Module with subroutines for friction calculations. More...

Data Types
interface	findforceinfriction
	Computes the total applied force in a joint dof with friction. More...

Functions/Subroutines
subroutine, public	updatefrictions (joints, cElems, dt, iter, useRealVel, ierr)
	Updates the friction forces in all joints and contact elements. More...

subroutine	updatefriction (ierr, dt, deltaT, friction, jDof, joint, cElem)
	Updates friction forces in the given joint or contact element. More...

subroutine	updatemultidoffriction (ierr, dt, deltaT, friction, joint)
	Updates multidof friction forces in the given joint. More...

subroutine	findmaxfrictionforce (Fmax, Fequ, Fext, Vel, StickSlip, F0, Coulomb, Stribeck, Vc)
	Calculates the maximum friction force. More...

subroutine	findfrictionforce (Ffric, Kfric, Xn_1, Vn_1, Fold, dF, lStick, lInit, dT, Fmax, Fext, Ftol, X0, Xn, Vn)
	Calculates the actual friction force. More...

subroutine, public	addinfrictionforces (joint, sam, SysForce, SysReac, ierr)
	Adds friction forces for a joint into the given system vectors. More...

subroutine	findjointforceinfriction (joint, sam, RF, Q, Fs, Fd, Fi)
	Computes the total applied force in a joint DOF with friction. More...

subroutine	findcontactelmforceinfriction (cElem, sam, RF, Q, Fs, Fd, Fi)
	Computes total applied force in a contact element DOF with friction. More...

Detailed Description

Module with subroutines for friction calculations.

Function/Subroutine Documentation

◆ addinfrictionforces()

subroutine, public frictionroutinesmodule::addinfrictionforces	(	type(masterslavejointtype), intent(in)	joint,
		type(samtype), intent(in)	sam,
		real(dp), dimension(:), intent(inout)	SysForce,
		real(dp), dimension(:), intent(inout)	SysReac,
		integer, intent(inout)	ierr
	)

Adds friction forces for a joint into the given system vectors.

Parameters

[in]	joint	The joint owning this friction force
[in]	sam	Data for managing system matrix assembly
	SysForce	System load vector to receive the force contribution
	SysReac	Reaction force container
	ierr	Error flag

Author: Bjorn Haugen

Date: Nov 2001

Author: Knut Morten Okstad

Date: 25 Jun 2002

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◆ findcontactelmforceinfriction()

subroutine frictionroutinesmodule::findcontactelmforceinfriction	(	type(contactelementtype), intent(inout)	cElem,
		type(samtype), intent(in)	sam,
		real(dp), dimension(:), intent(in)	RF,
		real(dp), dimension(:), intent(in)	Q,
		real(dp), dimension(:), intent(in)	Fs,
		real(dp), dimension(:), intent(in), optional	Fd,
		real(dp), dimension(:), intent(in), optional	Fi
	)

Computes total applied force in a contact element DOF with friction.

Parameters

	cElem	The contact element to check for friction forces.
[in]	sam	Data for managing system matrix assembly
[in]	RF	Reaction force container
[in]	Q	External force system vector
[in]	Fs	Stiffness force system vector
[in]	Fd	Damping force system vector
[in]	Fi	Inertia force system vector

The total applies force is equal to the sum of all force contributions to the friction DOF, except for the friction force itself.

Todo:: This subroutine is not implemented yet. Currently does nothing.

Author: Knut Morten Okstad

Date: 17 Sep 2007

◆ findfrictionforce()

subroutine frictionroutinesmodule::findfrictionforce	(	real(dp), intent(out)	Ffric,
		real(dp), intent(inout)	Kfric,
		real(dp), intent(inout)	Xn_1,
		real(dp), intent(inout)	Vn_1,
		real(dp), intent(inout)	Fold,
		real(dp), intent(inout)	dF,
		integer, intent(inout)	lStick,
		integer, intent(inout)	lInit,
		real(dp), intent(in)	dT,
		real(dp), intent(in)	Fmax,
		real(dp), intent(in)	Fext,
		real(dp), intent(in)	Ftol,
		real(dp), intent(in)	X0,
		real(dp), intent(in)	Xn,
		real(dp), intent(in)	Vn
	)

Calculates the actual friction force.

Parameters

[out]	Ffric	Current friction force
	Kfric	Relative change in friction force wrt. velocity
	Xn_1	Position at previous iteration
	Vn_1	Velocity at previous iteration
	Fold	Friction force at previous iteration
	dF	Friction force change between last two iterations
	lStick	Stick indicator
	lInit	Initialization flag
[in]	dT	Time increment size
[in]	Fmax	The maximum friction force
[in]	Fext	Force that should match friction force on stick
[in]	Ftol	Zero tolerance for friction forces
[in]	X0	Position at start of current time step
[in]	Xn	Current position
[in]	Vn	Current velocity

See frictiontypemodule::frictiontype::linit for the interpretation of the initialization flag lInit.

Author: Karl Erik Thoresen

Date: 11 Mar 1998

Author: Knut Morten Okstad (F90 version)

Date: 09 Jan 2001

Author: Knut Morten Okstad (completely rewritten)

Date: 22 Aug 2002

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◆ findjointforceinfriction()

subroutine frictionroutinesmodule::findjointforceinfriction	(	type(masterslavejointtype), intent(inout)	joint,
		type(samtype), intent(in)	sam,
		real(dp), dimension(:), intent(in)	RF,
		real(dp), dimension(:), intent(in)	Q,
		real(dp), dimension(:), intent(in)	Fs,
		real(dp), dimension(:), intent(in), optional	Fd,
		real(dp), dimension(:), intent(in), optional	Fi
	)

Computes the total applied force in a joint DOF with friction.

Parameters

	joint	The joint to check for friction forces.
[in]	sam	Data for managing system matrix assembly
[in]	RF	Reaction force container
[in]	Q	External force system vector
[in]	Fs	Stiffness force system vector
[in]	Fd	Damping force system vector
[in]	Fi	Inertia force system vector

The total applies force is equal to the sum of all force contributions to the friction DOF, except for the friction force itself.

Author: Knut Morten Okstad

Date: 17 Sep 2007

◆ findmaxfrictionforce()

subroutine frictionroutinesmodule::findmaxfrictionforce	(	real(dp), intent(out)	Fmax,
		real(dp), intent(in)	Fequ,
		real(dp), intent(in)	Fext,
		real(dp), intent(in)	Vel,
		integer, intent(inout)	StickSlip,
		real(dp), intent(in)	F0,
		real(dp), intent(in)	Coulomb,
		real(dp), intent(in)	Stribeck,
		real(dp), intent(in)	Vc
	)

Calculates the maximum friction force.

Parameters

[out]	Fmax	The maximum friction force
[in]	Fequ	Equivalent normal force that creates the friction
[in]	Fext	Force that should match friction force on stick
[in]	Vel	Current velocity in the friction DOF
[in]	StickSlip	Stick/slip indicator
[in]	F0	Prestress load
[in]	Coulomb	Coulomb friction coefficient
[in]	Stribeck	Magnitude of the Stribeck effect
[in]	Vc	Critical speed of the Stribeck effect

Author: Karl Erik Thoresen

Date: 11 Mar 1998

Author: Knut Morten Okstad (F90 version)

Date: 09 Jan 2001

Author: Knut Morten Okstad (completely rewritten)

Date: 22 Aug 2002

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◆ updatefriction()

subroutine frictionroutinesmodule::updatefriction	(	integer, intent(inout)	ierr,
		real(dp), intent(in)	dt,
		real(dp), intent(in)	deltaT,
		type(frictiontype), intent(inout)	friction,
		integer, intent(in), optional	jDof,
		type(masterslavejointtype), intent(in), optional	joint,
		type(contactelementtype), intent(in), optional	cElem
	)

Updates friction forces in the given joint or contact element.

Parameters

	ierr	Error Flag
[in]	dt	Time increment size
[in]	deltaT	Time increment for finite difference velocity calculation
	friction	The friction object to update forces for
[in]	jDof	Local joint DOF of the friction
[in]	joint	The joint owning this friction
[in]	cElem	The contact element owning this friction

Author: Hans Petter Hildre

Date: 20 Dec 1990

Author: Karl E. Thoresen / Bjorn Haugen (to F90)

Date: around 2000

Author: Knut Morten Okstad (completely rewritten)

Date: 28 Aug 2002

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◆ updatefrictions()

subroutine, public frictionroutinesmodule::updatefrictions	(	type(masterslavejointtype), dimension(:), intent(inout)	joints,
		type(contactelementtype), dimension(:), intent(inout)	cElems,
		real(dp), intent(in)	dt,
		integer, intent(in)	iter,
		logical, intent(in)	useRealVel,
		integer, intent(inout)	ierr
	)

Updates the friction forces in all joints and contact elements.

Parameters

	joints	Array of all joints in the model
	cElems	Array of all contact elements in the model
[in]	dt	Time increment size
[in]	iter	Iteration counter
[in]	useRealVel	If .true., the actual velocity is used
	ierr	Error Flag

Author: Knut Morten Okstad

Date: 30 May 2008

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◆ updatemultidoffriction()

subroutine frictionroutinesmodule::updatemultidoffriction	(	integer, intent(inout)	ierr,
		real(dp), intent(in)	dt,
		real(dp), intent(in)	deltaT,
		type(frictiontype), intent(inout)	friction,
		type(masterslavejointtype), intent(inout)	joint
	)

Updates multidof friction forces in the given joint.

Parameters

	ierr	Error Flag
[in]	dt	Time increment size
[in]	deltaT	Time increment for finite difference velocity calculation
	friction	The friction object to update forces for
[in]	joint	The joint owning this friction

Author: Bjorn Haugen

Date: 25 Apr 2003

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Data Types

Functions/Subroutines

Detailed Description

Function/Subroutine Documentation

◆ addinfrictionforces()

◆ findcontactelmforceinfriction()

◆ findfrictionforce()

◆ findjointforceinfriction()

◆ findmaxfrictionforce()

◆ updatefriction()

◆ updatefrictions()

◆ updatemultidoffriction()