Boundary Condition Styles - Revision history

Nairnj: /* Setting Styles */

2020-02-18T19:30:58Z

Setting Styles

← Older revision		Revision as of 19:30, 18 February 2020
Line 25:		Line 25:
	<li style="padding-top: 9px;"><tt>silent</tt> (or 5) - to apply an "absorbing" boundary condition as explained [[#Silent Boundary Conditions\|below]]. These are only allowed for [[Setting Forces and Fluxes\|load, heat flux, and concentration flux conditions]].		<li style="padding-top: 9px;"><tt>silent</tt> (or 5) - to apply an "absorbing" boundary condition as explained [[#Silent Boundary Conditions\|below]]. These are only allowed for [[Setting Forces and Fluxes\|load, heat flux, and concentration flux conditions]].

	<li style="padding-top: 9px;"><tt>function</tt> (or 6) - the applied boundary condition is determined by a [[User Defined Functions\|user-defined function]] of time (<tt>t</tt> in [[ConsistentUnits Command#Legacy and Consistent Units\|alt time units]]), nodal point position, and/or of current clockwise particle rotation angle (2D only). The function should evaluate to the desired value in the standard units for the type of boundary condition. If <tt>(time)</tt> is supplied, the condition starts at time <tt>(time)</tt> (in [[ConsistentUnits Command#Legacy and Consistent Units\|alt time units]]) and the function is evaluated at <tt>[t-(time)]</tt> (instead of at <tt>t</tt>).		<li style="padding-top: 9px;"><tt>function</tt> (or 6) - the applied boundary condition is determined by a [[User Defined Functions\|user-defined function]] of time (<tt>t</tt> in [[ConsistentUnits Command#Legacy and Consistent Units\|alt time units]]), position (which is nodal point position for grid conditions or particle position for particle conditions), and/or of current clockwise particle rotation angle (2D only). The function should evaluate to the desired value in the standard units for the type of boundary condition. If <tt>(time)</tt> is supplied, the condition starts at time <tt>(time)</tt> (in [[ConsistentUnits Command#Legacy and Consistent Units\|alt time units]]) and the function is evaluated at <tt>[t-(time)]</tt> (instead of at <tt>t</tt>).
	</ul>		</ul>

Nairnj: /* Notes */

2017-09-20T18:48:22Z

Notes

← Older revision		Revision as of 18:48, 20 September 2017
Line 46:		Line 46:
	# When applying multiple velocity conditions on the same node, the combinations must either be in the same direction or in orthogonal directions. For example, you can apply any combination of velocities [[Setting Velocity and Transport Values#Velocity Conditions\|along analysis axes (x, y, or z)]].		# When applying multiple velocity conditions on the same node, the combinations must either be in the same direction or in orthogonal directions. For example, you can apply any combination of velocities [[Setting Velocity and Transport Values#Velocity Conditions\|along analysis axes (x, y, or z)]].
	# When using [[Setting Velocity and Transport Values#Skewed Velocity Conditions\|skewed velocity conditions]], the typical problem will use only a single skewed direction on a node. You can use any number of conditions in that single direction. You should not mix [[Setting Velocity and Transport Values#Skewed Velocity Conditions\|skewed velocity conditions]] with [[Setting Velocity and Transport Values#Velocity Conditions\|velocity conditions]] along one of the skew axes. For example, you should not apply some conditions in the x direction and others in the skewed x-y or x-z direction, because these two directions are not orthogonal. In principle orthogonal skewed directions could be used, but such problems can normally be recast to get the same fixed velocity by fixing the two axes in the skew plane instead.		# When using [[Setting Velocity and Transport Values#Skewed Velocity Conditions\|skewed velocity conditions]], the typical problem will use only a single skewed direction on a node. You can use any number of conditions in that single direction. You should not mix [[Setting Velocity and Transport Values#Skewed Velocity Conditions\|skewed velocity conditions]] with [[Setting Velocity and Transport Values#Velocity Conditions\|velocity conditions]] along one of the skew axes. For example, you should not apply some conditions in the x direction and others in the skewed x-y or x-z direction, because these two directions are not orthogonal. In principle orthogonal skewed directions could be used, but such problems can normally be recast to get the same fixed velocity by fixing the two axes in the skew plane instead.
	# When applying multiple concentration conditions on the same node, the net result must add up to a valid concentration potential between 0 and 1.		# When applying multiple concentration conditions on the same node, the net result must add up to a valid concentration potential between 0 and 1. The use is responsible for these limits. The code will limit particle values to be between 0 and 1 even if a boundary condition is out of this range.

	== References ==		== References ==
	<references/>		<references/>

Nairnj: /* Notes */

2017-09-20T18:47:44Z

Notes

← Older revision		Revision as of 18:47, 20 September 2017
Line 46:		Line 46:
	# When applying multiple velocity conditions on the same node, the combinations must either be in the same direction or in orthogonal directions. For example, you can apply any combination of velocities [[Setting Velocity and Transport Values#Velocity Conditions\|along analysis axes (x, y, or z)]].		# When applying multiple velocity conditions on the same node, the combinations must either be in the same direction or in orthogonal directions. For example, you can apply any combination of velocities [[Setting Velocity and Transport Values#Velocity Conditions\|along analysis axes (x, y, or z)]].
	# When using [[Setting Velocity and Transport Values#Skewed Velocity Conditions\|skewed velocity conditions]], the typical problem will use only a single skewed direction on a node. You can use any number of conditions in that single direction. You should not mix [[Setting Velocity and Transport Values#Skewed Velocity Conditions\|skewed velocity conditions]] with [[Setting Velocity and Transport Values#Velocity Conditions\|velocity conditions]] along one of the skew axes. For example, you should not apply some conditions in the x direction and others in the skewed x-y or x-z direction, because these two directions are not orthogonal. In principle orthogonal skewed directions could be used, but such problems can normally be recast to get the same fixed velocity by fixing the two axes in the skew plane instead.		# When using [[Setting Velocity and Transport Values#Skewed Velocity Conditions\|skewed velocity conditions]], the typical problem will use only a single skewed direction on a node. You can use any number of conditions in that single direction. You should not mix [[Setting Velocity and Transport Values#Skewed Velocity Conditions\|skewed velocity conditions]] with [[Setting Velocity and Transport Values#Velocity Conditions\|velocity conditions]] along one of the skew axes. For example, you should not apply some conditions in the x direction and others in the skewed x-y or x-z direction, because these two directions are not orthogonal. In principle orthogonal skewed directions could be used, but such problems can normally be recast to get the same fixed velocity by fixing the two axes in the skew plane instead.
			# When applying multiple concentration conditions on the same node, the net result must add up to a valid concentration potential between 0 and 1.

	== References ==		== References ==
	<references/>		<references/>

Nairnj: /* Setting Styles */

2017-09-20T18:46:48Z

Setting Styles

← Older revision		Revision as of 18:46, 20 September 2017
Line 28:		Line 28:
	</ul>		</ul>

	To get any time-dependence for a boundary condition, you can combine more than one conditions in the same direction and the resulting condition will be a superposition of the applied conditions. See [[#Notes\|below]] for some special considerations when ~~apply velocity conditions~~.		To get any time-dependence for a boundary condition, you can combine more than one conditions in the same direction and the resulting condition will be a superposition of the applied conditions. See [[#Notes\|below]] for some special considerations when applying multiple boundary condition on the same node.

	== Silent Boundary Conditions ==		== Silent Boundary Conditions ==

Nairnj at 18:42, 20 September 2017

2017-09-20T18:42:56Z

← Older revision		Revision as of 18:42, 20 September 2017
Line 44:		Line 44:
	== Notes ==		== Notes ==

	# When applying multiple velocity conditions on the same node, the combinations must either be in the same direction or in orthogonal directions. For example, you can apply any combination of velocities [[Setting Velocity~~, Temperature,~~ and ~~Concentration~~#Velocity Conditions\|along analysis axes (x, y, or z)]].		# When applying multiple velocity conditions on the same node, the combinations must either be in the same direction or in orthogonal directions. For example, you can apply any combination of velocities [[Setting Velocity and Transport Values#Velocity Conditions\|along analysis axes (x, y, or z)]].
	# When using [[Setting Velocity~~, Temperature,~~ and ~~Concentration~~#Skewed Velocity Conditions\|skewed velocity conditions]], the typical problem will use only a single skewed direction on a node. You can use any number of conditions in that single direction. You should not mix [[Setting Velocity~~, Temperature,~~ and ~~Concentration~~#Skewed Velocity Conditions\|skewed velocity conditions]] with [[Setting Velocity~~, Temperature,~~ and ~~Concentration~~#Velocity Conditions\|velocity conditions]] along one of the skew axes. For example, you should not apply some conditions in the x direction and others in the skewed x-y or x-z direction, because these two directions are not orthogonal. In principle orthogonal skewed directions could be used, but such problems can normally be recast to get the same fixed velocity by fixing the two axes in the skew plane instead.		# When using [[Setting Velocity and Transport Values#Skewed Velocity Conditions\|skewed velocity conditions]], the typical problem will use only a single skewed direction on a node. You can use any number of conditions in that single direction. You should not mix [[Setting Velocity and Transport Values#Skewed Velocity Conditions\|skewed velocity conditions]] with [[Setting Velocity and Transport Values#Velocity Conditions\|velocity conditions]] along one of the skew axes. For example, you should not apply some conditions in the x direction and others in the skewed x-y or x-z direction, because these two directions are not orthogonal. In principle orthogonal skewed directions could be used, but such problems can normally be recast to get the same fixed velocity by fixing the two axes in the skew plane instead.

	== References ==		== References ==
	<references/>		<references/>

Nairnj: /* Setting Styles */

2016-09-20T16:33:39Z

Setting Styles

← Older revision		Revision as of 16:33, 20 September 2016
Line 25:		Line 25:
	<li style="padding-top: 9px;"><tt>silent</tt> (or 5) - to apply an "absorbing" boundary condition as explained [[#Silent Boundary Conditions\|below]]. These are only allowed for [[Setting Forces and Fluxes\|load, heat flux, and concentration flux conditions]].		<li style="padding-top: 9px;"><tt>silent</tt> (or 5) - to apply an "absorbing" boundary condition as explained [[#Silent Boundary Conditions\|below]]. These are only allowed for [[Setting Forces and Fluxes\|load, heat flux, and concentration flux conditions]].

	<li style="padding-top: 9px;"><tt>function</tt> (or 6) - the applied boundary condition is determined by a [[User Defined Functions\|user-defined function]] of time (<tt>t</tt> in [[ConsistentUnits Command#Legacy and Consistent Units\|alt time units]]), nodal point position, and/or of current clockwise particle rotation angle (2D only). The function should evaluate to the desired value in the standard units for the type of boundary condition. If <tt>(time)</tt> is supplied, the condition starts at time <tt>(time)</tt> (in [[ConsistentUnits Command#Legacy and Consistent Units\|alt time units]]) and the function is evaluated at <tt>[t-(time)]</tt> (instead of at <tt>t</tt>)~~[[ConsistentUnits Command#Legacy and Consistent Units\|alt time units]]~~		<li style="padding-top: 9px;"><tt>function</tt> (or 6) - the applied boundary condition is determined by a [[User Defined Functions\|user-defined function]] of time (<tt>t</tt> in [[ConsistentUnits Command#Legacy and Consistent Units\|alt time units]]), nodal point position, and/or of current clockwise particle rotation angle (2D only). The function should evaluate to the desired value in the standard units for the type of boundary condition. If <tt>(time)</tt> is supplied, the condition starts at time <tt>(time)</tt> (in [[ConsistentUnits Command#Legacy and Consistent Units\|alt time units]]) and the function is evaluated at <tt>[t-(time)]</tt> (instead of at <tt>t</tt>).
	</ul>		</ul>

Nairnj at 22:42, 2 June 2015

2015-06-02T22:42:26Z

← Older revision		Revision as of 22:42, 2 June 2015
Line 16:		Line 16:

	<math>BC = ({\rm value})\sin\bigl[({\rm time})*t\bigr]</math>		<math>BC = ({\rm value})\sin\bigl[({\rm time})*t\bigr]</math>
	<br><br>This condition is applied for all times. The units for <tt>(time)</tt> should change to 1/ms (''i.e.'', it becomes a frequency in radians/ms).		<br><br>This condition is applied for all times. The units for <tt>(time)</tt> should change to [[ConsistentUnits Command#Legacy and Consistent Units\|1/alt time units]] (''i.e.'', it becomes a frequency in [[ConsistentUnits Command#Legacy and Consistent Units\|radians/alt time units]]).

	<li style="padding-top: 9px;"><tt>cosine</tt> (or 4) - the applied boundary condition is<br><br>		<li style="padding-top: 9px;"><tt>cosine</tt> (or 4) - the applied boundary condition is<br><br>

	<math>BC = ({\rm value})\cos\bigl[({\rm time})*t\bigr]</math>		<math>BC = ({\rm value})\cos\bigl[({\rm time})*t\bigr]</math>
	<br><br>This condition is applied for all times. The units for <tt>(time)</tt> should change to 1/ms (''i.e.'', it becomes a frequency in radians/ms).		<br><br>This condition is applied for all times. The units for <tt>(time)</tt> should change to [[ConsistentUnits Command#Legacy and Consistent Units\|1/alt time units]] (''i.e.'', it becomes a frequency in [[ConsistentUnits Command#Legacy and Consistent Units\|radians/alt time units]]).

	<li style="padding-top: 9px;"><tt>silent</tt> (or 5) - to apply an "absorbing" boundary condition as explained [[#Silent Boundary Conditions\|below]]. These are only allowed for [[Setting Forces and Fluxes\|load, heat flux, and concentration flux conditions]].		<li style="padding-top: 9px;"><tt>silent</tt> (or 5) - to apply an "absorbing" boundary condition as explained [[#Silent Boundary Conditions\|below]]. These are only allowed for [[Setting Forces and Fluxes\|load, heat flux, and concentration flux conditions]].

Nairnj at 22:14, 2 June 2015

2015-06-02T22:14:53Z

← Older revision		Revision as of 22:14, 2 June 2015
Line 2:		Line 2:
	== Setting Styles ==		== Setting Styles ==

	The possible [[MPM Input Files#Boundary Conditions\|boundary condition]] styles are defined below. In scripted files, the style can be set by name or number; in <tt>XML</tt> files, the style must be set by number. Unless otherwise specified, the units for <tt>(value)</tt> are the standard units for the current type of boundary condition (''i.e''., [[ConsistentUnits Command#Legacy and Consistent Units\|velocity units]] for velocity, degrees K for temperature, ''etc.'') and the units for <tt>(time)</tt> are ms.		The possible [[MPM Input Files#Boundary Conditions\|boundary condition]] styles are defined below. In scripted files, the style can be set by name or number; in <tt>XML</tt> files, the style must be set by number. Unless otherwise specified, the units for <tt>(value)</tt> are the standard units for the current type of boundary condition (''i.e''., [[ConsistentUnits Command#Legacy and Consistent Units\|velocity units]] for velocity, degrees K for temperature, ''etc.'') and the units for <tt>(time)</tt> are [[ConsistentUnits Command#Legacy and Consistent Units\|alt time units]].

	<ul>		<ul>
Line 11:		Line 11:

	<math>BC = ({\rm value})*(t-({\rm time}))</math>		<math>BC = ({\rm value})*(t-({\rm time}))</math>
	<br><br>where t is the current time (in ms). This condition is applied only for times after <tt>(time)</tt>. The units for <tt>(value)</tt> should change to the standard units for the boundary condition per ms.		<br><br>where t is the current time (in [[ConsistentUnits Command#Legacy and Consistent Units\|alt time units]]). This condition is applied only for times after <tt>(time)</tt>. The units for <tt>(value)</tt> should change to the standard units for the boundary condition per [[ConsistentUnits Command#Legacy and Consistent Units\|alt time units]].

	<li style="padding-top: 9px;"><tt>sine</tt> (or 3) - the applied boundary condition is<br><br>		<li style="padding-top: 9px;"><tt>sine</tt> (or 3) - the applied boundary condition is<br><br>
Line 25:		Line 25:
	<li style="padding-top: 9px;"><tt>silent</tt> (or 5) - to apply an "absorbing" boundary condition as explained [[#Silent Boundary Conditions\|below]]. These are only allowed for [[Setting Forces and Fluxes\|load, heat flux, and concentration flux conditions]].		<li style="padding-top: 9px;"><tt>silent</tt> (or 5) - to apply an "absorbing" boundary condition as explained [[#Silent Boundary Conditions\|below]]. These are only allowed for [[Setting Forces and Fluxes\|load, heat flux, and concentration flux conditions]].

	<li style="padding-top: 9px;"><tt>function</tt> (or 6) - the applied boundary condition is determined by a [[User Defined Functions\|user-defined function]] of time (<tt>t</tt> in ms), nodal point position, and/or of current clockwise particle rotation angle (2D only). The function should evaluate to the desired value in the standard units for the type of boundary condition. If <tt>(time)</tt> is supplied, the condition starts at time <tt>(time)</tt> (in ms) and the function is evaluated at <tt>[t-(time)]</tt> (instead of at <tt>t</tt>)		<li style="padding-top: 9px;"><tt>function</tt> (or 6) - the applied boundary condition is determined by a [[User Defined Functions\|user-defined function]] of time (<tt>t</tt> in [[ConsistentUnits Command#Legacy and Consistent Units\|alt time units]]), nodal point position, and/or of current clockwise particle rotation angle (2D only). The function should evaluate to the desired value in the standard units for the type of boundary condition. If <tt>(time)</tt> is supplied, the condition starts at time <tt>(time)</tt> (in [[ConsistentUnits Command#Legacy and Consistent Units\|alt time units]]) and the function is evaluated at <tt>[t-(time)]</tt> (instead of at <tt>t</tt>)[[ConsistentUnits Command#Legacy and Consistent Units\|alt time units]]

	</ul>		</ul>

Nairnj at 21:45, 2 June 2015

2015-06-02T21:45:36Z

← Older revision		Revision as of 21:45, 2 June 2015
Line 2:		Line 2:
	== Setting Styles ==		== Setting Styles ==

	The possible [[MPM Input Files#Boundary Conditions\|boundary condition]] styles are defined below. In scripted files, the style can be set by name or number; in <tt>XML</tt> files, the style must be set by number. Unless otherwise specified, the units for <tt>(value)</tt> are the standard units for the current type of boundary condition (''i.e''., ~~mm/s~~ for velocity, degrees K for temperature, ''etc.'') and the units for <tt>(time)</tt> are ms.		The possible [[MPM Input Files#Boundary Conditions\|boundary condition]] styles are defined below. In scripted files, the style can be set by name or number; in <tt>XML</tt> files, the style must be set by number. Unless otherwise specified, the units for <tt>(value)</tt> are the standard units for the current type of boundary condition (''i.e''., [[ConsistentUnits Command#Legacy and Consistent Units\|velocity units]] for velocity, degrees K for temperature, ''etc.'') and the units for <tt>(time)</tt> are ms.

	<ul>		<ul>

Nairnj: /* Silent Boundary Conditions */

2015-01-02T21:10:28Z

Silent Boundary Conditions

← Older revision		Revision as of 21:10, 2 January 2015
Line 33:		Line 33:
	== Silent Boundary Conditions ==		== Silent Boundary Conditions ==

	The object of silent boundary conditions is to apply an absorbing edge. The goal is to simulate a small portion of a large object by having stress waves, heat fluxes, and concentration fluxes absorbed by the edges rather the reflect back into the object. Their development in MPM is in a paper by Shen and Chen (2005).<ref>L. Shen and Z. Chen, "A Silent Boundary Scheme with the Material Point Method for Dynamic Analyses," ''Computer Modeling in Engineering & Sciences'', '''7''', 305-320 (2005).</ref> ~~This~~ conditions can be shown to work well in small, idealized simulations. They have been less useful in other simulations.		The object of silent boundary conditions is to apply an absorbing edge. The goal is to simulate a small portion of a large object by having stress waves, heat fluxes, and concentration fluxes absorbed by the edges rather the reflect back into the object. Their development in MPM is in a paper by Shen and Chen (2005).<ref>L. Shen and Z. Chen, "A Silent Boundary Scheme with the Material Point Method for Dynamic Analyses," ''Computer Modeling in Engineering & Sciences'', '''7''', 305-320 (2005).</ref> These conditions can be shown to work well in small, idealized simulations. They have been less useful in other simulations.

	Some considerations about using silent boundary conditions in [[NairnMPM]] are.		Some considerations about using silent boundary conditions in [[NairnMPM]] are.