Analysis Command - Revision history

Nairnj: /* References */

2026-04-10T18:02:59Z

References

← Older revision		Revision as of 18:02, 10 April 2026
Line 57:		Line 57:

	<ref name="FMPM">J. A. Nairn and C. C. Hammerquist, "Material point method simulations using an approximate full mass matrix inverse," <i>Computer Methods in Applied Mechanics and Engineering</i>, <b>377</b>, 113667 (2021). (2021). ([http://www.cof.orst.edu/cof/wse/faculty/Nairn/papers/FMPMPaper.pdf See PDF])</ref>		<ref name="FMPM">J. A. Nairn and C. C. Hammerquist, "Material point method simulations using an approximate full mass matrix inverse," <i>Computer Methods in Applied Mechanics and Engineering</i>, <b>377</b>, 113667 (2021). (2021). ([http://www.cof.orst.edu/cof/wse/faculty/Nairn/papers/FMPMPaper.pdf See PDF])</ref>

			<ref name="FMPMrev">J. A. Nairn, "Improved Implementation of Approximate Full Mass Matrix Inverse Methods into Material Point Method Simulations," <i>arXiv:2604.07307</i> (2026). ([https://arxiv.org/abs/2604.07307 See PDF])</ref>

	<ref name="ASPaper">J.A. Nairn and J.E. Guilkey, "Axisymmetric Form of the Generalized Interpolation Material Point Method,"> <i>Int. J. for Numerical Methods in Engineering</i>, <b>101</b>, 127-147 (2015) ([http://www.cof.orst.edu/cof/wse/faculty/Nairn/papers/AxisymGIMP.pdf See PDF]).</ref>		<ref name="ASPaper">J.A. Nairn and J.E. Guilkey, "Axisymmetric Form of the Generalized Interpolation Material Point Method,"> <i>Int. J. for Numerical Methods in Engineering</i>, <b>101</b>, 127-147 (2015) ([http://www.cof.orst.edu/cof/wse/faculty/Nairn/papers/AxisymGIMP.pdf See PDF]).</ref>

	</references>		</references>

Nairnj: /* Tracking Velocity Gradient */

2026-04-10T18:02:47Z

Tracking Velocity Gradient

← Older revision		Revision as of 18:02, 10 April 2026
Line 39:		Line 39:
	When used in standard FLIP MPM, a revised extrapolation to the grid follows methods first presented by Wallstedt and Guilkey.<ref name="WGVG"/> The method used to track velocity gradients, however is different. The best approach to FLIP analysis with velocity gradient tracking is under evaluation.		When used in standard FLIP MPM, a revised extrapolation to the grid follows methods first presented by Wallstedt and Guilkey.<ref name="WGVG"/> The method used to track velocity gradients, however is different. The best approach to FLIP analysis with velocity gradient tracking is under evaluation.

	Another paper relevant to velocity gradient tracking is the APIC method.<ref name="APIC"/> APIC is equivalent to using the [[PeriodicXPIC Custom Task]] with <tt>FMPMOrder</tt> 1 (''i.e.'', PIC style) every time step combined with with [[MPM Methods and Simulation Timing#Classic MPM Methods\|<tt>Classic</tt> or <tt>B2Spline</tt>]] grid-based shape functions (the APIC paper is not clear which they used, but it was probably <tt>B2Spline</tt>). Like all PIC-style methods, APIC can dissipate much energy in certain problems. Using higher <tt>FMPMOrder</tt> while tracking velocity gradient extends APIC to reduce dissipation using approximate full mass matrix methods.<ref name="FMPM"/> Switching to other available [[MPM Methods and Simulation Timing\|shape function types]] extends APIC to methods that work better with large deformations. These extensions to APIC are under evaulation.		Another paper relevant to velocity gradient tracking is the APIC method.<ref name="APIC"/> APIC is equivalent to using the [[PeriodicXPIC Custom Task]] with <tt>FMPMOrder</tt> 1 (''i.e.'', PIC style) every time step combined with with [[MPM Methods and Simulation Timing#Classic MPM Methods\|<tt>Classic</tt> or <tt>B2Spline</tt>]] grid-based shape functions (the APIC paper is not clear which they used, but it was probably <tt>B2Spline</tt>). Like all PIC-style methods, APIC can dissipate much energy in certain problems. Using higher <tt>FMPMOrder</tt> while tracking velocity gradient extends APIC to reduce dissipation using approximate full mass matrix methods.<ref name="FMPM"/><ref name="FMPMrev"/> Switching to other available [[MPM Methods and Simulation Timing\|shape function types]] extends APIC to methods that work better with large deformations. These extensions to APIC are under evaulation.

	== Notes ==		== Notes ==

Nairnj: /* Notes */

2024-04-26T03:32:05Z

Notes

← Older revision		Revision as of 03:32, 26 April 2024
Line 45:		Line 45:
	* The first three (0,1,2) are for [[FEA Input Files\|FEA calculations only]], while the rest (10,11,12,13) are for [[MPM Input Files\|MPM calculations only]].		* The first three (0,1,2) are for [[FEA Input Files\|FEA calculations only]], while the rest (10,11,12,13) are for [[MPM Input Files\|MPM calculations only]].
	* In axisymmetric analyses, the x, y, z, directions become R, Z, and θ directions. If any commands do not mention use of R and Z, they may still work or you can use x and y to mean the same thing. When visualizing results, most labels are changed to reflect R, Z, and θ coordinates. The implementation of axisymmetric MPM is described in a paper by Nairn and Guilkey.<ref name="ASPaper"/>		* In axisymmetric analyses, the x, y, z, directions become R, Z, and θ directions. If any commands do not mention use of R and Z, they may still work or you can use x and y to mean the same thing. When visualizing results, most labels are changed to reflect R, Z, and θ coordinates. The implementation of axisymmetric MPM is described in a paper by Nairn and Guilkey.<ref name="ASPaper"/>
	* A feature in ~~developed~~ can [[Generalized Plane Stress and Strain\|generalize MPM plane stress or plane strain]] to allow non-zero, out-of-plane strain or stress, respectively. The only way to set out-of-plane stress or strain is to use a [[PropertyRamp Custom Task]].		* A feature in development can [[Generalized Plane Stress and Strain\|generalize MPM plane stress or plane strain]] to allow non-zero, out-of-plane strain or stress, respectively. The only way to set out-of-plane stress or strain is to use a [[PropertyRamp Custom Task]].
	* One (and only one) <tt>Analysis</tt> command is required in every input file and it should be near the beginning, because many other commands depend on whether or not the commands are for FEA or for MPM analysis.		* One (and only one) <tt>Analysis</tt> command is required in every input file and it should be near the beginning, because many other commands depend on whether or not the commands are for FEA or for MPM analysis.

Nairnj: /* Tracking Velocity Gradient */

2024-04-26T02:45:56Z

Tracking Velocity Gradient

← Older revision		Revision as of 02:45, 26 April 2024
Line 39:		Line 39:
	When used in standard FLIP MPM, a revised extrapolation to the grid follows methods first presented by Wallstedt and Guilkey.<ref name="WGVG"/> The method used to track velocity gradients, however is different. The best approach to FLIP analysis with velocity gradient tracking is under evaluation.		When used in standard FLIP MPM, a revised extrapolation to the grid follows methods first presented by Wallstedt and Guilkey.<ref name="WGVG"/> The method used to track velocity gradients, however is different. The best approach to FLIP analysis with velocity gradient tracking is under evaluation.

	Another paper relevant to velocity gradient tracking is the APIC method.<ref name="APIC"/> APIC is equivalent to using the [[PeriodicXPIC Custom Task]] with <tt>FMPMOrder</tt> 1 (''i.e.'', PIC style) every time step combined with with [[MPM Methods and Simulation Timing#Classic MPM Methods\|<tt>Classic</tt> or <tt>B2Spline</tt>]] grid-based shape functions (the APIC paper is not clear which they used, but it was probably <tt>B2Spline</tt>). Like all PIC-style methods, APIC can dissipate much energy in certain problems. Using higher <tt>FMPMOrder</tt> while tracking velocity gradient extends APIC to reduce dissipation using approximate full mass matrix methods.<ref name="FMPM"/> Switching to other available [[MPM Methods and Simulation Timing\|shape function]] extends APIC to methods that work better with large deformations. ~~The~~ extensions to APIC are under evaulation.		Another paper relevant to velocity gradient tracking is the APIC method.<ref name="APIC"/> APIC is equivalent to using the [[PeriodicXPIC Custom Task]] with <tt>FMPMOrder</tt> 1 (''i.e.'', PIC style) every time step combined with with [[MPM Methods and Simulation Timing#Classic MPM Methods\|<tt>Classic</tt> or <tt>B2Spline</tt>]] grid-based shape functions (the APIC paper is not clear which they used, but it was probably <tt>B2Spline</tt>). Like all PIC-style methods, APIC can dissipate much energy in certain problems. Using higher <tt>FMPMOrder</tt> while tracking velocity gradient extends APIC to reduce dissipation using approximate full mass matrix methods.<ref name="FMPM"/> Switching to other available [[MPM Methods and Simulation Timing\|shape function types]] extends APIC to methods that work better with large deformations. These extensions to APIC are under evaulation.

	== Notes ==		== Notes ==

Nairnj: /* Tracking Velocity Gradient */

2024-04-26T02:45:03Z

Tracking Velocity Gradient

← Older revision		Revision as of 02:45, 26 April 2024
Line 39:		Line 39:
	When used in standard FLIP MPM, a revised extrapolation to the grid follows methods first presented by Wallstedt and Guilkey.<ref name="WGVG"/> The method used to track velocity gradients, however is different. The best approach to FLIP analysis with velocity gradient tracking is under evaluation.		When used in standard FLIP MPM, a revised extrapolation to the grid follows methods first presented by Wallstedt and Guilkey.<ref name="WGVG"/> The method used to track velocity gradients, however is different. The best approach to FLIP analysis with velocity gradient tracking is under evaluation.

	Another paper relevant to velocity gradient tracking is the APIC method.<ref name="APIC"/> APIC is equivalent to using the [[PeriodicXPIC Custom Task]] with <tt>FMPMOrder</tt> 1 (''i.e.'', PIC style) every time step combined with with [[MPM Methods and Simulation Timing#Classic MPM Methods\|<tt>Classic</tt> or <tt>B2Spline</tt>]] grid-based shape functions (the APIC paper is not clear which they used, but it was probably <tt>B2Spline</tt>). Like all PIC-style methods, APIC can dissipate much energy in certain problems. Using higher <tt>FMPMOrder</tt> while tracking velocity gradient extends APIC to reduce dissipation using approximate full mass matrix methods.<ref name="FMPM"/> ~~Switch~~ to other available [[MPM Methods and Simulation Timing\|shape function]] extends APIC to methods that work better with large deformations. The extensions to APIC are under evaulation.		Another paper relevant to velocity gradient tracking is the APIC method.<ref name="APIC"/> APIC is equivalent to using the [[PeriodicXPIC Custom Task]] with <tt>FMPMOrder</tt> 1 (''i.e.'', PIC style) every time step combined with with [[MPM Methods and Simulation Timing#Classic MPM Methods\|<tt>Classic</tt> or <tt>B2Spline</tt>]] grid-based shape functions (the APIC paper is not clear which they used, but it was probably <tt>B2Spline</tt>). Like all PIC-style methods, APIC can dissipate much energy in certain problems. Using higher <tt>FMPMOrder</tt> while tracking velocity gradient extends APIC to reduce dissipation using approximate full mass matrix methods.<ref name="FMPM"/> Switching to other available [[MPM Methods and Simulation Timing\|shape function]] extends APIC to methods that work better with large deformations. The extensions to APIC are under evaulation.

	== Notes ==		== Notes ==

Nairnj: /* Tracking Velocity Gradient */

2024-04-26T02:44:44Z

Tracking Velocity Gradient

← Older revision		Revision as of 02:44, 26 April 2024
Line 39:		Line 39:
	When used in standard FLIP MPM, a revised extrapolation to the grid follows methods first presented by Wallstedt and Guilkey.<ref name="WGVG"/> The method used to track velocity gradients, however is different. The best approach to FLIP analysis with velocity gradient tracking is under evaluation.		When used in standard FLIP MPM, a revised extrapolation to the grid follows methods first presented by Wallstedt and Guilkey.<ref name="WGVG"/> The method used to track velocity gradients, however is different. The best approach to FLIP analysis with velocity gradient tracking is under evaluation.

	Another paper relevant to velocity gradient tracking is the APIC method.<ref name="APIC"/> APIC is equivalent to using the [[PeriodicXPIC Custom Task]] with <tt>FMPMOrder</tt> 1 (''i.e.'', PIC style) every time step combined with with [[MPM Methods and Simulation Timing#Classic MPM Methods\|<tt>Classic</tt> or <tt>B2Spline</tt>]] grid-based shape functions (the APIC paper is not clear which they used, but it was probably <tt>B2Spline</tt>). Like all PIC-style ~~method~~, APIC can dissipate much energy in certain problems. Using higher <tt>FMPMOrder</tt> while tracking velocity gradient extends APIC to reduce dissipation using approximate full mass matrix methods.<ref name="FMPM"/> Switch to other available [[MPM Methods and Simulation Timing\|shape function]] extends APIC to methods that work better with large deformations.		Another paper relevant to velocity gradient tracking is the APIC method.<ref name="APIC"/> APIC is equivalent to using the [[PeriodicXPIC Custom Task]] with <tt>FMPMOrder</tt> 1 (''i.e.'', PIC style) every time step combined with with [[MPM Methods and Simulation Timing#Classic MPM Methods\|<tt>Classic</tt> or <tt>B2Spline</tt>]] grid-based shape functions (the APIC paper is not clear which they used, but it was probably <tt>B2Spline</tt>). Like all PIC-style methods, APIC can dissipate much energy in certain problems. Using higher <tt>FMPMOrder</tt> while tracking velocity gradient extends APIC to reduce dissipation using approximate full mass matrix methods.<ref name="FMPM"/> Switch to other available [[MPM Methods and Simulation Timing\|shape function]] extends APIC to methods that work better with large deformations. The extensions to APIC are under evaulation.

	== Notes ==		== Notes ==

Nairnj: /* Tracking Velocity Gradient */

2024-04-26T02:43:43Z

Tracking Velocity Gradient

← Older revision		Revision as of 02:43, 26 April 2024
Line 39:		Line 39:
	When used in standard FLIP MPM, a revised extrapolation to the grid follows methods first presented by Wallstedt and Guilkey.<ref name="WGVG"/> The method used to track velocity gradients, however is different. The best approach to FLIP analysis with velocity gradient tracking is under evaluation.		When used in standard FLIP MPM, a revised extrapolation to the grid follows methods first presented by Wallstedt and Guilkey.<ref name="WGVG"/> The method used to track velocity gradients, however is different. The best approach to FLIP analysis with velocity gradient tracking is under evaluation.

	Another paper relevant to velocity gradient tracking is the APIC method.<ref name="APIC"/>. APIC is equivalent to using the [[PeriodicXPIC Custom Task]] with <tt>FMPMOrder</tt> 1 (''i.e.'', PIC style) every time step combined with with [[MPM Methods and Simulation Timing#Classic MPM Methods\|<tt>Classic</tt> or <tt>B2Spline</tt>]] grid-based shape functions (the APIC paper is not clear which they used, but it was probably <tt>B2Spline</tt>). Like all PIC-style method, APIC can dissipate much energy in certain problems. Using higher <tt>FMPMOrder</tt> while tracking velocity gradient extends APIC to reduce dissipation using approximate full mass matrix methods.<ref name="FMPM"/> Switch to other available [[MPM Methods and Simulation Timing\|shape function]] extends APIC to methods that work better with large deformations.		Another paper relevant to velocity gradient tracking is the APIC method.<ref name="APIC"/> APIC is equivalent to using the [[PeriodicXPIC Custom Task]] with <tt>FMPMOrder</tt> 1 (''i.e.'', PIC style) every time step combined with with [[MPM Methods and Simulation Timing#Classic MPM Methods\|<tt>Classic</tt> or <tt>B2Spline</tt>]] grid-based shape functions (the APIC paper is not clear which they used, but it was probably <tt>B2Spline</tt>). Like all PIC-style method, APIC can dissipate much energy in certain problems. Using higher <tt>FMPMOrder</tt> while tracking velocity gradient extends APIC to reduce dissipation using approximate full mass matrix methods.<ref name="FMPM"/> Switch to other available [[MPM Methods and Simulation Timing\|shape function]] extends APIC to methods that work better with large deformations.

	== Notes ==		== Notes ==

Nairnj: /* Tracking Velocity Gradient */

2024-04-26T02:43:16Z

Tracking Velocity Gradient

← Older revision		Revision as of 02:43, 26 April 2024
Line 39:		Line 39:
	When used in standard FLIP MPM, a revised extrapolation to the grid follows methods first presented by Wallstedt and Guilkey.<ref name="WGVG"/> The method used to track velocity gradients, however is different. The best approach to FLIP analysis with velocity gradient tracking is under evaluation.		When used in standard FLIP MPM, a revised extrapolation to the grid follows methods first presented by Wallstedt and Guilkey.<ref name="WGVG"/> The method used to track velocity gradients, however is different. The best approach to FLIP analysis with velocity gradient tracking is under evaluation.

	Another paper relevant to velocity gradient tracking is the APIC method.<ref name="APIC"/>. APIC is equivalent to using the [[PeriodicXPIC Custom Task]] with <tt>FMPMOrder</tt> 1 (''i.e.'', PIC style) every time step combined with with [[MPM Methods and Simulation Timing#Classic MPM Methods\|<tt>Classic</tt> or <tt>B2Spline</tt>]] grid-based shape functions (the APIC paper is not clear which they used, but it was probably <tt>B2Spline</tt>). Like all PIC-style method, APIC can dissipate much energy in certain problems. Using higher <tt>FMPMOrder</tt> while tracking velocity gradient extends APIC to reduce dissipation using approximate full mass matrix methods.		Another paper relevant to velocity gradient tracking is the APIC method.<ref name="APIC"/>. APIC is equivalent to using the [[PeriodicXPIC Custom Task]] with <tt>FMPMOrder</tt> 1 (''i.e.'', PIC style) every time step combined with with [[MPM Methods and Simulation Timing#Classic MPM Methods\|<tt>Classic</tt> or <tt>B2Spline</tt>]] grid-based shape functions (the APIC paper is not clear which they used, but it was probably <tt>B2Spline</tt>). Like all PIC-style method, APIC can dissipate much energy in certain problems. Using higher <tt>FMPMOrder</tt> while tracking velocity gradient extends APIC to reduce dissipation using approximate full mass matrix methods.<ref name="FMPM"/> Switch to other available [[MPM Methods and Simulation Timing\|shape function]] extends APIC to methods that work better with large deformations.

	== Notes ==		== Notes ==

Nairnj: /* References */

2024-04-26T02:42:10Z

References

← Older revision		Revision as of 02:42, 26 April 2024
Line 55:		Line 55:

	<ref name="APIC">C. Jiang, C. Schroeder, A. Selle, J. Teran, A. Stomakhin, The Affine Particle-In-Cell Method, <i>ACM Trans ACM Trans Graph, SIGGRAPH</i>, (2015).</ref>		<ref name="APIC">C. Jiang, C. Schroeder, A. Selle, J. Teran, A. Stomakhin, The Affine Particle-In-Cell Method, <i>ACM Trans ACM Trans Graph, SIGGRAPH</i>, (2015).</ref>

			<ref name="FMPM">J. A. Nairn and C. C. Hammerquist, "Material point method simulations using an approximate full mass matrix inverse," <i>Computer Methods in Applied Mechanics and Engineering</i>, <b>377</b>, 113667 (2021). (2021). ([http://www.cof.orst.edu/cof/wse/faculty/Nairn/papers/FMPMPaper.pdf See PDF])</ref>

	<ref name="ASPaper">J.A. Nairn and J.E. Guilkey, "Axisymmetric Form of the Generalized Interpolation Material Point Method,"> <i>Int. J. for Numerical Methods in Engineering</i>, <b>101</b>, 127-147 (2015) ([http://www.cof.orst.edu/cof/wse/faculty/Nairn/papers/AxisymGIMP.pdf See PDF]).</ref>		<ref name="ASPaper">J.A. Nairn and J.E. Guilkey, "Axisymmetric Form of the Generalized Interpolation Material Point Method,"> <i>Int. J. for Numerical Methods in Engineering</i>, <b>101</b>, 127-147 (2015) ([http://www.cof.orst.edu/cof/wse/faculty/Nairn/papers/AxisymGIMP.pdf See PDF]).</ref>

	</references>		</references>

Nairnj: /* Tracking Velocity Gradient */

2024-04-26T02:40:54Z

Tracking Velocity Gradient

← Older revision		Revision as of 02:40, 26 April 2024
Line 39:		Line 39:
	When used in standard FLIP MPM, a revised extrapolation to the grid follows methods first presented by Wallstedt and Guilkey.<ref name="WGVG"/> The method used to track velocity gradients, however is different. The best approach to FLIP analysis with velocity gradient tracking is under evaluation.		When used in standard FLIP MPM, a revised extrapolation to the grid follows methods first presented by Wallstedt and Guilkey.<ref name="WGVG"/> The method used to track velocity gradients, however is different. The best approach to FLIP analysis with velocity gradient tracking is under evaluation.

	Another paper relevant to velocity gradient tracking is the APIC method.<ref name="APIC"/>. APIC is equivalent to using the [[PeriodicXPIC Custom Task]] with ~~order~~ 1 (''i.e.'', PIC) every time step combined with with [[MPM Methods and Simulation Timing#Classic MPM Methods\|<tt>Classic</tt> or <tt>B2Spline</tt>]] grid-based shape functions (the APIC paper is not clear which they used, but it was probably <tt>B2Spline</tt>). Like all PIC-style method, APIC can dissipate ~~a lot of~~ energy in certain problems. Using higher		Another paper relevant to velocity gradient tracking is the APIC method.<ref name="APIC"/>. APIC is equivalent to using the [[PeriodicXPIC Custom Task]] with <tt>FMPMOrder</tt> 1 (''i.e.'', PIC style) every time step combined with with [[MPM Methods and Simulation Timing#Classic MPM Methods\|<tt>Classic</tt> or <tt>B2Spline</tt>]] grid-based shape functions (the APIC paper is not clear which they used, but it was probably <tt>B2Spline</tt>). Like all PIC-style method, APIC can dissipate much energy in certain problems. Using higher <tt>FMPMOrder</tt> while tracking velocity gradient extends APIC to reduce dissipation using approximate full mass matrix methods.

	== Notes ==		== Notes ==