chrono::fea::ChInertiaCosseratAdvanced Class Reference

Description

Inertia properties of a beam of Cosserat type, not necessarily of uniform density, from the following information that allows the center of mass to be offset respect to the beam centerline:

  • a mass per unit length
  • offset of the center of mass Cm along Y Z section axes,
  • Jyy Jzz Jzy moments of inertia computed in section reference Y Z, not rotated and origin in centerline The polar moment of area is automatically inferred via perpendicular axis theorem.

#include <ChBeamSectionCosserat.h>

Inheritance diagram for chrono::fea::ChInertiaCosseratAdvanced:
Collaboration diagram for chrono::fea::ChInertiaCosseratAdvanced:

Public Member Functions

 ChInertiaCosseratAdvanced (double mu_density, double c_y, double c_z, double Jyy_moment, double Jzz_moment, double Jyz_moment)
 
 ChInertiaCosseratAdvanced (double mu_density, double c_y, double c_z, ChVector3d Ivals)
 
virtual void ComputeInertiaMatrix (ChMatrix66d &M) override
 Compute the 6x6 sectional inertia matrix, as in {x_momentum,w_momentum}=[Mi]{xvel,wvel} The matrix is computed in the material reference.
 
virtual void ComputeInertiaDampingMatrix (ChMatrix66d &Ri, const ChVector3d &mW) override
 Compute the 6x6 sectional inertia damping matrix [Ri] (gyroscopic matrix damping), as in linearization dFi=[Mi]*d{xacc,wacc}+[Ri]*d{xvel,wvel}+[Ki]*d{pos,rot} The matrix is computed in the material reference. More...
 
virtual void ComputeInertiaStiffnessMatrix (ChMatrix66d &Ki, const ChVector3d &mWvel, const ChVector3d &mWacc, const ChVector3d &mXacc) override
 Compute the 6x6 sectional inertia stiffness matrix [Ki^], as in linearization dFi=[Mi]*d{xacc,wacc}+[Ri]*d{xvel,wvel}+[Ki]*d{pos,rot} The matrix is computed in the material reference. More...
 
virtual void ComputeQuadraticTerms (ChVector3d &mF, ChVector3d &mT, const ChVector3d &mW) override
 Compute the values of inertial force & torque depending on quadratic velocity terms, that is the gyroscopic torque w x [J]w and the centrifugal term (if center of mass is offset). More...
 
virtual double GetMassPerUnitLength () override
 Get mass per unit length, ex.SI units [kg/m].
 
virtual void SetMassPerUnitLength (double mmu)
 Set mass c, ex.SI units [kg/m]. More...
 
void SetCenterOfMass (double my, double mz)
 "mass reference": set the displacement of the center of mass respect to the section centerline reference.
 
double GetCenterOfMassY ()
 
double GetCenterOfMassZ ()
 
virtual void SetInertiasPerUnitLength (double Jyy_moment, double Jzz_moment, double Jyz_moment)
 Set inertia moments, assumed computed in the Y Z unrotated reference frame of the section at centerline, and defined as: \( J_{yy} = \int_\Omega \rho z^2 d\Omega \), also Jyy = Mm(4,4) \( J_{zz} = \int_\Omega \rho y^2 d\Omega \), also Jzz = Mm(5,5) \( J_{yz} = \int_\Omega \rho y z d\Omega \), also Jyz = -Mm(4,5) = -Mm(5,4) Note that for an uniform density, these are also related to second moments of area as \( J_{yy} = \rho I_{yy} \), \( J_{zz} = \rho I_{zz} \). More...
 
virtual double GetInertiaJxxPerUnitLength ()
 Get the Jxx component of the inertia per unit length (polar inertia), in the Y Z unrotated reference frame of the section at centerline. More...
 
virtual double GetInertiaJyyPerUnitLength ()
 Get the Jyy component of the inertia per unit length, in the Y Z unrotated reference frame of the section at centerline, also Jyy = Mm(4,4)
 
virtual double GetInertiaJzzPerUnitLength ()
 Get the Jzz component of the inertia per unit length, in the Y Z unrotated reference frame of the section at centerline, also Jzz = Mm(5,5)
 
virtual double GetInertiaJyzPerUnitLength ()
 Get the Jyz off-diagonal component of the inertia per unit length, in the Y Z unrotated reference frame of the section at centerline. More...
 
virtual void SetMainInertiasInMassReference (double Jmyy, double Jmzz, double phi)
 Set inertia moments, per unit length, as assumed computed in the Ym Zm "mass reference" frame, ie. More...
 
virtual void GetMainInertiasInMassReference (double &Jmyy, double &Jmzz, double &phi)
 Get inertia moments, per unit length, as assumed computed in the Ym Zm "mass reference" frame, and the rotation phi of that frame, ie. More...
 
- Public Member Functions inherited from chrono::fea::ChInertiaCosserat
virtual void ComputeInertialForce (ChVector3d &mFi, ChVector3d &mTi, const ChVector3d &mWvel, const ChVector3d &mWacc, const ChVector3d &mXacc)
 Compute the total inertial wrench, ie forces and torques (per unit length). More...
 

Additional Inherited Members

- Public Attributes inherited from chrono::fea::ChInertiaCosserat
ChBeamSectionCosseratsection
 
bool compute_inertia_damping_matrix = true
 Flag that turns on/off the computation of the [Ri] 'gyroscopic' inertial damping matrix. More...
 
bool compute_inertia_stiffness_matrix = true
 Flag that turns on/off the computation of the [Ki] inertial stiffness matrix. More...
 
bool compute_Ri_Ki_by_num_diff = false
 Flag for computing the Ri and Ki matrices via numerical differentiation even if an analytical expression is provided. More...
 

Constructor & Destructor Documentation

◆ ChInertiaCosseratAdvanced() [1/2]

chrono::fea::ChInertiaCosseratAdvanced::ChInertiaCosseratAdvanced ( double  mu_density,
double  c_y,
double  c_z,
double  Jyy_moment,
double  Jzz_moment,
double  Jyz_moment 
)
inline
Parameters
mu_densitymass per unit length [kg/m]
c_ydisplacement of center of mass along Y
c_zdisplacement of center of mass along Z
Jyy_momentmoment of inertia per unit length, about Y. Jyy=Mm(4,4)
Jzz_momentmoment of inertia per unit length, about Z. Jzz=Mm(5,5)
Jyz_momentmoment of inertia per unit length, about YZ (off diagonal term). Jyz=-Mm(4,5)=-Mm(5,4)

◆ ChInertiaCosseratAdvanced() [2/2]

chrono::fea::ChInertiaCosseratAdvanced::ChInertiaCosseratAdvanced ( double  mu_density,
double  c_y,
double  c_z,
ChVector3d  Ivals 
)
inline
Parameters
mu_densitymass per unit length [kg/m]
c_ydisplacement of center of mass along Y
c_zdisplacement of center of mass along Z
Ivalsmoments of inertia

Member Function Documentation

◆ ComputeInertiaDampingMatrix()

void chrono::fea::ChInertiaCosseratAdvanced::ComputeInertiaDampingMatrix ( ChMatrix66d Ri,
const ChVector3d mW 
)
overridevirtual

Compute the 6x6 sectional inertia damping matrix [Ri] (gyroscopic matrix damping), as in linearization dFi=[Mi]*d{xacc,wacc}+[Ri]*d{xvel,wvel}+[Ki]*d{pos,rot} The matrix is computed in the material reference.

Parameters
Ri6x6 sectional inertial-damping (gyroscopic damping) matrix values here
mWcurrent angular velocity of section, in material frame

Reimplemented from chrono::fea::ChInertiaCosserat.

◆ ComputeInertiaStiffnessMatrix()

void chrono::fea::ChInertiaCosseratAdvanced::ComputeInertiaStiffnessMatrix ( ChMatrix66d Ki,
const ChVector3d mWvel,
const ChVector3d mWacc,
const ChVector3d mXacc 
)
overridevirtual

Compute the 6x6 sectional inertia stiffness matrix [Ki^], as in linearization dFi=[Mi]*d{xacc,wacc}+[Ri]*d{xvel,wvel}+[Ki]*d{pos,rot} The matrix is computed in the material reference.

NOTE the matrix already contains the 'geometric' stiffness, so it transforms to absolute transl/local rot just like [Mi] and [Ri]: [Ki]_al =[R,0;0,I]*[Ki^]*[R',0;0,I'] , with [Ki^]=([Ki]+[0,f~';0,0]) for f=current force part of inertial forces.

Parameters
Ki6x6 sectional inertial-stiffness matrix [Ki^] values here
mWvelcurrent angular velocity of section, in material frame
mWacccurrent angular acceleration of section, in material frame
mXacccurrent acceleration of section, in material frame (not absolute!)

Reimplemented from chrono::fea::ChInertiaCosserat.

◆ ComputeQuadraticTerms()

void chrono::fea::ChInertiaCosseratAdvanced::ComputeQuadraticTerms ( ChVector3d mF,
ChVector3d mT,
const ChVector3d mW 
)
overridevirtual

Compute the values of inertial force & torque depending on quadratic velocity terms, that is the gyroscopic torque w x [J]w and the centrifugal term (if center of mass is offset).

All terms expressed in the material reference, ie. the reference in the centerline of the section.

Parameters
mFcentrifugal term (if any) returned here
mTgyroscopic term returned here
mWcurrent angular velocity of section, in material frame

Implements chrono::fea::ChInertiaCosserat.

◆ GetInertiaJxxPerUnitLength()

virtual double chrono::fea::ChInertiaCosseratAdvanced::GetInertiaJxxPerUnitLength ( )
inlinevirtual

Get the Jxx component of the inertia per unit length (polar inertia), in the Y Z unrotated reference frame of the section at centerline.

Note: it automatically follows Jxx=Jyy+Jzz for the polar theorem.

◆ GetInertiaJyzPerUnitLength()

virtual double chrono::fea::ChInertiaCosseratAdvanced::GetInertiaJyzPerUnitLength ( )
inlinevirtual

Get the Jyz off-diagonal component of the inertia per unit length, in the Y Z unrotated reference frame of the section at centerline.

Also Jyz = -Mm(4,5) = -Mm(5,4)

◆ GetMainInertiasInMassReference()

void chrono::fea::ChInertiaCosseratAdvanced::GetMainInertiasInMassReference ( double &  Jmyy,
double &  Jmzz,
double &  phi 
)
virtual

Get inertia moments, per unit length, as assumed computed in the Ym Zm "mass reference" frame, and the rotation phi of that frame, ie.

inertias centered at the center of mass and rotated by phi angle to match the main axes of inertia: \( Jm_{yy} = \int_\Omega \rho z_{m}^2 d\Omega \), \( Jm_{zz} = \int_\Omega \rho y_{m}^2 d\Omega \). Assuming the center of mass is already set.

Reimplemented in chrono::fea::ChInertiaCosseratMassref.

◆ SetInertiasPerUnitLength()

void chrono::fea::ChInertiaCosseratAdvanced::SetInertiasPerUnitLength ( double  Jyy_moment,
double  Jzz_moment,
double  Jyz_moment 
)
virtual

Set inertia moments, assumed computed in the Y Z unrotated reference frame of the section at centerline, and defined as: \( J_{yy} = \int_\Omega \rho z^2 d\Omega \), also Jyy = Mm(4,4) \( J_{zz} = \int_\Omega \rho y^2 d\Omega \), also Jzz = Mm(5,5) \( J_{yz} = \int_\Omega \rho y z d\Omega \), also Jyz = -Mm(4,5) = -Mm(5,4) Note that for an uniform density, these are also related to second moments of area as \( J_{yy} = \rho I_{yy} \), \( J_{zz} = \rho I_{zz} \).

Note also that \( J_{xy} = J_{xz} = J_{yx} = J_{zx} = 0 \) anyway. Note also that \( J_{xy} \) does not need to be input, as automatically computed via \( J_{xx} = J_{yy} +J_{zz} \) for the polar theorem.

Reimplemented in chrono::fea::ChInertiaCosseratMassref.

◆ SetMainInertiasInMassReference()

void chrono::fea::ChInertiaCosseratAdvanced::SetMainInertiasInMassReference ( double  Jmyy,
double  Jmzz,
double  phi 
)
virtual

Set inertia moments, per unit length, as assumed computed in the Ym Zm "mass reference" frame, ie.

centered at the center of mass and rotated by phi angle to match the main axes of inertia: \( Jm_{yy} = \int_\Omega \rho z_{m}^2 d\Omega \), \( Jm_{zz} = \int_\Omega \rho y_{m}^2 d\Omega \). Assuming the center of mass is already set.

Reimplemented in chrono::fea::ChInertiaCosseratMassref.

◆ SetMassPerUnitLength()

virtual void chrono::fea::ChInertiaCosseratAdvanced::SetMassPerUnitLength ( double  mmu)
inlinevirtual

Set mass c, ex.SI units [kg/m].

Note that for uniform volumetric density \( \rho \), and area \( A \), this is also \( \mu = \rho A \).


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