Crack Settings - Revision history

Nairnj: /* References */

2026-03-28T02:22:49Z

References

← Older revision		Revision as of 02:22, 28 March 2026
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	<ref name="GuoJ">Y. Guo and J. A. Nairn, "Calculation of J-Integral and Stress Intensity Factors using the Material Point Method," <i>Computer Modeling in Engineering & Sciences</i>, <b>6</b>, 295-308 (2004). ([http://www.cof.orst.edu/cof/wse/faculty/Nairn/papers/MPMTwoDJ.pdf See PDF])</ref>		<ref name="GuoJ">Y. Guo and J. A. Nairn, "Calculation of J-Integral and Stress Intensity Factors using the Material Point Method," <i>Computer Modeling in Engineering & Sciences</i>, <b>6</b>, 295-308 (2004). ([http://www.cof.orst.edu/cof/wse/faculty/Nairn/papers/MPMTwoDJ.pdf See PDF])</ref>

	<ref name="icracks">J. A. Nairn and Y. E. Aimene, "Modeling Multiple Crack Propagation in the Material Point Method by J-Integral Methods Accounting for Other Cracks Intersecting the J Contour," ''Engineering Fracture Mechanics'', '''322''', 111143 (2025).</ref>		<ref name="icracks">J. A. Nairn and Y. E. Aimene, "Modeling Multiple Crack Propagation in the Material Point Method by J-Integral Methods Accounting for Other Cracks Intersecting the J Contour," ''Engineering Fracture Mechanics'', '''322''', 111143 (2025). ([http://www.cof.orst.edu/cof/wse/faculty/Nairn/papers/InteractingCracks.pdf See PDF])</ref>

	</references>		</references>

Nairnj: /* J Integral Contour Settings */

2026-03-28T02:21:12Z

J Integral Contour Settings

← Older revision		Revision as of 02:21, 28 March 2026
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	* <tt>(usegrid)</tt> - this optional parameter should be set to 0 or 1 (or false or true in scripted files) to specify that kinetic energy and work energy (used in the J integration) are to be found by extrapolating particle energies (if 0 or false) or by extrapolating particle velocity, stress, and strain and than calculating energies from these grid results (if 1 or true). The default is to use particle energies (o or true). In general, the particle energies are preferred (and hence is the default). In some dynamic problems, particle kinetic energies can develop spurious noise that affect J integral calculations. In such problems, using grid energy might be better. The drawbacks of grid energies, however, are that work energy appears to be less accurate and that calculation of work energy from extrapolated stress and strain is only valid for small strain, linear elastic materials. In brief, the grid energy method should only be used for small-stain, linear elastic problems and then only when dynamic effects appear to be corrupting the results. Otherwise particle energies are preferred.		* <tt>(usegrid)</tt> - this optional parameter should be set to 0 or 1 (or false or true in scripted files) to specify that kinetic energy and work energy (used in the J integration) are to be found by extrapolating particle energies (if 0 or false) or by extrapolating particle velocity, stress, and strain and than calculating energies from these grid results (if 1 or true). The default is to use particle energies (o or true). In general, the particle energies are preferred (and hence is the default). In some dynamic problems, particle kinetic energies can develop spurious noise that affect J integral calculations. In such problems, using grid energy might be better. The drawbacks of grid energies, however, are that work energy appears to be less accurate and that calculation of work energy from extrapolated stress and strain is only valid for small strain, linear elastic materials. In brief, the grid energy method should only be used for small-stain, linear elastic problems and then only when dynamic effects appear to be corrupting the results. Otherwise particle energies are preferred.

	More details on J integral evaluation and on the two J integral terms are given in Guo and Nairn (2006).<ref name="GuoJ"/>		More details on J integral evaluation and on the two J integral terms are given in Guo and Nairn (2006) <ref name="GuoJ"/> and Nairn and Aimene <ref name="icracks"/>. The later explains unique abilities of CRAMP is that calculations work even if the the J countour for one crack intersects another crack.

	=== Crack ContactPosition Command ===		=== Crack ContactPosition Command ===

Nairnj: /* References */

2026-03-28T02:19:47Z

References

← Older revision		Revision as of 02:19, 28 March 2026
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	<references>		<references>
	<ref name="GuoJ">Y. Guo and J. A. Nairn, "Calculation of J-Integral and Stress Intensity Factors using the Material Point Method," <i>Computer Modeling in Engineering & Sciences</i>, <b>6</b>, 295-308 (2004). ([http://www.cof.orst.edu/cof/wse/faculty/Nairn/papers/MPMTwoDJ.pdf See PDF])</ref>		<ref name="GuoJ">Y. Guo and J. A. Nairn, "Calculation of J-Integral and Stress Intensity Factors using the Material Point Method," <i>Computer Modeling in Engineering & Sciences</i>, <b>6</b>, 295-308 (2004). ([http://www.cof.orst.edu/cof/wse/faculty/Nairn/papers/MPMTwoDJ.pdf See PDF])</ref>

			<ref name="icracks">J. A. Nairn and Y. E. Aimene, "Modeling Multiple Crack Propagation in the Material Point Method by J-Integral Methods Accounting for Other Cracks Intersecting the J Contour," ''Engineering Fracture Mechanics'', '''322''', 111143 (2025).</ref>

	</references>		</references>

Nairnj: /* Crack Settings Commands */

2024-04-26T21:56:23Z

Crack Settings Commands

← Older revision		Revision as of 21:56, 26 April 2024
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	AltPropagate (crit),<(dir)>,<(traction)>		AltPropagate (crit),<(dir)>,<(traction)>
	ProagateLength (relLength)		ProagateLength (relLength)
			JContour (size),<(terms)>,<(usegrid)>
	ContactCracks (lawID)		ContactCracks (lawID)
	~~JContour (size),<(terms)>,<(usegrid)>~~
	ContactPositionCracks (cutoff)		ContactPositionCracks (cutoff)
	MovePlane (method),<(prevent)>		MovePlane (method),<(prevent)>
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	<AltPropagate criterion='(critNum)' direction='(dirNum)' traction='(traction)'/>		<AltPropagate criterion='(critNum)' direction='(dirNum)' traction='(traction)'/>
	<PropagateLength>(relLength)</ProagateLength>		<PropagateLength>(relLength)</ProagateLength>
			<JContour size="(size)" terms="(terms)" gridenergy="(usegrid)"/>
	<Friction law='(lawnum)' lawname='(lawID)'/>		<Friction law='(lawnum)' lawname='(lawID)'/>
	~~<JContour size="(size)" terms="(terms)" gridenergy="(usegrid)"/>~~
	<ContactPosition>(cutoff)</ContactPosition>		<ContactPosition>(cutoff)</ContactPosition>
	<MovePlane type='(method)' prevent='(prevent)'/>		<MovePlane type='(method)' prevent='(prevent)'/>

Nairnj at 17:10, 3 November 2023

2023-11-03T17:10:41Z

← Older revision		Revision as of 17:10, 3 November 2023
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	* <tt>(usegrid)</tt> - this optional parameter should be set to 0 or 1 (or false or true in scripted files) to specify that kinetic energy and work energy (used in the J integration) are to be found by extrapolating particle energies (if 0 or false) or by extrapolating particle velocity, stress, and strain and than calculating energies from these grid results (if 1 or true). The default is to use particle energies (o or true). In general, the particle energies are preferred (and hence is the default). In some dynamic problems, particle kinetic energies can develop spurious noise that affect J integral calculations. In such problems, using grid energy might be better. The drawbacks of grid energies, however, are that work energy appears to be less accurate and that calculation of work energy from extrapolated stress and strain is only valid for small strain, linear elastic materials. In brief, the grid energy method should only be used for small-stain, linear elastic problems and then only when dynamic effects appear to be corrupting the results. Otherwise particle energies are preferred.		* <tt>(usegrid)</tt> - this optional parameter should be set to 0 or 1 (or false or true in scripted files) to specify that kinetic energy and work energy (used in the J integration) are to be found by extrapolating particle energies (if 0 or false) or by extrapolating particle velocity, stress, and strain and than calculating energies from these grid results (if 1 or true). The default is to use particle energies (o or true). In general, the particle energies are preferred (and hence is the default). In some dynamic problems, particle kinetic energies can develop spurious noise that affect J integral calculations. In such problems, using grid energy might be better. The drawbacks of grid energies, however, are that work energy appears to be less accurate and that calculation of work energy from extrapolated stress and strain is only valid for small strain, linear elastic materials. In brief, the grid energy method should only be used for small-stain, linear elastic problems and then only when dynamic effects appear to be corrupting the results. Otherwise particle energies are preferred.

	More details on J integral evaluation and on the two J integral terms are given in Guo and Nairn (2006).<ref name="GuoJ"~~>Y. Guo and J. A. Nairn, "Calculation of J-Integral and Stress Intensity Factors using the Material Point Method," <i>Computer Modeling in Engineering & Sciences<~~/~~i>, <b>6</b>, 295-308 (2004). ([http://www.cof.orst.edu/cof/wse/faculty/Nairn/papers/MPMTwoDJ.pdf See PDF])</ref~~>		More details on J integral evaluation and on the two J integral terms are given in Guo and Nairn (2006).<ref name="GuoJ"/>

	=== Crack ContactPosition Command ===		=== Crack ContactPosition Command ===
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	== References ==		== References ==
	<references>		<references>
	<ref name=~~'CRAMP'~~>J. A. Nairn, "Material Point Method ~~Calculations with Explicit Cracks~~," <i>Computer Modeling in Engineering & Sciences</i>, <b>4</b>, ~~649~~-~~664~~ (~~2003~~). ([http://www.cof.orst.edu/cof/wse/faculty/Nairn/papers/~~MPMCracks~~.pdf See PDF])</ref>		<ref name="GuoJ">Y. Guo and J. A. Nairn, "Calculation of J-Integral and Stress Intensity Factors using the Material Point Method," <i>Computer Modeling in Engineering & Sciences</i>, <b>6</b>, 295-308 (2004). ([http://www.cof.orst.edu/cof/wse/faculty/Nairn/papers/MPMTwoDJ.pdf See PDF])</ref>

	</references>		</references>

Nairnj at 17:08, 3 November 2023

2023-11-03T17:08:58Z

← Older revision		Revision as of 17:08, 3 November 2023
Line 77:		Line 77:

	== References ==		== References ==
	<references/>		<references>
			<ref name='CRAMP'>J. A. Nairn, "Material Point Method Calculations with Explicit Cracks," <i>Computer Modeling in Engineering & Sciences</i>, <b>4</b>, 649-664 (2003). ([http://www.cof.orst.edu/cof/wse/faculty/Nairn/papers/MPMCracks.pdf See PDF])</ref>

			</references>

Nairnj: /* Crack ContactPosition Command */

2019-08-14T19:06:07Z

Crack ContactPosition Command

← Older revision		Revision as of 19:06, 14 August 2019
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	=== Crack ContactPosition Command ===		=== Crack ContactPosition Command ===

	This command influences the way ~~crack~~ detect contact between the crack surfaces. Its function and use are described [[Detecting Contact#Explicit Crack Contact Detection\|here]].		This command influences the way cracks detect contact between the crack surfaces. Its function and use are described [[Detecting Contact#Explicit Crack Contact Detection\|here]].

	=== Crack Plane Updating ===		=== Crack Plane Updating ===

Nairnj: /* Crack Settings Commands */

2019-08-14T19:05:17Z

Crack Settings Commands

← Older revision		Revision as of 19:05, 14 August 2019
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	ContactCracks (lawID)		ContactCracks (lawID)
	JContour (size),<(terms)>,<(usegrid)>		JContour (size),<(terms)>,<(usegrid)>
	~~ContactPosition~~ (cutoff)		ContactPositionCracks (cutoff)
	MovePlane (method),<(prevent)>		MovePlane (method),<(prevent)>

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	* [[#Crack Contact Properties\|<tt>ContactCracks</tt> and <tt><Friction></tt>]] - set default crack surface contact mechanics		* [[#Crack Contact Properties\|<tt>ContactCracks</tt> and <tt><Friction></tt>]] - set default crack surface contact mechanics
	* [[#J Integral Contour Settings\|<tt>JContour</tt>]] - customize J integral calculation		* [[#J Integral Contour Settings\|<tt>JContour</tt>]] - customize J integral calculation
	* [[#Crack ContactPosition Command\|<tt>~~ContactPosition~~</tt>]] - change method used to detect crack surface contact		* [[#Crack ContactPosition Command\|<tt>ContactPositionCracks</tt>]] - change method used to detect crack surface contact
	* [[#Crack Plane Updating\|<tt>MovePlane</tt>]] - set method to update crack plane position		* [[#Crack Plane Updating\|<tt>MovePlane</tt>]] - set method to update crack plane position

Nairnj: /* J Integral Contour Settings */

2019-04-18T03:13:43Z

J Integral Contour Settings

← Older revision		Revision as of 03:13, 18 April 2019
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	* <tt>(size)</tt> - the J integral is evaluated on a rectangular contour center on the grid node closet to the crack tip (see blue line in the figure). The <tt>(size)</tt> setting is the semi-length for the sides of the rectangle. The default value is 2 (as shown in the figure).		* <tt>(size)</tt> - the J integral is evaluated on a rectangular contour center on the grid node closet to the crack tip (see blue line in the figure). The <tt>(size)</tt> setting is the semi-length for the sides of the rectangle. The default value is 2 (as shown in the figure).
	* <tt>(terms)</tt> - this optional parameter should be set to 1 or 2 to specify if the J Integral should be a simple contour (1) or include an area integral inside the contour (2). The area integral corrects for dynamic effects and for axisymmetric stress states making the calculation path independent even in dynamic problems, but is slower. A contour alone (1) might be enough if the size of the contour is small (<i>e.g.</i>, <tt>(size)</tt>=2) and the loading is slow, but both contour and area might be essential as the problem becomes more dynamic or as the size of the contour grows. The default is 1, but for axisymmetric calculations, the area integral is needed even for static problems, and therefore the default changes to 2 terms.		* <tt>(terms)</tt> - this optional parameter should be set to 1 or 2 to specify if the J Integral should be a simple contour (1) or include an area integral inside the contour (2). The area integral corrects for dynamic effects and for axisymmetric stress states making the calculation path independent even in dynamic problems, but is slower. A contour alone (1) might be enough if the size of the contour is small (<i>e.g.</i>, <tt>(size)</tt>=2) and the loading is slow, but both contour and area might be essential as the problem becomes more dynamic or as the size of the contour grows. The default is 1, but for axisymmetric calculations, the area integral is needed even for static problems, and therefore the default changes to 2 terms.
	* <tt>(usegrid)</tt> - this optional parameter should be set to 0 or 1 to specify that kinetic energy and work energy (used in the J integration) are to be found by extrapolating particle energies (if 0) or by extrapolating particle velocity, stress, and strain and than calculating energies from these grid results (if 1). The default is to use particle energies or ~~to be 0~~. In general, the particle energies are preferred (and hence is the default). In some dynamic problems, particle kinetic energies can develop spurious noise that affect J integral calculations. In such problems, using grid energy might be better. The drawbacks of grid energies, however, are that work energy appears to be less accurate and that calculation of work energy from extrapolated stress and strain is only valid for small strain, linear elastic materials. In brief, the grid energy method should only be used for small-stain, linear elastic problems and then only when dynamic effects appear to be corrupting the results. Otherwise particle energies are preferred.		* <tt>(usegrid)</tt> - this optional parameter should be set to 0 or 1 (or false or true in scripted files) to specify that kinetic energy and work energy (used in the J integration) are to be found by extrapolating particle energies (if 0 or false) or by extrapolating particle velocity, stress, and strain and than calculating energies from these grid results (if 1 or true). The default is to use particle energies (o or true). In general, the particle energies are preferred (and hence is the default). In some dynamic problems, particle kinetic energies can develop spurious noise that affect J integral calculations. In such problems, using grid energy might be better. The drawbacks of grid energies, however, are that work energy appears to be less accurate and that calculation of work energy from extrapolated stress and strain is only valid for small strain, linear elastic materials. In brief, the grid energy method should only be used for small-stain, linear elastic problems and then only when dynamic effects appear to be corrupting the results. Otherwise particle energies are preferred.

	More details on J integral evaluation and on the two J integral terms are given in Guo and Nairn (2006).<ref name="GuoJ">Y. Guo and J. A. Nairn, "Calculation of J-Integral and Stress Intensity Factors using the Material Point Method," <i>Computer Modeling in Engineering & Sciences</i>, <b>6</b>, 295-308 (2004). ([http://www.cof.orst.edu/cof/wse/faculty/Nairn/papers/MPMTwoDJ.pdf See PDF])</ref>		More details on J integral evaluation and on the two J integral terms are given in Guo and Nairn (2006).<ref name="GuoJ">Y. Guo and J. A. Nairn, "Calculation of J-Integral and Stress Intensity Factors using the Material Point Method," <i>Computer Modeling in Engineering & Sciences</i>, <b>6</b>, 295-308 (2004). ([http://www.cof.orst.edu/cof/wse/faculty/Nairn/papers/MPMTwoDJ.pdf See PDF])</ref>

Nairnj: /* J Integral Contour Settings */

2017-03-22T18:07:24Z

J Integral Contour Settings

← Older revision		Revision as of 18:07, 22 March 2017
Line 49:		Line 49:
	* <tt>(size)</tt> - the J integral is evaluated on a rectangular contour center on the grid node closet to the crack tip (see blue line in the figure). The <tt>(size)</tt> setting is the semi-length for the sides of the rectangle. The default value is 2 (as shown in the figure).		* <tt>(size)</tt> - the J integral is evaluated on a rectangular contour center on the grid node closet to the crack tip (see blue line in the figure). The <tt>(size)</tt> setting is the semi-length for the sides of the rectangle. The default value is 2 (as shown in the figure).
	* <tt>(terms)</tt> - this optional parameter should be set to 1 or 2 to specify if the J Integral should be a simple contour (1) or include an area integral inside the contour (2). The area integral corrects for dynamic effects and for axisymmetric stress states making the calculation path independent even in dynamic problems, but is slower. A contour alone (1) might be enough if the size of the contour is small (<i>e.g.</i>, <tt>(size)</tt>=2) and the loading is slow, but both contour and area might be essential as the problem becomes more dynamic or as the size of the contour grows. The default is 1, but for axisymmetric calculations, the area integral is needed even for static problems, and therefore the default changes to 2 terms.		* <tt>(terms)</tt> - this optional parameter should be set to 1 or 2 to specify if the J Integral should be a simple contour (1) or include an area integral inside the contour (2). The area integral corrects for dynamic effects and for axisymmetric stress states making the calculation path independent even in dynamic problems, but is slower. A contour alone (1) might be enough if the size of the contour is small (<i>e.g.</i>, <tt>(size)</tt>=2) and the loading is slow, but both contour and area might be essential as the problem becomes more dynamic or as the size of the contour grows. The default is 1, but for axisymmetric calculations, the area integral is needed even for static problems, and therefore the default changes to 2 terms.
	* <tt>(usegrid)</tt> - this optional parameter should be set to 0 or 1 to specify that kinetic energy and work energy (used in the J integration) are to be found by extrapolating particle energies (if 0) or by extrapolating particle velocity, stress, and strain and than calculating energies from these grid results (if 1). The default is to use particle energies or to be 0. In general, ~~grid~~ energies are ~~less likely to have~~ spurious noise ~~near crack tips and are preferred~~. ~~A drawback~~ of grid energies, however, is that ~~they must assume linear elastic~~ stress and strain~~. When calculating J integral with non-~~linear elastic ~~(or plastic)~~ materials, ~~a setting of 1~~ should ~~not~~ be used.		* <tt>(usegrid)</tt> - this optional parameter should be set to 0 or 1 to specify that kinetic energy and work energy (used in the J integration) are to be found by extrapolating particle energies (if 0) or by extrapolating particle velocity, stress, and strain and than calculating energies from these grid results (if 1). The default is to use particle energies or to be 0. In general, the particle energies are preferred (and hence is the default). In some dynamic problems, particle kinetic energies can develop spurious noise that affect J integral calculations. In such problems, using grid energy might be better. The drawbacks of grid energies, however, are that work energy appears to be less accurate and that calculation of work energy from extrapolated stress and strain is only valid for small strain, linear elastic materials. In brief, the grid energy method should only be used for small-stain, linear elastic problems and then only when dynamic effects appear to be corrupting the results. Otherwise particle energies are preferred.

	More details on J integral evaluation and on the two J integral terms are given in Guo and Nairn (2006).<ref name="GuoJ">Y. Guo and J. A. Nairn, "Calculation of J-Integral and Stress Intensity Factors using the Material Point Method," <i>Computer Modeling in Engineering & Sciences</i>, <b>6</b>, 295-308 (2004). ([http://www.cof.orst.edu/cof/wse/faculty/Nairn/papers/MPMTwoDJ.pdf See PDF])</ref>		More details on J integral evaluation and on the two J integral terms are given in Guo and Nairn (2006).<ref name="GuoJ">Y. Guo and J. A. Nairn, "Calculation of J-Integral and Stress Intensity Factors using the Material Point Method," <i>Computer Modeling in Engineering & Sciences</i>, <b>6</b>, 295-308 (2004). ([http://www.cof.orst.edu/cof/wse/faculty/Nairn/papers/MPMTwoDJ.pdf See PDF])</ref>