Coulomb Friction Law - Revision history

Nairnj: /* Properties */

2026-03-26T18:22:45Z

Properties

← Older revision		Revision as of 18:22, 26 March 2026
Line 23:		Line 23:
	\| coeffStatic \|\| The static coefficient of friction. If this optional static coefficient of friction is changed to a positive number, it must be greater than the dynamic coefficient or friction. \|\| none \|\| -1		\| coeffStatic \|\| The static coefficient of friction. If this optional static coefficient of friction is changed to a positive number, it must be greater than the dynamic coefficient or friction. \|\| none \|\| -1
	\|-		\|-
	\| displacementOnly<br>Dc \|\| These properties implemented some alternative methods for detecting contact. They are ~~not~~ longer implemented. If an old file enters values, the output ~~that~~ that contact law will ~~explained~~ the feature is "no longer used." \|\| none \|\| 0		\| displacementOnly<br>Dc \|\| These properties implemented some alternative methods for detecting contact. They are no longer implemented. If an old file enters values, the output for that contact law will explain the feature is "no longer used." \|\| none \|\| none
	\|}		\|}

Nairnj: /* Properties */

2026-03-26T18:21:16Z

Properties

← Older revision		Revision as of 18:21, 26 March 2026
Line 23:		Line 23:
	\| coeffStatic \|\| The static coefficient of friction. If this optional static coefficient of friction is changed to a positive number, it must be greater than the dynamic coefficient or friction. \|\| none \|\| -1		\| coeffStatic \|\| The static coefficient of friction. If this optional static coefficient of friction is changed to a positive number, it must be greater than the dynamic coefficient or friction. \|\| none \|\| -1
	\|-		\|-
	\| displacementOnly<br>Dc \|\| ~~Set to: 0 to detect~~ contact ~~when COD<0 <i>and</i> stress<0; 1 to detect~~ contact whenever COD<0 regardless of stress; <0 to detect contact when COD<0 <i>and</i> stress<<tt>-displacementOnly</tt> (in [[ConsistentUnits Command#Legacy and Consistent Units\|pressure units]])\|\| none \|\| 0		\| displacementOnly<br>Dc \|\| These properties implemented some alternative methods for detecting contact. They are not longer implemented. If an old file enters values, the output that that contact law will explained the feature is "no longer used." \|\| none \|\| 0
	\|-
	\| Dc \|\| <0 to find separation assuming perfect interfacial contact, ≥0 to use [[Linear Imperfect Interface\|imperfect interface methods]] to find separation. \|\| [[ConsistentUnits Command#Legacy and Consistent Units\|pressure/length units]] \|\| none
	\|}		\|}

Nairnj: /* Properties */

2026-03-26T18:19:27Z

Properties

← Older revision		Revision as of 18:19, 26 March 2026
Line 23:		Line 23:
	\| coeffStatic \|\| The static coefficient of friction. If this optional static coefficient of friction is changed to a positive number, it must be greater than the dynamic coefficient or friction. \|\| none \|\| -1		\| coeffStatic \|\| The static coefficient of friction. If this optional static coefficient of friction is changed to a positive number, it must be greater than the dynamic coefficient or friction. \|\| none \|\| -1
	\|-		\|-
	\| displacementOnly \|\| Set to: 0 to detect contact when COD<0 <i>and</i> stress<0; 1 to detect contact whenever COD<0 regardless of stress; <0 to detect contact when COD<0 <i>and</i> stress<<tt>-displacementOnly</tt> (in [[ConsistentUnits Command#Legacy and Consistent Units\|pressure units]])\|\| none \|\| 0		\| displacementOnly<br>Dc \|\| Set to: 0 to detect contact when COD<0 <i>and</i> stress<0; 1 to detect contact whenever COD<0 regardless of stress; <0 to detect contact when COD<0 <i>and</i> stress<<tt>-displacementOnly</tt> (in [[ConsistentUnits Command#Legacy and Consistent Units\|pressure units]])\|\| none \|\| 0
	\|-		\|-
	\| Dc \|\| <0 to find separation assuming perfect interfacial contact, ≥0 to use [[Linear Imperfect Interface\|imperfect interface methods]] to find separation. \|\| [[ConsistentUnits Command#Legacy and Consistent Units\|pressure/length units]] \|\| none		\| Dc \|\| <0 to find separation assuming perfect interfacial contact, ≥0 to use [[Linear Imperfect Interface\|imperfect interface methods]] to find separation. \|\| [[ConsistentUnits Command#Legacy and Consistent Units\|pressure/length units]] \|\| none

Nairnj: /* Comments on Parameters */

2023-07-21T00:23:31Z

Comments on Parameters

← Older revision		Revision as of 00:23, 21 July 2023
Line 31:		Line 31:

	# The <tt>displacementOnly</tt> Parameter: this parameter should almost always be zero. In simulations that are known to always be in contact, <tt>displacementOnly=1</tt> sometimes helps the simulation results. The <tt>displacementOnly<0</tt> option to require some tensile stress before loss of contact rarely helps. For one thing, it is not clear how to calculate frictional sliding force when interface is in tension. The code treats tensile stress as a frictionless interface, but will enforce sticking in the normal direction.		# The <tt>displacementOnly</tt> Parameter: this parameter should almost always be zero. In simulations that are known to always be in contact, <tt>displacementOnly=1</tt> sometimes helps the simulation results. The <tt>displacementOnly<0</tt> option to require some tensile stress before loss of contact rarely helps. For one thing, it is not clear how to calculate frictional sliding force when interface is in tension. The code treats tensile stress as a frictionless interface, but will enforce sticking in the normal direction.
	# The <tt>Dc</tt> Parameter: Displacement between two surfaces transitions from zero stiffness when separated to infinite stiffness when in contact. The <tt>Dc</tt> parameter changes the stiffness when in contact to be treated like a [[Linear Imperfect Interface]] and uses interface methods to re-evaluate interfacial separation. This parameter can sometimes help, but also can have a very large effect. It use adds another parameter with little guidance for selecting its' value.		# The <tt>Dc</tt> Parameter: Displacement between two surfaces transitions from zero stiffness when separated to infinite stiffness when in contact. The <tt>Dc</tt> parameter changes the stiffness when in contact to be treated like a [[Linear Imperfect Interface]] and uses interface methods to re-evaluate interfacial separation. This parameter can sometimes help, but also can have a very large effect. Its use adds another parameter with little guidance for selecting its' value.

Nairnj: /* Properties */

2021-06-02T23:10:47Z

Properties

← Older revision		Revision as of 23:10, 2 June 2021
Line 25:		Line 25:
	\| displacementOnly \|\| Set to: 0 to detect contact when COD<0 <i>and</i> stress<0; 1 to detect contact whenever COD<0 regardless of stress; <0 to detect contact when COD<0 <i>and</i> stress<<tt>-displacementOnly</tt> (in [[ConsistentUnits Command#Legacy and Consistent Units\|pressure units]])\|\| none \|\| 0		\| displacementOnly \|\| Set to: 0 to detect contact when COD<0 <i>and</i> stress<0; 1 to detect contact whenever COD<0 regardless of stress; <0 to detect contact when COD<0 <i>and</i> stress<<tt>-displacementOnly</tt> (in [[ConsistentUnits Command#Legacy and Consistent Units\|pressure units]])\|\| none \|\| 0
	\|-		\|-
	\| Dc \|\| <0 to find separation assuming perfect ~~interfaciall~~ contact, ≥0 to use [[Linear Imperfect Interface\|imperfect interface methods]] to find separation. \|\| [[ConsistentUnits Command#Legacy and Consistent Units\|pressure/length units]] \|\| none		\| Dc \|\| <0 to find separation assuming perfect interfacial contact, ≥0 to use [[Linear Imperfect Interface\|imperfect interface methods]] to find separation. \|\| [[ConsistentUnits Command#Legacy and Consistent Units\|pressure/length units]] \|\| none
	\|}		\|}

	=== Comments on Parameters ===		=== Comments on Parameters ===

	# The <tt>displacementOnly</tt> Parameter: this parameter should almost always be zero. In simulations that are known to always be in contact, <tt>displacementOnly=1</tt> sometimes helps the simulation results. The <tt>displacementOnly<0</tt> option to require some tensile stress before loss of contact rarely. For on thing, it is not clear how to calculate ~~friction~~ sliding force when interface is in tension. The code treats tensile stress as a frictionless interface, but will enforce sticking in the normal direction.		# The <tt>displacementOnly</tt> Parameter: this parameter should almost always be zero. In simulations that are known to always be in contact, <tt>displacementOnly=1</tt> sometimes helps the simulation results. The <tt>displacementOnly<0</tt> option to require some tensile stress before loss of contact rarely helps. For one thing, it is not clear how to calculate frictional sliding force when interface is in tension. The code treats tensile stress as a frictionless interface, but will enforce sticking in the normal direction.
	# The <tt>Dc</tt> Parameter: Displacement between two surfaces transitions from zero stiffness when separated to infinite stiffness when in contact. The <tt>Dc</tt> parameter changes the stiffness when in contact to be treated like a [[Linear Imperfect Interface]] and uses interface methods to re-evaluate interfacial separation. This parameter can sometimes help, but also can have a very large effect. It use adds another parameter with little guidance for selecting its' value.		# The <tt>Dc</tt> Parameter: Displacement between two surfaces transitions from zero stiffness when separated to infinite stiffness when in contact. The <tt>Dc</tt> parameter changes the stiffness when in contact to be treated like a [[Linear Imperfect Interface]] and uses interface methods to re-evaluate interfacial separation. This parameter can sometimes help, but also can have a very large effect. It use adds another parameter with little guidance for selecting its' value.

Nairnj at 20:00, 18 September 2020

2020-09-18T20:00:01Z

← Older revision		Revision as of 20:00, 18 September 2020
Line 23:		Line 23:
	\| coeffStatic \|\| The static coefficient of friction. If this optional static coefficient of friction is changed to a positive number, it must be greater than the dynamic coefficient or friction. \|\| none \|\| -1		\| coeffStatic \|\| The static coefficient of friction. If this optional static coefficient of friction is changed to a positive number, it must be greater than the dynamic coefficient or friction. \|\| none \|\| -1
	\|-		\|-
	\| displacementOnly \|\| 0 ~~for~~ contact when COD<0 and stress<0, 1 ~~for~~ contact whenever COD<0, <0 ~~for~~ contact when COD<0 and stress<<tt>-displacementOnly</tt> (in [[ConsistentUnits Command#Legacy and Consistent Units\|pressure units]])\|\| none \|\| 0		\| displacementOnly \|\| Set to: 0 to detect contact when COD<0 <i>and</i> stress<0; 1 to detect contact whenever COD<0 regardless of stress; <0 to detect contact when COD<0 <i>and</i> stress<<tt>-displacementOnly</tt> (in [[ConsistentUnits Command#Legacy and Consistent Units\|pressure units]])\|\| none \|\| 0
	\|-		\|-
	\| Dc \|\| <0 to find separation assuming perfect interfaciall contact, ≥0 to use [[Linear Imperfect Interface\|imperfect interface methods]] to find separation. \|\| [[ConsistentUnits Command#Legacy and Consistent Units\|pressure/length units]] \|\| none		\| Dc \|\| <0 to find separation assuming perfect interfaciall contact, ≥0 to use [[Linear Imperfect Interface\|imperfect interface methods]] to find separation. \|\| [[ConsistentUnits Command#Legacy and Consistent Units\|pressure/length units]] \|\| none

Nairnj at 19:52, 18 September 2020

2020-09-18T19:52:51Z

← Older revision		Revision as of 19:52, 18 September 2020
Line 23:		Line 23:
	\| coeffStatic \|\| The static coefficient of friction. If this optional static coefficient of friction is changed to a positive number, it must be greater than the dynamic coefficient or friction. \|\| none \|\| -1		\| coeffStatic \|\| The static coefficient of friction. If this optional static coefficient of friction is changed to a positive number, it must be greater than the dynamic coefficient or friction. \|\| none \|\| -1
	\|-		\|-
	\| displacementOnly \|\| 0 for contact when COD<0 and stress<0, 1 for contact whenever COD<0, &~~ltl0~~ for contact when COD<0 and stress<<tt>-displacementOnly</tt> (in [[ConsistentUnits Command#Legacy and Consistent Units\|pressure units]])\|\| none \|\| 0		\| displacementOnly \|\| 0 for contact when COD<0 and stress<0, 1 for contact whenever COD<0, <0 for contact when COD<0 and stress<<tt>-displacementOnly</tt> (in [[ConsistentUnits Command#Legacy and Consistent Units\|pressure units]])\|\| none \|\| 0
	\|-		\|-
	\| Dc \|\| <0 to find separation assuming perfect interfaciall contact, ≥0 to use [[Linear Imperfect Interface\|imperfect interface methods]] to find separation. \|\| [[ConsistentUnits Command#Legacy and Consistent Units\|pressure/length units]] \|\| none		\| Dc \|\| <0 to find separation assuming perfect interfaciall contact, ≥0 to use [[Linear Imperfect Interface\|imperfect interface methods]] to find separation. \|\| [[ConsistentUnits Command#Legacy and Consistent Units\|pressure/length units]] \|\| none

Nairnj: /* Properties */

2019-08-14T18:13:09Z

Properties

← Older revision		Revision as of 18:13, 14 August 2019
Line 25:		Line 25:
	\| displacementOnly \|\| 0 for contact when COD<0 and stress<0, 1 for contact whenever COD<0, &ltl0 for contact when COD<0 and stress<<tt>-displacementOnly</tt> (in [[ConsistentUnits Command#Legacy and Consistent Units\|pressure units]])\|\| none \|\| 0		\| displacementOnly \|\| 0 for contact when COD<0 and stress<0, 1 for contact whenever COD<0, &ltl0 for contact when COD<0 and stress<<tt>-displacementOnly</tt> (in [[ConsistentUnits Command#Legacy and Consistent Units\|pressure units]])\|\| none \|\| 0
	\|-		\|-
	\| Dc \|\| <0 to find separation ~~assume~~ perfect ~~interfacial~~ contact, ≥0 to use [[Linear Imperfect Interface\|imperfect interface methods]] to find separation. \|\| [[ConsistentUnits Command#Legacy and Consistent Units\|pressure/length units]] \|\| none		\| Dc \|\| <0 to find separation assuming perfect interfaciall contact, ≥0 to use [[Linear Imperfect Interface\|imperfect interface methods]] to find separation. \|\| [[ConsistentUnits Command#Legacy and Consistent Units\|pressure/length units]] \|\| none
	\|}		\|}

Nairnj: /* Properties */

2019-08-14T17:59:33Z

Properties

← Older revision		Revision as of 17:59, 14 August 2019
Line 25:		Line 25:
	\| displacementOnly \|\| 0 for contact when COD<0 and stress<0, 1 for contact whenever COD<0, &ltl0 for contact when COD<0 and stress<<tt>-displacementOnly</tt> (in [[ConsistentUnits Command#Legacy and Consistent Units\|pressure units]])\|\| none \|\| 0		\| displacementOnly \|\| 0 for contact when COD<0 and stress<0, 1 for contact whenever COD<0, &ltl0 for contact when COD<0 and stress<<tt>-displacementOnly</tt> (in [[ConsistentUnits Command#Legacy and Consistent Units\|pressure units]])\|\| none \|\| 0
	\|-		\|-
	\| Dc \|\| ~~Imperfect interface parameter for detection of~~ contact ~~in the normal direction. If <tt>Dc</tt> is specified~~, ~~the contact law uses~~ [[Linear Imperfect Interface\|imperfect interface methods]] to find separation~~, otherwise it uses standard contact methods~~. \|\| [[ConsistentUnits Command#Legacy and Consistent Units\|pressure/length units]] \|\| none		\| Dc \|\| <0 to find separation assume perfect interfacial contact, ≥0 to use [[Linear Imperfect Interface\|imperfect interface methods]] to find separation. \|\| [[ConsistentUnits Command#Legacy and Consistent Units\|pressure/length units]] \|\| none
	\|}		\|}

Nairnj: /* Properties */

2019-08-14T17:55:08Z

Properties

← Older revision		Revision as of 17:55, 14 August 2019
Line 25:		Line 25:
	\| displacementOnly \|\| 0 for contact when COD<0 and stress<0, 1 for contact whenever COD<0, &ltl0 for contact when COD<0 and stress<<tt>-displacementOnly</tt> (in [[ConsistentUnits Command#Legacy and Consistent Units\|pressure units]])\|\| none \|\| 0		\| displacementOnly \|\| 0 for contact when COD<0 and stress<0, 1 for contact whenever COD<0, &ltl0 for contact when COD<0 and stress<<tt>-displacementOnly</tt> (in [[ConsistentUnits Command#Legacy and Consistent Units\|pressure units]])\|\| none \|\| 0
	\|-		\|-
	\| Dc \|\| Imperfect interface parameter for detection of contact in the normal direction. If <tt>Dc</tt> is specified, the contact law ~~using~~ imperfect interface methods to find separation, otherwise it uses standard contact methods. \|\| [[ConsistentUnits Command#Legacy and Consistent Units\|pressure/length units]] \|\| none		\| Dc \|\| Imperfect interface parameter for detection of contact in the normal direction. If <tt>Dc</tt> is specified, the contact law uses [[Linear Imperfect Interface\|imperfect interface methods]] to find separation, otherwise it uses standard contact methods. \|\| [[ConsistentUnits Command#Legacy and Consistent Units\|pressure/length units]] \|\| none
	\|}		\|}

Line 31:		Line 31:

	# The <tt>displacementOnly</tt> Parameter: this parameter should almost always be zero. In simulations that are known to always be in contact, <tt>displacementOnly=1</tt> sometimes helps the simulation results. The <tt>displacementOnly<0</tt> option to require some tensile stress before loss of contact rarely. For on thing, it is not clear how to calculate friction sliding force when interface is in tension. The code treats tensile stress as a frictionless interface, but will enforce sticking in the normal direction.		# The <tt>displacementOnly</tt> Parameter: this parameter should almost always be zero. In simulations that are known to always be in contact, <tt>displacementOnly=1</tt> sometimes helps the simulation results. The <tt>displacementOnly<0</tt> option to require some tensile stress before loss of contact rarely. For on thing, it is not clear how to calculate friction sliding force when interface is in tension. The code treats tensile stress as a frictionless interface, but will enforce sticking in the normal direction.
	# The <tt>Dc</tt> Parameter: Displacement between two surfaces transitions from 0 stiffness when separated to infinite stiffness when in contact. The <tt>Dc</tt> parameter changes the stiffness when in contact to be treated like a ~~linear imperfect interface~~ and uses interface methods to re-evaluate interfacial separation. This parameter can sometimes help, but also can have a very large effect. It use adds another parameter with little guidance for selecting ~~that parameter~~.		# The <tt>Dc</tt> Parameter: Displacement between two surfaces transitions from zero stiffness when separated to infinite stiffness when in contact. The <tt>Dc</tt> parameter changes the stiffness when in contact to be treated like a [[Linear Imperfect Interface]] and uses interface methods to re-evaluate interfacial separation. This parameter can sometimes help, but also can have a very large effect. It use adds another parameter with little guidance for selecting its' value.