:
// Load a .node file and a .ele file from disk, defining a complicate tetrahedron mesh.
// This is much easier than creating all nodes and elements via C++ programming.
// You can generate these files using the TetGen tool.
try {
ChMeshFileLoader::FromTetGenFile(my_mesh, GetChronoDataFile("fea/beam.node").c_str(),
GetChronoDataFile("fea/beam.ele").c_str(), mmaterial);
} catch (ChException myerr) {
GetLog() << myerr.what();
return 0;
for (unsigned int inode = 0; inode < my_mesh->GetNnodes(); ++inode) {
if (auto mnode = std::dynamic_pointer_cast<ChNodeFEAxyzP>(my_mesh->GetNode(inode))) {
mnode->SetPos(mnode->GetPos() * ChVector<>(3, 1, 3));
// Set some BOUNDARY CONDITIONS on nodes:
// Impose load on the 180th node
auto mnode3 = std::dynamic_pointer_cast<ChNodeFEAxyzP>(my_mesh->GetNode(180));
mnode3->SetF(20); // thermal load: heat flux [W] into node
// Impose field on two top nodes (remember the SetFixed(true); )
auto mnode1 = std::dynamic_pointer_cast<ChNodeFEAxyzP>(my_mesh->GetNode(my_mesh->GetNnodes() - 1));
mnode1->SetP(0.5); // field: temperature [K]
auto mnode2 = std::dynamic_pointer_cast<ChNodeFEAxyzP>(my_mesh->GetNode(my_mesh->GetNnodes() - 2));
mnode2->SetP(0.5); // field: temperature [K]
// Impose field on the base points:
for (unsigned int inode = 0; inode < my_mesh->GetNnodes(); ++inode) {
if (auto mnode = std::dynamic_pointer_cast<ChNodeFEAxyzP>(my_mesh->GetNode(inode))) {
if (mnode->GetPos().y() < 0.01) {
mnode->SetP(10); // field: temperature [K]
// Remember to add the mesh to the system!
// ==Asset== attach a visualization of the FEM mesh.
// This will automatically update a triangle mesh (a ChTriangleMeshShape
// asset that is internally managed) by setting proper
// coordinates and vertex colors as in the FEM elements.
// Such triangle mesh can be rendered by Irrlicht or POVray or whatever
// postprocessor that can handle a colored ChTriangleMeshShape).
// Do not forget AddAsset() at the end!
// This will paint the colored mesh with temperature scale (E_PLOT_NODE_P is the scalar field of the Poisson
// problem)
auto mvisualizemesh = chrono_types::make_shared<ChVisualizationFEAmesh>(*(my_mesh.get()));
mvisualizemesh->SetColorscaleMinMax(-1, 12);
mvisualizemesh->SetShrinkElements(false, 0.85);
// This will paint the wireframe
auto mvisualizemeshB = chrono_types::make_shared<ChVisualizationFEAmesh>(*(my_mesh.get()));
// This will paint the heat flux as line vectors
auto mvisualizemeshC = chrono_types::make_shared<ChVisualizationFEAmesh>(*(my_mesh.get()));
mvisualizemeshC->SetDefaultSymbolsColor(ChColor(0.1f, 0.2f, 0.2f));
// ==IMPORTANT!== Use this function for adding a ChIrrNodeAsset to all items
// in the system. These ChIrrNodeAsset assets are 'proxies' to the Irrlicht meshes.
// If you need a finer control on which item really needs a visualization proxy in
// Irrlicht, just use application.AssetBind(myitem); on a per-item basis.
// ==IMPORTANT!== Use this function for 'converting' into Irrlicht meshes the assets
// that you added to the bodies into 3D shapes, they can be visualized by Irrlicht!
// Use MINRES solver to handle stiffness matrices.
auto solver = chrono_types::make_shared<ChSolverMINRES>();
solver->EnableWarmStart(true); // IMPORTANT for convergence when using EULER_IMPLICIT_LINEARIZED
my_system.SetTimestepperType(ChTimestepper::Type::EULER_IMPLICIT_LINEARIZED); // fast, less precise
// Note: if you are interested only in a single LINEAR STATIC solution
// (not a transient thermal solution, but rather the steady-state solution),
// at this point you can uncomment the following line:
// my_system.DoStaticLinear();
// Also, in the following while() loop, remove application.DoStep();
// so you can spin the 3D view and look at the solution.
while (application.GetDevice()->run()) {
if (my_system.GetChTime() > 5)
// Print some node temperatures..
for (unsigned int inode = 0; inode < my_mesh->GetNnodes(); ++inode) {
if (auto mnode = std::dynamic_pointer_cast<ChNodeFEAxyzP>(my_mesh->GetNode(inode))) {
if (mnode->GetPos().x() < 0.01) {
GetLog() << "Node at y=" << mnode->GetPos().y() << " has T=" << mnode->GetP() << "\n";
return 0;
std::string GetChronoDataFile(const std::string &filename)
Obtain the complete path to the specified filename, given relative to the Chrono data directory (thre...
Definition: ChGlobal.cpp:95
void Add(std::shared_ptr< ChPhysicsItem > item)
Attach an arbitrary ChPhysicsItem (e.g.
Definition: ChSystem.cpp:146
Class for exceptions for throw() catch() mechanism.
Definition: ChException.h:25
void AssetUpdateAll()
For all items in a ChSystem, this function sets up the Irrlicht nodes corresponding to the geometric ...
Definition: ChIrrApp.cpp:50
ChLog & GetLog()
Global function to get the current ChLog object.
Definition: ChLog.cpp:39
void SetTimestep(double val)
Set/Get the time step for time integration.
Definition: ChIrrAppInterface.cpp:552
Class to add some GUI to Irrlicht+ChronoEngine applications.
Definition: ChIrrApp.h:29
virtual void EndScene()
Call this to end the scene draw at the end of each animation frame.
Definition: ChIrrAppInterface.cpp:627
Class for setting a color (used by ChVisualization)
Definition: ChColor.h:25
Definition of general purpose 3d vector variables, such as points in 3D.
Definition: ChVector.h:35
virtual void DoStep()
Call this function inside a loop such as.
Definition: ChIrrAppInterface.cpp:637
static void FromTetGenFile(std::shared_ptr< ChMesh > mesh, const char *filename_node, const char *filename_ele, std::shared_ptr< ChContinuumMaterial > my_material, ChVector<> pos_transform=VNULL, ChMatrix33<> rot_transform=ChMatrix33<>(1))
Load tetrahedrons from .node and .ele files as saved by TetGen.
Definition: ChMeshFileLoader.cpp:39
Class for a physical system in which contact is modeled using a smooth (penalty-based) method.
Definition: ChSystemSMC.h:31
virtual void SetSolver(std::shared_ptr< ChSolver > newsolver)
Attach a solver (derived from ChSolver) for use by this system.
Definition: ChSystem.cpp:270
void AssetBindAll()
Shortcut to add and bind a ChIrrNodeAsset to all items in a ChSystem.
Definition: ChIrrApp.cpp:42
virtual void BeginScene(bool backBuffer=true, bool zBuffer=true, irr::video::SColor color=irr::video::SColor(255, 0, 0, 0))
Call this to clean the canvas at the beginning of each animation frame.
Definition: ChIrrAppInterface.cpp:610
Main namespace for the Chrono package.
Definition: ChAsset.cpp:18
double GetChTime() const
Get the simulation time of this system.
Definition: ChSystem.h:230
void SetTimestepperType(ChTimestepper::Type type)
Set the method for time integration (time stepper type).
Definition: ChSystem.cpp:348
virtual void DrawAll()
Call this function inside a loop such as.
Definition: ChIrrAppInterface.cpp:750
Namespace for FEA classes.
Definition: ChChrono.h:52