DampingModel< T > Class Template Reference

Detailed Description

template<typename T>
class drake::multibody::fem::DampingModel< T >

A viscous Rayleigh damping model in which the damping matrix D is a linear combination of mass and stiffness matrices, as, D = αM + βK where α and β are nonnegative.

The damping ratio ζ for a given natural frequency ωₙ of a mode of vibration can be calculated as ζ = (α/ωₙ + βωₙ)/2. Notice the contribution of the stiffness term βK to the damping matrix D causes ζ to be proportional to a mode's natural frequency ωₙ whereas the contribution of the mass term αM to the damping matrix D causes ζ to be inversely proportional to a mode's natural frequency ωₙ. In the context of rigid body motion (ωₙ = 0), only the αM term contributes to the damping matrix D, hence if rigid body motion (or low value of ωₙ) is expected, α should be kept small. One way to determine numerical values for α and β is to somehow obtain reasonable estimates of the range of ωₙ, and then choose numerical values for ζ (e.g 0 ≤ ζ < 0.05). Thereafter calculate the associated numerical values of α and β.

Template Parameters

T	The scalar type, which must be one of the default nonsymbolic scalars.

#include <drake/multibody/fem/damping_model.h>

Public Member Functions
	DampingModel (const T &mass_coeff_alpha, const T &stiffness_coeff_beta)
	Constructs a Rayleigh damping model by storing the mass coefficient α and the stiffness coefficient β that appears in the damping matrix D = αM + βK. More...
const T &	mass_coeff_alpha () const
const T &	stiffness_coeff_beta () const
Implements CopyConstructible, CopyAssignable, MoveConstructible, MoveAssignable
	DampingModel (const DampingModel &)=default
DampingModel &	operator= (const DampingModel &)=default
	DampingModel (DampingModel &&)=default
DampingModel &	operator= (DampingModel &&)=default

Constructor & Destructor Documentation

DampingModel() [1/3]

DampingModel ( const DampingModel< T > &  )

default

DampingModel() [2/3]

DampingModel ( DampingModel< T > &&  )

default

DampingModel() [3/3]

DampingModel	(	const T &	mass_coeff_alpha,
		const T &	stiffness_coeff_beta
	)

Constructs a Rayleigh damping model by storing the mass coefficient α and the stiffness coefficient β that appears in the damping matrix D = αM + βK.

Exceptions

std::exception

if either mass_coeff_alpha or stiffness_coeff_beta is negative.

Member Function Documentation

mass_coeff_alpha()

const T& mass_coeff_alpha

(

)

const

operator=() [1/2]

DampingModel& operator= ( DampingModel< T > &&  )

default

operator=() [2/2]

DampingModel& operator= ( const DampingModel< T > &  )

default

stiffness_coeff_beta()

const T& stiffness_coeff_beta

(

)

const

---

The documentation for this class was generated from the following file:

• drake/multibody/fem/damping_model.h