Description
Base class for inertial properties (mass, moment of inertia) of beam sections of Cosserat type.
This can be shared between multiple beams.
#include <ChBeamSectionCosserat.h>
Public Member Functions | |
| virtual void | ComputeInertiaMatrix (ChMatrixNM< double, 6, 6 > &Mi)=0 |
| Compute the 6x6 sectional inertia matrix, as in {x_momentum,w_momentum}=[Mi]{xvel,wvel} The matrix is computed in the material reference (i.e. More... | |
| virtual void | ComputeInertiaDampingMatrix (ChMatrixNM< double, 6, 6 > &Ri, const ChVector<> &mW) |
| 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, i.e. More... | |
| virtual void | ComputeInertiaStiffnessMatrix (ChMatrixNM< double, 6, 6 > &Ki, const ChVector<> &mWvel, const ChVector<> &mWacc, const ChVector<> &mXacc) |
| 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 (ChVector<> &mF, ChVector<> &mT, const ChVector<> &mW)=0 |
| Compute the values of inertial force & torque depending on quadratic velocity terms, that is the gyroscopic torque and the centrifugal term (if any). More... | |
| virtual void | ComputeInertialForce (ChVector<> &mFi, ChVector<> &mTi, const ChVector<> &mWvel, const ChVector<> &mWacc, const ChVector<> &mXacc) |
| Compute the total inertial wrench, ie forces and torques (per unit length). More... | |
| virtual double | GetMassPerUnitLength ()=0 |
| Compute mass per unit length, ex.SI units [kg/m]. More... | |
Public Attributes | |
| ChBeamSectionCosserat * | section |
| 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... | |
Member Function Documentation
◆ ComputeInertiaDampingMatrix()
|
virtual |
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, i.e.
both linear and rotational coords assumed in the basis of the centerline reference. Default implementation: falls back to numerical differentiation of ComputeInertialForce to compute Ri, please override this if analytical formula of Ri is known!
- Parameters
-
Ri 6x6 sectional inertial-damping (gyroscopic damping) matrix here mW current angular velocity of section, in material frame
Reimplemented in chrono::fea::ChInertiaCosseratAdvanced, and chrono::fea::ChInertiaCosseratSimple.
◆ ComputeInertialForce()
|
virtual |
Compute the total inertial wrench, ie forces and torques (per unit length).
Note: both force and torque are returned in the basis of the material frame (not the absolute frame!), ex. to apply it to a Chrono body, the force must be rotated to absolute basis. Default implementation: falls back to Fi = [Mi]*{xacc,wacc}+{mF,mT} where [Mi] is given by ComputeInertiaMatrix() and {F_quad,T_quad} are given by ComputeQuadraticTerms(), i.e. gyro and centrif.terms. For faster implementations one can override this, ex. avoid doing the [Mi] matrix product.
- Parameters
-
mFi total inertial force returned here, in basis of material frame mTi total inertial torque returned here, in basis of material frame mWvel current angular velocity of section, in material frame mWacc current angular acceleration of section, in material frame mXacc current acceleration of section, in material frame (not absolute!)
◆ ComputeInertiaMatrix()
|
pure virtual |
Compute the 6x6 sectional inertia matrix, as in {x_momentum,w_momentum}=[Mi]{xvel,wvel} The matrix is computed in the material reference (i.e.
it is the sectional mass matrix)
- Parameters
-
Mi 6x6 sectional mass matrix here
Implemented in chrono::fea::ChInertiaCosseratSimple, and chrono::fea::ChInertiaCosseratAdvanced.
◆ ComputeInertiaStiffnessMatrix()
|
virtual |
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. Default implementation: falls back to numerical differentiation of ComputeInertialForce to compute Ki^, please override this if analytical formula of Ki^ is known!
- Parameters
-
Ki 6x6 sectional inertial-stiffness matrix [Ki^] here mWvel current angular velocity of section, in material frame mWacc current angular acceleration of section, in material frame mXacc current acceleration of section, in material frame (not absolute!)
Reimplemented in chrono::fea::ChInertiaCosseratAdvanced, and chrono::fea::ChInertiaCosseratSimple.
◆ ComputeQuadraticTerms()
|
pure virtual |
Compute the values of inertial force & torque depending on quadratic velocity terms, that is the gyroscopic torque and the centrifugal term (if any).
All terms expressed in the material reference, ie. the reference in the centerline of the section.
- Parameters
-
mF centrifugal term (if any) returned here mT gyroscopic term returned here mW current angular velocity of section, in material frame
Implemented in chrono::fea::ChInertiaCosseratAdvanced, and chrono::fea::ChInertiaCosseratSimple.
◆ GetMassPerUnitLength()
|
pure virtual |
Compute mass per unit length, ex.SI units [kg/m].
This is also the(0, 0) element in the sectional inertia matrix.
Implemented in chrono::fea::ChInertiaCosseratAdvanced, and chrono::fea::ChInertiaCosseratSimple.
Member Data Documentation
◆ compute_inertia_damping_matrix
| bool chrono::fea::ChInertiaCosserat::compute_inertia_damping_matrix = true |
Flag that turns on/off the computation of the [Ri] 'gyroscopic' inertial damping matrix.
If false, Ri=0. Can be used for cpu speedup, profiling, tests. Default: true.
◆ compute_inertia_stiffness_matrix
| bool chrono::fea::ChInertiaCosserat::compute_inertia_stiffness_matrix = true |
Flag that turns on/off the computation of the [Ki] inertial stiffness matrix.
If false, Ki=0. Can be used for cpu speedup, profiling, tests. Default: true.
◆ compute_Ri_Ki_by_num_diff
| bool chrono::fea::ChInertiaCosserat::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.
Children calsses must take care of this. Default: false.
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
