NairnMPM Version History - nairnj/nairn-mpm-fea GitHub Wiki

Introduction

This page gives brief history of the main changes in various version of the NairnMPM code engine. The project started on google code, but when that stopped allowing updates, it was transferred to GitHub. The versions available on GitHub on since version 10, which was added 31 May 2015.

Version in the Code

The version number is coded in the constructor of the NairnMPM.cpp class:

	version=7;                          // main version
	subversion=2;                       // subversion (must be < 10)
	buildnumber=0;                      // build number

Version History

The versions currently in this project are as follows:

  • Current master branch, Version 18.0 fixes (from 17 April 2024)

    • New material types
      • TransIsoSoftening - anisotropic damage mechanics modeling for a transversely isotropic material
      • OrthoSoftening - anisotropic damage mechanics modeling for an orthotropic material
      • OrthoPlasticSoftening - combined anisotropic damage mechanics and Hill plasticity modeling for an orthotropic material
    • New failure surfaces (TIFailureSurface and OrthoFailureSurface) to support the new damage mechanics materials
    • Both Viscoelasticity and TIViscoelasticity were rewritten to use a new approach that allows them to model temperature and moisture dependent initial elastic properties.
    • Angular momentum and angular velocity archiving now includes rotational motion of individual particles about their center of mass by evaluating their velocity gradient
    • A RandSeed command in the Header element can specify a random number seed to help in developing stochastic modeling based on damage mechanics materials or if you use expressions that use random numbers
    • TrackError custom task was improved (and bug fixes)

  • Current master branch, Version 17.0 fixes (from 28 November 2023)

    • New material types
      • IsoDamageMech - isotropic or scalar damage mechanics modeling
      • IsoPhaseFieldSoftening - phase field fracture modeling
      • PhaseFieldDiffusion - custom task to implement phase field fracture modeling
      • TIViscoelastic - transversely isotropic viscoelastic material
    • PhaseField and Damage commands to add initial conditions
    • Multiple diffusion options for other transport processes
      • Concentration and ConcentrationFlux BCs extended for other transport
    • VTKArchive custom tasks
      • Can save history variables
      • Can use quantity:name to get alternate name into the VTK files
    • PeriodicXPIC custom tasks update for handle extra transport options
    • New hashing methods used to speed up multiple crack simulations
    • New methods to find J integral for interacting and intersection cracks
      • Paper submitted soon
    • FluidSource - custom tasks to inject fluid into a problem
    • Reservoir of particles - option to support options like FluidSource custom task
    • Global archive expanded
      • Archive extra transport
      • Archive concentration fluxes
      • Archive reservoir size
    • Spline2D - code for future uses
    • Many other minor changes not listed here

  • Version 16.0 fixes (from 2 March 2023)

    • Fixed bug that broke concentration flux boundary conditions
    • VTKArchive custom task can now save history date and can pick alternate names for quantities
    • Diffusion can optionally allow c/csat to exceed 1 (i.e, to reinterpreting meaning of csat as a reference state instead of a saturation state)
    • Pressure traction law updated for an issue related to zero crack opening displacement
    • Added mod(x,y) for remainder of x/y for user-defined functions

  • Current master branch, Version 16.0 (from 4 February 2023)

    • Viscoelaticity material improved to work better if rotations occur and minor bug fixes in energy calculations.
    • Many changes first posted on 4 FEB 2023 and the following lists most (but maybe not all) changes. Changes above were posted after that date.
    • FMPM options were added to improve modeling of transport equations
      • An extra option to avoid numerical diffusiong is to blend ransport FMPM with FLIP
    • Tartan grid with option for unequal elements sizes in the background grid.
    • LoadControl custom to allow PID control of rigid block applied forces
    • Reservoir of particles. Used when deleting particle and to support custom tasks injecting particles
    • FluidSource custom tasks added to inject particles from the reservoir.
    • Custom patching of grid to optimize parallelization.
    • Archiving particle sizes to help in some visualization and VTK exports.
    • ExtractMPM updated to new archiving options and can be run is menu command in NairnFEAMPM and NairnFEAMPMViz apps.
    • Particles can change size and visualization tracks it
      • Not used by built-in features, but available to those writing custom tasks
    • Cubic softening law added k parameter to set slope after initiation
    • New double exponential softening law
    • IsoPlasticity and IsoPlasticSoftening materilals improved plane stress methods
    • Weibull distribution for softening materials
    • Pressure dependent shear strength in isotropic softening
    • Property ramp input using text files
    • Hill plasticity add new method (HillStyle parameter) and a new one is now the default.
      • Added alphaMax for exponential softening
    • TrackError custom tasks added
    • ReverseLoad custom tasks can trigger on passing a peak value
    • swapz used to swap axes for all transversely isotropic and orthotropic materials
    • Improved ideal gas modeling and added option to do van der Waals gas modeled

  • Version 15.0 (27 February 2021)

    • Viscoelastic material added time-dependent bulk modulus and time-temperature superposition options.
    • PropertyRamp custom task added exponential option for the ramp shape.
    • Added FMPM (now published) for MPM with an approximate full mass matrix. The FMPM methods can be used for modeling of transport properties as well. Run FMPM simulations by using the updated PeriodicXPIC custom task.
    • Many improvements to traction laws used to model cohesive zones a crack. One new traction law, called MixedModeTraction, is based on a submitted paper it provides a new (and improved) method for modeling mixed-mode failure with cohesive zones. It fixes limitations of all prior models, including models used in finite element analysis (and implemented in commercial software like Abaqus). A paper on this new model is submitted.
    • Cracks can define a custom traction laws to be inserted when the crack propagates (it can override some previous methods and neede to allow some new simulation options).
    • A single MPM simulation can vary the number of material points per element in different regions.
    • A material property allowsCracks lets selected materials ignore cracks. It can be used for modeling one material inside a crack in another material such as to model cutting with a tool or hydraulic fracturing with a liquid.
    • Selected material types can model poroelasticity (as another variant of transport property modeling). All archiving options for concentration when doing diffusion calculations can now archive pore pressure results when doing poroelaticity calculations. Similar, all concentration boundary conditions have corresponding poroelasticity boundary conditions.
    • Many additions for modeling using anisotropic damage mechanics:
      • A new material (IsoPlasticSoftening) was added that combines plasticity with damage mechanics.
      • A new option to couple damage mechanics evolution that appears more realistic (publication in preparation).
      • A custom task to delete damage particles (which sometimes helps in simulations). This task can also delete material points after a certain time (which is useful in creating some boundary conditions).
    • LeaveLimit and DeleteLimit commands provide new options for dealing with particles that leave the grid or develop NaN values.
    • HillPlastic material added two new options for hardening functions.
    • HEMGEOSMaterial added two new options for handling tensile loading.
    • New archiving options
      • Can archive history variables 1 to 19 (previously could only archive 1 to 4).
      • New traction laws added more history variables and you can archive traction history 1 to 10.
      • A new czmDisp option archives total dissipated energy per unit area by cohesive zones on crack particles.
      • Global archiving can track a crack's length or debonded length.
      • Global archiving can follow tracer particles.
      • ExtractMPM was update to support all new archiving options.
    • A new RestartScaling command will restart a time step if an implied displacement in extrapolated nodal values look too large.
    • The AdjustTimeStep was improved (parallelized) and added a maxIncrease parameter to be used in conjunction with the new RestartScaling option.
    • The default contact methods is now based on logistic regression (based on a now-published paper).
    • Non-regression contact methods were found to be inaccurate when using spline shape function methods and the contact law needed contact area (e.g., AdhesiveContact or imperfect interfaces). This issue was fixed.
    • A ReverseLoad custom task can now be triggered on debonded crack length.
    • Artificial viscosity support added for more materials.
    • Various features that read BMP files can now read more styles of those files.
    • ThermalRamp was changed to PropertyRamp and can ramp up more properties and can ramp based on BMP file data.
    • An experimental method to model generalized plane stress or plane strain in MPM is implemented for Isotropic materials.
    • A new cdfinv(p) function for expressions returns inverse to the cumulative normal distribution function.
    • Various bug fixes, such as:
      • Grid damping was broken and is now fixed.
      • Damage mechanics would mistakenly cool because crack opening was misinterpreted as elastic dilation. The issue is fixed.

  • Version 14.1 (from 17 August 2019)

    • IsoSoftening material to do anisotropic damage mechanics modeling
    • Softening and Damage initiation laws for use with IsoSoftening material
    • XPIC(k) methods for noise reduction and stabilization
    • B2GIMP can be used in axisymmetric modeling (but appears unstable near the origin - use B2CPDI instead)
    • CPDI and B2CPDI shape functions can be truncated (CPDIrcrit command) to work in parallel even with large deformations.
    • A method to exactly integrate tractions is available (ExactTractions command), but difficult to see any improvement over prior methods.
    • Global archive can archive decohesions (that occur in damage mechanics) and can archive tracer particles
    • Expressions have added some new function options
    • Removed fraction PIC options - use Periodic XPIC custom tasks instead
    • Imperfect interfaces improved when have large tangential deformation
    • VTKArchive adds selectMaterial and the output files work better in ParaView
    • Two new contact options - displacement only mode and interfacial stiffness parameter DC. This provide options, but not recommended for general use. They are off by default
    • The Mie-Gruneisen equation of state materials work better at large compression (although should be used in conjunction with AdjustTimeStep custom task to insure stability).
    • The Johnson Cook hardening law has two new parameters
    • Boundary conditions using RigidBC particles are improved
    • A new velocity wall boundary condition that can sent boundary gradient too is available
    • Viscoelastic material was improved. The linear pressure law was returned to small-strain methods and enhanced to allow plane stress simulations. A small error in dissipated energy calculations was fixed

  • Version 13.0 (from 3 December 2018)

    • Spline shape functions (B2Spline, BSGIMP, and B2CPDI)
    • Initially deformed materials are allowed (to a limited extent)
    • Better reading of bit map files
    • RigidBC and RigidContact material types (old Rigid still works)
    • Improved way to move crack surfaces and updating stresses close to crack planes
    • Improved contact methods and internal calculations
    • In contact, displacement check always true and contact by Vmin not used
    • Improved Anisotropic plastic material
    • Revised traction methods
    • Ideal gas improved and added artificial viscosity
    • Tait liquid added artificial viscosity
    • New expression options (and internal code rewritten)
    • Java app (NairnFEAMPMViz) update to support new features
    • CompareGlobal tool added
    • XCode project updated to use clang 7.0 and to build CompareGlobal tool
    • VS projected undated for new code and added CompareGlobal sub project

  • Version 12.1 (to 2 December 2018)

    • ClampedNeohooken can run in elastic mode for modified co-rotated, neo-Hookean model
    • Two new contact laws - "AdhesiveFriction" and "LiquidContact"
    • Internal revisions to heat energy calculations and transport task methods. Heat energy calculations may change slightly. Transports task calculations (thermal and diffusion) should be identical but written to allow future improvements).
    • Various minor changes and improvements.
    • Switched to clang-mp compiler instead of Gcc when using XCode on Mac
    • Updated Visual Studio project for recent file changes

  • Version 12.0 (to 9 April 2016)

    • Grid and Particle boundary conditions are now all done with a single GridBC or ParticleBC command in scripts (or <BCShape> in XML files). Each boundary condition block can use any shape to select nodes or particles to get the boundary conditions.
    • Contact and interface calculations improved (small but noticeable improvements)
    • ContactPosition has new option that improves contact detection when using displacements
    • Regions can set initial particle velocity using a function of position
    • BMPRegion can set three Euler angles for 3D simulations of anisotropic materials by using three angle mask bit mapped files
    • Added project and change source to allow compiling in Visual Studio on PC
    • Arc options for Rect and Oval when using shapes to set up mesh
    • New Line and Arc shape for 2D problems in Line for 3D simulations
    • Cut command to allow nested shapes to add and remove particles
    • New <MPMArchive> command for XML input files
    • ThermalRamp custom task can set temperature field from an image file

  • Version 11.4 (until 4 Dec 2016)

    • Most materials now include coupling term between elastic dilation and heating (compression heats and tension cools). These allow heating effects whenever in a non-isothermal mode.
    • Prior thermal ramp commands have been replaced by a thermal ramp custom task.
    • Revised many memory error handlers. While these almost never happens, it is possible some things that would crash without explanation might now explain the problem.

  • Version 11.3 (14 Aug 2016)

    • Synched many changes and added some features from development OSParticulas code
    • Fixed bug adding crack tractions due to cohesive laws
    • Fixed parallel bugs in move cracks (if many cracks) and in reset elements tasks
    • Added linear and angular momentum to options for global archiving
    • Add Kmax property to HEMGEOSMaterial and Viscoelastic materials to add stability when compression exceeds fit range of the Mie-Gruneissen equation of state
    • TaitLiquid can archive shear rate in a history variable
    • No have five strain update methods (USF, USL+, USL-, USAVG+, and USAVG-)
    • HeatFlux BC's used to ignore the time variable to start the flux; it is now supported

  • Version 11.1 (13 Jan 2016)

    • Synched many changes and added some features from development OSParticular code
    • Friction and imperfect interfaces implementation all rewritten use the new "contact laws." Addition of custom contact laws is not difficult.
    • Static and dynamic coefficient of friction in new CoulombFriction contact law
    • AdjustTimeStep task looks at particle velocities as well deformation (needed most when modeling liquids)
    • Crack surface movement changed (based on theory) and looks better
    • Viscoelastic material added an option to find pressure using Mie-Gruneissen equation of state
    • Viscoelastic material had a bug for more than one lifetime (bug was fixed)
    • Improved heat flow calculation, frictional heating, and added archive for global friction work
    • Plastic energy consistently tracks irreversible entropy for material that dissipate energy. Entropy tracks reversible and irreversible where reversible entropy is isoentropic heating.
    • Heating due to friction now uses a second order calculation for improved convergence.
    • Two rigid materials contacting same nonrigid material is handled by using the dominant rigid material.
    • Boundary condition rigid particles can optionally extrapolate to the grid before setting boundary conditions. This option can help when rigid particle velocities depend on position (such as in shear deformation)
    • Each material can use custom particle damping or PIC damping.
    • Grid body force can now be a function of time and position.

  • Version 11.0 (14 AUG 2015)

    • Major changes to version 10 to allow new ConsistendUnits mode
    • All low strain material were converted to work better for large rotation problems and have two options for rotation calculations (see largeRotation material property). The main improvements are better reporting of strains and more accurate treatment of anisotropic materials. Note however, this this feature was not fully working until revision 1174.
    • Global archiving of contact force can get force on one material
    • Global and VTK archiving for deformation gradient

  • Version 10 (31 May 2015)

    • Has NairnMPM 10.x
    • Added two new damping options - particle damping and PIC damping; the later can also run simulations with mixed FLIP/PIC style updates. In making this change, also changed the way grid damping is implemented, but it should not make much of a difference.
    • Mooney can take E and nu OR K and G1. HEIsotropic and HEMGEOSMaterial can take G or G1.
    • Mooney, HEIsotropic, and HEMGEOSMaterial were revised to better handle residual stresses
    • Neohookean material as alternative to Mooney in its Neohookean mode. These two Neohookean materials used different strain energy functions.
    • New ClampedNeohookean material is hyperelastic-plastic material with softening based on critical elongations
    • HEMGEOSMaterial in tension was changed for better stability during large temperature changes.
    • ReverseLoad custom task can be triggered on any global quantity as well as crack length and it can hold for a specified time before reversing (or aborting). Finally, it had a bug using the hold style with load and traction BCs; the bug is fixed.
    • J integral calculations improved, especially when the contour encounters other cracks. A new gridenergy option might stabilize J calculations when crack tip has variations in kinetic or work energy on the particles.
    • Improved updating of crack plane when using the avg method, as long as the crack surface updating works well.
    • Added option to archive if selected number of propagations and/or debonds occur.
    • VTKArchive custom task can now archive volume gradient vectors and the number of points extrapolated to each node.
    • Selected materials can share material velocity fields in multimaterial mode.
    • PressureTraction law added a minCOD parameter to require some crack opening before the pressure is applied.
    • The internal coding for the Viscoelastic material was rewritten using internal variables. The new version now adds support for axisymmetric calculations and should correctly calculate dissipated energy (which can be converted into heat in adiabatic simulations).
    • Crack methods improved for interacting and intersecting cracks, for moving of crack surfaces, and for applying traction loads to nodes near cracks.
    • NairnFEAMPMViz add many new features including support for running calculations on a remote server and improved 2D graphics with option to output PDF version of the plots.
    • Can specify contact normal (if known).
    • The TaitLiquid can now set an initial pressure.

  • Release-5.0 (9 Feb 2014): On Jan 14, 2014, the OpenMP branch replaced the main trunk for this release. That branch was started on April 2, 2013 to make parallel code. It has lots of changes needed to be parallel. All MPM materials use buffers for any material class variable that changes with particle state. The entire problem is divided into patches with ghost nodes on boundaries (and some section divide work by patch). The Particles reordered by type, which helps some loops divided by type (e.g., rigid velocities). The crack velocity field calculation is done in the initiation phase. Many other changes have been done along the way, although many of these are just features and not crucial for parallel code:

    • Has NairnMPM 10.0.0
    • May 16: Torus object for 3D
    • May 22: Changed Johnson-Cook when above TM to be better
    • May 29: Heat flux BCs
    • July 26: Pyramid object for 3D and designation of symmetry planes for improved contact calculations.
    • Aug 6: Rigid contact materials all combined to single crack velocity field which is much better for rigid material within a crack. In the future might want regular materials to ignore cracks too (to wedge open crack with metal, for example).
    • Aug 13: Fixed bug in rigid particle z direction and z symmetry planes
    • Aug 23: Added option to track reaction forces at velocity and/or at rigid particle BCs. Also improved tracking of contact forces to use only post-update contact calculations (which agrees much better with expectations).
    • Sept 17: J integral approximately deals with interacting cracks by averaging velocities field of other cracks it encounters along the J contour. This change also fixed a velocity field bug that has long been in J calculations, but probably caused very small errors.
    • Sept 22: New traction law to apply constant normal stress on crack surfaces.
    • Oct 9: friction heating supported
    • Oct 25: J fields averaging to approximately support interacting cracks
    • Nov 7: crack initialization parallized
    • Nov 18: allow time step in functions
    • Dec 5: Symmetry plane boundary condtions
    • Dec 9: mirror property for rigid material for better BCs
    • Dec 10: Artifical viscosity uses total volume raters
    • Dec 19: New energy and heat traction and changes to achieved quantities. Also tracks entropy and can archive internal energy and Helmholz free energy.
    • Dec 20: Tait liquid finished and seems fairly sound, although some instabilities.
    • Jan 2: Fixed 3D bug introduced Dec 11, 2013
    • Jan 8: All documentation simplified with the details moved to the OSUPDocs wiki page
    • Jan 22: Added Shell shape command for 3D simulations

  • Prior trunk version of release 5.0 (until 14 JAN 2014 - it was replaced by parallel branch; all additions below are in the new trunk)

    • Working on NairnMPM 9.2.0
    • Prints svn revision number of code used in output files
    • Hardening Laws have been separated from materials to allow one to select them independently - this approach creates a large number of material types. An alternate nonlinear hardening law is among the previously available hardening laws.
    • MGSCGLMaterial has been replaced by MGEOSMaterial that use a Mie-Grüneisen law for pressure and can pick any hardening law. This material has also be greatly improved for more accurate tracking of internal energy (as needed in the pressure law) and to allow artificial viscosity useful in shock wave calculations.
    • SLMaterial, JohnsonCook, and VonMises materials have been eliminated. Instead use the new IsoPlasticity or MGEOSMaterial and then select any hardening law.
    • The HEIsotropic hyperelastic-plastic material is now fully developed. It can use any hardening law.
    • A new HEMGEOSMaterial implements Mie-Grüneisen law for pressure and hyperelastic methods for shear. It can use any hardening law.
    • Thermodynamics of deformation is now better modeled. Materials now track work and heat energy separately and their sum is internal energy. Mechanical energy coupling for adiabatic process can now be used with conduction on or off.
    • The Mooney material has an option to model an ideal rubber elastic material that heats on stretching and cooling on contraction. The material also tracks entropy change and during isothermal loading in the new ideal rubber mode, force is given by f = -(dS/dL)T. This material now also allows three difference energy function for pressure calculations.
    • The IdealGas material now tracks entropy change.
    • The VTKArchive can archive several new quantities.
    • Crack tips now track material type to all propagation between materials in a composite.
    • Fixed bug in J calculation

  • release-4.0 (9 JAN 2013)

    • Has NairnMPM 9.0.0
    • Addition of axisymmetric option for MPM. It does not yet do J integral and a few materials types do not support it yet (the code will not run if you use an unsupported material). A paper on axisymmetric MPM has been submitted.
    • Multmaterial mode contact can now implement imperfect interface laws in addition to friction laws. It is set up with Friction commands in MultiMaterialMode command or in material definitions.
    • Two new Normals option for multimaterial mode were added. One finds the volume-weighted average volume gradient of the contacting materials (it has been made the default normals method) and the other is classic MPM method of using each material's own gradient (it is not recommended, but available for comparison). Recent work on contact has shown all normal methods can have problems. The best solution is to specify a known normal. When that is not possible, another option is to use Vmin option of MultiMaterialMode command to screen out contact nodes near free edges. These recommendations are in a submitted paper on imperfect interfaces in MPM contact.
    • Overall improvements in contact mechanics.
    • Added CPDI (convected particle domain integration) as option to GIMP command (2D and 3D)
    • Added TractionBC to apply loads to surfaces rather then directly to particles (which can reduce artifacts in particles with external loads)
    • The grid now supports 1, 4, 9, 16, or 25 particles per cell in 2D and 1, 8, or 27 in 3D and both GIMP and CPDI work for all options.
    • Added DefGradTerms to pick how many terms used in the new exponential expansion to find the incremental deformation gradient for hyperelastic materials. The default 2 is recommended.
    • The flux boundary condition for diffusion is now much better. It uses the real surface integral term in MPM diffusion analysis.
    • Finished Johnson-Cook material.
    • The MGSCGLMaterial can now do plane stress calculations
    • BCBox for particle or velocity boundary conditions can specify an axis to change it to a cylinder
    • All internal objects based on BodyObjectController were changed to derive from generalized ShapeController. The changes allowed several body object controllers to be deleted.
    • Cracks are now represented in a hierarchical binary tree. This new representation allows dramatic increase in efficiency for curved cracks or for any crack not aligned with x or y axes.
    • Added ideal gas material implemented as a hyperelastic material.
    • The RigidMaterial code has been improved to allow independent control of velocities in x, y, and z directions (direction = 0 to 7), each axis can use its own function, and the functions can depend on position and time. This change allows, for example, to have rigid materials move in a circular motion.
    • RigidMaterials for contact (direction=8) can now use separate functions for each coordinate to simulate more types of motion and the function can now depend on position and time.
    • RigidMaterials that set temperature or concentration with a function now use a new valueFunction property and it can be a function of position and time. Because temperature and concentration functions were set before using settingFunction, old files will have to be updated to this new method.
    • Body forces for gravity were not correctly implemented for 3D before, but now work in 3D simulations.
    • Cylinder shape can add radius attribute to create a cone shape.
    • A new CoupledSawTooth traction law is implemented.
    • New HistoryArchive custom task to archive particle history data to tab-delimited text files.
    • New AdjustTimeStep custom task to adjust time step depending on particle state, but only for material types that can calculate a particle-state-dependent wave speed.
    • The skewed velocity condition had little use and has been removed. To get it just apply two conditions for x and y directions separately.
    • A new -w option to map relative files relative to the working directory rather than the input file.

  • release-3.0 (25 JAN 2012)

    • Has NairnMPM 8.1.0
    • Converted to using Xerces 3.1.1 and must link to 3.x or newer because new Xerces is not compatible with Xerces 2.8 or older.
    • Converted all longs to ints to avoid any potential machine-dependent issues in 64 bit compiles (NairnMPM can compile as 32 bit or 64 bit, and must match Xerces library bits)
    • Found bug in some 2D contact depending on machine/compiler combination and how they treated un-initialized doubles.
    • min, max, min+, etc. option in boundary conditions now enhanced to min+n, min-n (etc.) where n is an floating point number to specify number of cells relative to edge of the grid. This option can now also be used when using shapes to create material points.
    • Changed q in user-defined functions to mean rotation during the simulation rather then material angle it meant before. Changed in 8.0.1 and it will invalidate old input files that used q in functions on particles that started with non-zero rotation angle.
    • Rewrote MPMStep() to organize all tasks into task objects. The tasks can be profiled. A future plan is to optimize each task, perhaps for multi-core processors.
    • Added AltPropagate command to allow competing fracture modes. Its initial use is for competition between interface fracture and fracture turning into the bulk.
    • The default Vmin for multimaterial contact was changed to 0.0.
    • Added new RigidBias attribute for MultiMaterialMode command that takes the normal from the volume gradient of the rigid material unless the magnitude of the volume gradient from the non-rigid material is higher by the RigidBias factor. It only applies when normals=0.
    • Multimaterial mode that has contact with rigid particles can now track contact forces on the grid by using either a new VTKArchive custom task option or a new GlobalArchive option to archive a sum of all contact forces.
    • New Trilinear traction law material was implemented.
    • Revised movement of crack surface particles to include more small movements and to ignore large movements. It works much better with some new cutting simulations.
    • Improved traction laws so they can be used with interacting cracks.
    • VTKArchive option for total strain
    • Damping command can use a function to have grid damping that varies with time.
    • Polyhedron command for more 3D objects
    • Added Entity command.
    • Enhanced BMP command to allow specifying distance per pixel and to superpose multiple images.
    • The previous Mooney material (which was not really working correctly) was rewritten and expanded to full Hyperelastic material and works in 2D (plane stress and plane strain) and in 3D. A subset of this material is a Neo-Hookean material.
    • Commands that specify materials with mat attribute can now use matname instead to specify materials by name. Using mat and matname options in the same input file should be avoided.

  • release-2.0 (25 JUL 2009)

    • Has NairnMPM 7.3.0
    • The TriangularTraction and CubicTraction traction law were changed to provided a mixed-mode cohesive law (by methods used by Thouless) with exponential criterion with user-input exponent.
    • The TriangularTraction traction law was improved to allow peak position to be zero, which results in pure linear softening.
    • A new type of rigid materials (with SetDirection=8) that can do frictional contact in multimaterial mode. It can also be used to wedge open cracks.
    • Revised algorithm for preventing crack surfaces from crossing the crack plane and a new option to turn that feature on or off (see MovePlane command).
    • A minor change in the way crack surface velocities are calculated that should only effect cracks that exit the body, but those cracks are better done now using the exterior crack tip defined in version 7.2.0.
    • Blocked custom tasks from turning off extrapolations and added material field to custom task methods
    • Added unique attribute to ArchiveRoot command to force creation of new results subfolder on each run.
    • Added material option to the VTKArchive custom task.
    • Von Mises material has added one nonlinear hardening law; before it only had linear hardening.
    • Transversely isotropic, orthotropic, and Hill plastic materials can now do 3D. Rotation methods in Body command used to specify initial orientation of particles. All seem to work, but it is difficult to verify off-axis orientations. (Warning: any checkout for 7.2.2 had 3D working, but broke the 2D version for these materials only. It is fixed when version changed to 7.2.3. Also some rotations and transport rotations were not correct until version 7.3.0)
    • Rewrote Newton-Rapheson algorithm in anisotropic plastic materials (Hill plastic) to add bracketing, which should eliminate instabilities that were common with certain values for anisotropic yield stresses.
    • Archive format changed to ver6 to add archiving of 3 rotation angles of 3D particles needed for anisotropic materials.
    • More efficient at finding neighboring element when particles cross boundaries (2D, structured grid only)
    • Fixed error calculating particle mass for 3D grids when the elements were not perfect cubes.
    • Added PropagateLength command to select the amount of crack growth each time a crack propagates.
    • RotateZ (and Y and X) can now be used as alternate methods to set angles for MPM models read in using BMP files.
    • Added <DevelFlag> option in the <Header> for use in development coding.

  • release-1.0 (30 DEC 2009)

    • Has NairnMPM 7.2.0
    • MultiMaterialMode is supported with frictional contact
    • Automatically archives input command at (root).fmcmd
    • ContactPosition applies to both crack and multimaterials because it extrapolates displacement or position and never both
    • Added thickness attribute to grid. Cracks will use it and warn if set differently
    • Track interface energy in MPM with a global archive option
    • Revised material output with utility code methods
    • Updated code to compile in GNU 4.3.1
    • Rearranged x-y-z nodal point numbering to work better with 3rd-party visualization (like Paraview)
    • Added VTKArchive custom task to allow exporting of VTK Legacy files with grid data.
    • ver5 archive files to say if structured grid and to include archive time in ms
    • History archive can be Y, N, 1, 2, 3, -> 16 (using ASCII codes) to archive up to 4 history variables.
    • Also can global archive "history n"
    • Added MGSCGL material (not in NairnFEAMPM yet)
    • Added SL material (not in NairnFEAMPM yet)
    • Horiz, Vert, and Depth for the grid can specify cellsize rather than a number
    • BCLine, BCArc, BCBox, and LdRect can use min and max in coordinates
    • tolerance can be *f to be f * cell minumum size
    • Revisions led to new contact methods for cracks too.
      • Redid contact code - no longer interpret once, but interpret as needed
      • Similar changes in imperfect interface forces
      • Similar changes when moving crack surfaces (they may benefit further by looking for boundary condition velocities)
      • The move plave avg method uses a weighted average by mass extrapolated to each surface particle
      • Crack near edge can be designiated as exterior to mean crack plane is extrapolated but movement comes from within the body (by using tipmat=-1)

Archival Version History

Prior to being in GoogleCode.com, NairnMPM was in a local repository. That repository is available if needed. The prior versions are:

  • NairnCode2_0_0 (4 NOV 2008)

    • Has NairnMPM 6.6.2
    • Propagate into a traction material (and documentation of traction laws)
    • Add diffusion, condutions, and residual stress to 3D
    • 3D is all documented
    • Added <net> option to spread out total load equally over all found particles
    • Deleted Dugdale material
    • Improved Von Mises Hardening material and made it 3D as well
    • Added Hill Plastic - an anisotropic plastic material
    • LeaveLimit option to keep running even in particles leave the grid (they are moved back in)
    • Materials can have color, but only role is in programs that read the file
    • ContactPosition command to allow contact when crack surface were not initially in contact (approximately)

  • NairnCode1_5_0 (14 MAR 2008)

    • Has NairnMPM 6.5
    • SettingFunction in rigid materials for time-dependent settings.
    • Feedback damping added target kinetic energy option and global archive can record the feedback alpha
    • Adding option to have traction law between crack surfaces - it is currently undocumented and not completed

  • NairnCode1_4_0 (25 OCT 2007)

    • Has NairnMPM 6.4.0
    • Element crossings counted and can be archived
    • All materials now calculate szz and ezz, before elastic only found it when archiving (found error in prior szz and ezz in off axis, anisotropic materials now fixed)
    • Skewed velocity boundary conditions and skewed rigid particles
    • Arbitrary function of time and position allowed for all boundary conditions
    • Added base class isotropic diffusion and conductivity so it is now available in all materials. Aniostropic materials or those whose transport properties depend on particle state must override
    • Some material class reorganization such as printing to output window
    • Concentration flux boundary conditions.
    • Coupled moisture expansion and residual stresses and strains and all materials have moisture expansion coefficients
    • BCArc command for grid and particle BCs
    • Line and Circle in CrackList to create crack segments
    • Added MovePlane command for two ways to move crack plane. Also fixed some bugs found in crack surface movement, but only one one side of the crack had no particles
    • BMPRegion an have second mask to give orientation of particles too.
    • 3D for isotropic (no res stress, diffusion, conductions, cracks, gravity, custom tasks)
    • Some memory changes to only allocate data that are needed to allow larger calculations)

  • NairnCode1_3_0 (19 FEB 2007)

    • Has NairnMPM 6.3.0
    • LoadMechanicalProperties() always called before constitutive law. Can be used to change properties depending on particle state (stress, temperature, etc.). Replaces LoadMechProps(), which only had particle angle (and can still be used if angle is only property that matters).
    • New option to select method to find propagation direction
    • Implementation of spline methods to do crack calculations

  • NairnCode1_2_0 (8 FEB 2007)

    • Has NairnFEA 6.2.0
    • Fixed problem in transport calculations when points use same anistropic material but with different angles
    • Imperfect interface may be done - fixed problems that depending on location or orientation of interface
    • Started energy coupling between temperature and dissipated energy, but only in vonMises material and appears to be off by factor of 4

  • NairnCode1_1_0 (18 JAN 2007)

    • Has NairnMPM 6.1.0
    • Imperfect interface in place, but not yet done or documented
    • GIMP methods in 2D
    • Removed Update Strain Last option

  • NairnCode1_0_0 (22 DEC 2006)

    • Has NairnMPM 6.0.0
    • Beginning of 3D calculations, but not documented
    • Code reorganized and NairnFEA and NairnMPM combined into single NairnCode

Additional NairnMPM History

The following versions are from a prior repository and no longer available:

  • NairnMPM5_1_0 (14 FEB 2006)

    • Code reorganization to merge better with FEA code. All common FEA/MPM code was moved to "common" classes.
    • Creation of NairnMPM class which runs the calculations. The "main&qout; is now generic code for both FEA and MPM.
    • Created a class to handle reading of input files.
    • Created a class to handle archiving of results.
    • Moved nearly all global variables to member variables of main classes.

  • NairnMPM5_0_2 (05 DEC 2005)

    • Feedback damping as new damping options.
    • Prints version number used for calculations.
    • Many internal changes for more robust reading of input files and future coordination with FEA code.

  • NairnMPM5_0_0 (15 JUL 2005)

    • Added third digit in version number to hold build number after minor changes
    • Detects crack contact now by extrapolated displacement combined with velocity of the surfaces. Contact means crack surfaces are overlapped and that they are approaching each other.
    • Two new crack propagation criterion (6 and 7) or COD and on total energy release rate (J integral).
    • Velocity BC near crack modified to only set velocity for same side of crack
    • Will now detect crack leaving the mesh and will stop crack propagation when it happens
    • Isotropic work hardening for Von Mises material
    • Interacting cracks are possible
    • Silent boundary conditions added
    • Custom friction setting for each crack
    • Revised code to read XML files with "object" controllers
    • Fixed problem when velocity, temperature, or concentration boundary conditions were on a node but they did not start at time zero

  • NairnMPM4_0 (3 FEB 2005)

    • A new BMP option to create material points based on a gray scale image in a BMP file
    • An abort option (flag -a) will exit after setting up the problem and can be used to check the discretization of the problem
    • Many more commands can take an optional units attribute (see documentation for when allowed)

  • NairnMPM3_3 (19 NOV 2004)

    • Thermal conductivity started (only for isotropic materials and only with fixed temperature boundary conditions)
    • Crack tip heating started (but only for unit thickness)
    • Fixed cracks or cracks in which surfaces do not move cracks (for special uses)
    • Fixed crack propagation direction (for special uses)
    • Initiation time option for steady state crack propagation
    • Rigid materials (for moving velocity boundary conditions)
    • An option to ouput nodes and elements in separate text files (see Mesh definition)

  • NairnMPM3_2 (1 APR 2004)

    • More options for crack propagation
    • Support for linear viscoelastic materials completed
    • Addition of diffusion calculations (but in a preliminary way and not coupled to swelling strains)
    • These recent changes since NairnCode1_0_0 should be added to versions.html in documentation

  • NairnMPM3_1 (23 MAR 2004)

    • The XML input format was revised to make it more modular, make it easier to understand,
    • make it easier to read and maintain the DTD file, and to use better names for some tags. For example, all mesh creation commands are now in a <Mesh> element; all grid boundary conditions are within a <GridBCs> element; and are particle boundary conditions are within a <ParticleBCs> element.
    • The DTD file was added to the input folder of the checkout.

  • NairnMPM3_0 (18 MAR 2004)

    • Reorganized all headers
    • Added Mooney, Von Mises, Viscoelastic, and Bistable Isotropic materials
    • Custom tasks defined; some prior tasks moved to custom tasks and new ReverseLoad task to reverse applied load under any simulation-results condition
    • J Integral, stress intensity factor, crack propagation, and various other crack options
    • First version of Diffusion calculations (but uncoupled to stresses and only allows zero-flux or variable concentration boundary conditions). An example Diffusion.fmcmd file is provided.

  • NairnMPM2_2 (10 MAR 2003)

    • Reorganized all headers to make project easier to use as it gets bigger and to make it more compatible with NairnFEA code that is in development and will reuse some of the NairnMPM classes.

  • NairnMPM2_1 (31 JAN 2002)

    • Added transversely isotropic and orthotropic materials

  • NairnMPM2_0 (22 JAN 2003)

    • This is MPM code with fracture and has the newly revised method for archiving data.
    • As a first use of the new archived methods, the material points can now optionally archive particle strain energy and the separate components of the shear strain (du/dy and dv/dx).
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