m_fstr_contact_damping Module Reference

Contact damping module for CONTACTNEAR state. More...

Functions/Subroutines
pure logical function, public	is_damping_enabled (contact)
	Check if damping is enabled for a contact pair. More...
pure real(kind=kreal) function, public	contact_damping_weight (g, gact)
	Compute smoothstep weight w(g) for contact damping. More...
subroutine, public	getdampingstiffness (cstate, surf, alpha, gact, stiff, smoothing_type)
	Compute damping stiffness matrix K_damp = alpha * w(g) * Bn (x) Bn. More...
subroutine, public	getdampingnodalforce (cstate, surf, ndDu, alpha, gact, ctNForce, ctTForce, smoothing_type)
	Compute damping nodal force vector f_damp = alpha * w(g) * (Bn^T * ddu) * Bn. More...

Detailed Description

Contact damping module for CONTACTNEAR state.

Provides smoothstep weight function w(g), and routines to compute damping nodal force and tangent stiffness for NEAR-state slave nodes.

Damping residual: r_damp = alpha * w(g) * (Bn^T * ddu) * Bn Damping stiffness: K_damp = alpha * w(g) * Bn (x) Bn

where g = cstatedistance (frozen during Newton iteration), alpha = DAMP_ALPHA * refStiff, and w(g) is a smoothstep that transitions from 1 at g=0 to 0 at g=gact.

Function/Subroutine Documentation

contact_damping_weight()

pure real(kind=kreal) function, public m_fstr_contact_damping::contact_damping_weight	(	real(kind=kreal), intent(in)	g,
		real(kind=kreal), intent(in)	gact
	)

Compute smoothstep weight w(g) for contact damping.

w(g) = 1 if g <= 0 (penetrating) w(g) = 1 - 3t^2 + 2t^3 if 0 < g < gact (near zone) w(g) = 0 if g >= gact (far away)

where t = g / gact

Parameters

[in]	g	signed distance (+ = gap, - = penetration)
[in]	gact	activation distance (NEAR_DIST)

Definition at line 44 of file fstr_contact_damping.f90.

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getdampingnodalforce()

subroutine, public m_fstr_contact_damping::getdampingnodalforce	(	type(tcontactstate), intent(in)	cstate,
		type(tsurfelement), intent(in)	surf,
		real(kind=kreal), dimension(:), intent(in)	ndDu,
		real(kind=kreal), intent(in)	alpha,
		real(kind=kreal), intent(in)	gact,
		real(kind=kreal), dimension(:), intent(out)	ctNForce,
		real(kind=kreal), dimension(:), intent(out)	ctTForce,
		integer(kind=kint), intent(in), optional	smoothing_type
	)

Compute damping nodal force vector f_damp = alpha * w(g) * (Bn^T * ddu) * Bn.

Same interface pattern as getContactNodalForce_Alag: compute force vector, caller assembles via assemble_contact_force_residual. ctNForce receives the damping force; ctTForce is zeroed.

Parameters

[in]	cstate	contact state (NEAR)
[in]	surf	master surface element
[in]	nddu	nodal displacement increment (ddisp for this contact element)
[in]	alpha	damping coefficient (DAMP_ALPHA * refStiff)
[in]	gact	activation distance (NEAR_DIST)
[out]	ctnforce	damping force vector (normal-like)
[out]	cttforce	tangential force vector (zeroed)

Definition at line 105 of file fstr_contact_damping.f90.

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getdampingstiffness()

subroutine, public m_fstr_contact_damping::getdampingstiffness	(	type(tcontactstate), intent(in)	cstate,
		type(tsurfelement), intent(in)	surf,
		real(kind=kreal), intent(in)	alpha,
		real(kind=kreal), intent(in)	gact,
		real(kind=kreal), dimension(:,:), intent(out)	stiff,
		integer(kind=kint), intent(in), optional	smoothing_type
	)

Compute damping stiffness matrix K_damp = alpha * w(g) * Bn (x) Bn.

Same interface pattern as getContactStiffness_Alag: compute stiffness matrix, caller assembles via hecmw_mat_ass_elem.

Parameters

[in]	cstate	contact state (NEAR)
[in]	surf	master surface element
[in]	alpha	damping coefficient (DAMP_ALPHA * refStiff)
[in]	gact	activation distance (NEAR_DIST)
[out]	stiff	damping stiffness matrix

Definition at line 63 of file fstr_contact_damping.f90.

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is_damping_enabled()

pure logical function, public m_fstr_contact_damping::is_damping_enabled

(

type(tcontact), intent(in)

contact

)

Check if damping is enabled for a contact pair.

Definition at line 32 of file fstr_contact_damping.f90.

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