Lumped plasticity of Cosserat-type beams.

This defines 6 independent yelds for the six generalized forces/moments in the beam. Note that this is a rough approximation of plasticity in beams for at least two main reasons: it cannot capture how plastic zones are made inside a section (which is mostly important when cycling with back and forth bending), and it does not capture coupled My+Mz effects, or Nx+My or Nx+Mz as often happens. Briefly: use it if plasticization happens in a scenario of pure bending on a single xy or xz plane, or pure compression/extension, or pure torsion. This can be shared between multiple beams.

#include <ChBeamSectionCosserat.h>

Inheritance diagram for chrono::fea::ChPlasticityCosseratLumped:
Collaboration diagram for chrono::fea::ChPlasticityCosseratLumped:

Public Member Functions

 ChPlasticityCosseratLumped ()
 Default constructor: linear isotropic constant hardening.
virtual bool ComputeStressWithReturnMapping (ChVector<> &stress_n, ChVector<> &stress_m, ChVector<> &e_strain_e_new, ChVector<> &e_strain_k_new, ChBeamMaterialInternalData &data_new, const ChVector<> &tot_strain_e, const ChVector<> &tot_strain_k, const ChBeamMaterialInternalData &data) override
 Given a trial strain, it computes the effective stress and strain by clamping against the yeld surface. More...
virtual void CreatePlasticityData (int numpoints, std::vector< std::unique_ptr< ChBeamMaterialInternalData >> &plastic_data) override
- Public Member Functions inherited from chrono::fea::ChPlasticityCosserat
virtual void ComputeStiffnessMatrixElastoplastic (ChMatrixNM< double, 6, 6 > &K, const ChVector<> &strain_e, const ChVector<> &strain_k, const ChBeamMaterialInternalData &data)
 Compute the 6x6 tangent material stiffness matrix [Km] = dσ/dε, given actual internal data and deformation and curvature (if needed). More...

Public Attributes

std::shared_ptr< ChFunctionn_yeld_x
std::shared_ptr< ChFunctionn_beta_x
std::shared_ptr< ChFunctionn_yeld_y
std::shared_ptr< ChFunctionn_beta_y
std::shared_ptr< ChFunctionn_yeld_z
std::shared_ptr< ChFunctionn_beta_z
std::shared_ptr< ChFunctionn_yeld_Mx
std::shared_ptr< ChFunctionn_beta_Mx
std::shared_ptr< ChFunctionn_yeld_My
std::shared_ptr< ChFunctionn_beta_My
std::shared_ptr< ChFunctionn_yeld_Mz
std::shared_ptr< ChFunctionn_beta_Mz
- Public Attributes inherited from chrono::fea::ChPlasticityCosserat
double nr_yeld_tolerance
int nr_yeld_maxiters

Member Function Documentation

◆ ComputeStressWithReturnMapping()

bool chrono::fea::ChPlasticityCosseratLumped::ComputeStressWithReturnMapping ( ChVector<> &  stress_n,
ChVector<> &  stress_m,
ChVector<> &  e_strain_e_new,
ChVector<> &  e_strain_k_new,
ChBeamMaterialInternalData data_new,
const ChVector<> &  tot_strain_e,
const ChVector<> &  tot_strain_k,
const ChBeamMaterialInternalData data 

Given a trial strain, it computes the effective stress and strain by clamping against the yeld surface.

An implicit return mapping integration step is computed automatically per each call of this function. Returns true if it had to do return mapping, false if it was in elastic regime

stress_nlocal stress (generalized force), x component = traction along beam
stress_mlocal stress (generalized torque), x component = torsion torque along beam
e_strain_e_newupdated elastic strain (deformation part)
e_strain_k_newupdated elastic strain (curvature part)
data_newupdated material internal variables, at this point, including {p_strain_e, p_strain_k, p_strain_acc}
tot_strain_etrial tot strain (deformation part): x= elongation, y and z are shear
tot_strain_ktrial tot strain (curvature part), x= torsion, y and z are line curvatures
datacurrent material internal variables, at this point, including {p_strain_e, p_strain_k, p_strain_acc}

Implements chrono::fea::ChPlasticityCosserat.

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