MPM Global Archiving Options

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Global archiving is an option to save selected calculated results in a single file. This section explains how to use this feature.

Introduction

In MPM calculations, the solution is stored in a series of archive files. You can optionally create a global results file which will store selected calculated result such as average stress, total energy, etc., in a single text file. This file can plotted latter in NairnFEAMPM or in NairnFEAMPMViz or can be opened later any spread-sheet software. The file is tab delimited with time (in alt time units) in the first column and all requested results in subsequent columns.

Input Commands

In script input files, global archiving is set up with the following commands: 

GlobalArchive (quantity),<(mat)>
GlobalArchiveTime (time)

In XML input files, global archive is set up with the following commands, which must be within the <MPMHeader> element: 

<GlobalArchive type='(quantity)' mat='(mat)'/>
<GlobalArchiveTime>1</GlobalArchiveTime>

where

  • (quantity) is the global quantity to be saved in the global results file. The case-sensitive options are:
    1. sxx, syy, szz, sxy, sxz, or syz - average element of the stress tensor in pressure units
    2. sRR, sZZ, sTT, or sRZ - average element of the axisymmetric stress tensor in pressure units (synonyms for sxx, syy, szz, and sxy)
    3. exx, eyy, ezz, exy, exz, or eyz - average element of the total Biot strain tensor in %.
    4. eRR, eZZ, eTT, or eRZ - average element of the axisymmetric total Biot strain tensor % (synonyms for exx, eyy, ezz, and exy)
    5. exxe, eyye, ezze, exye, exze, or eyze - average element of the elastic Biot strain tensor in %, which is tptal Biot strain minus plastic Biot strain for plasticity materials.
    6. eRRe, eZZe, eTTe, or eRZe - average element of the axisymmetric elastic Biot strain tensor % (synonyms for exxe, eyye, ezze, and exye)
    7. exxp, eyyp, ezzp, exyp, exzp, or eyzp - average element of the plastic Biot strain tensor in %
    8. eRRp, eZZp, eTTp, or eRZp - average element of the axisymmetric plastic Biot strain tensor % (synonyms for exxe, eyye, ezze, and exye)
    9. Fij (where i and j are x, y, or z) - any component of the total deformation gradient (absolute)
    10. Fij (where i and j are R or Z) - any component of the total axisymmetric deformation gradient (absolute, synonyms for the x or y versions).
    11. velx, vely, or velz - average component of velocity in velocity units
    12. velR or velZ - average component of axisymmetric velocity in velocity units (synonyms for velx or vely)
    13. dispx, dispy, or dispz - average component of displacement in length units
    14. dispR or dispZ - average component of axisymmetric displacement in length units (synonyms for dispx or dispy)
    15. contactx, contacty, or contactz - component of the total contact force on the grid for multimaterial mode simulations when they include rigid materials that have SetDirection=8. It is a sum of all contact forces for the rigid material on the object in Newtons.
    16. contactR or contactZ - component of the total contact force per radian on the axisymmetric grid in N (synonyms for contactx or contacty)
    17. reactionx, reactiony, or reactionz - component of the reaction force at nodes with velocity boundary conditions in N. If option (material) specifies a material, the force will be for all velocity conditions created by that rigid material; if (material) is omitted the force will sum all velocity boundary conditions (specified or created by rigid particles); if (material) < 0, the force will be only for velocity boundary conditions with that boundary condition ID.
    18. reactionR or reactionZ - component of the reaction force per radian at axisymmetric nodes with velocity boundary conditions in N (synonyms for reactionx or reactiony and see those options for meaning of the (material) option)
    19. temp - average temperature (when doing thermal calculations)
    20. concentration - weight fraction concentration (when doing diffusion calculations)
    21. Work Energy - total work energy in J, which is cumulative σ.dε
    22. Strain Energy - total strain energy in J, which is cumulative σ.(dε-dεres)
    23. Kinetic Energy - total kinetic energy in J on the particles
    24. Grid Kinetic Energy - total kinetic energy in J on the grid
    25. Heat Energy - total heat energy in J
    26. Entropy - total entropy in J
    27. Internal Energy - sum of work and heat energy (U = w + q) in J
    28. Helmholz Energy - total Helmholz free energy (A = U - TS) in J
    29. Interface Energy - total energy associated with cracks having imperfect interfaces in J.
    30. Plastic Energy - total plastic energy in J
    31. alpha - the total grid damping coefficient, αp(t), which is a combination of constant and feedback grid damping terms (in 1/sec)
    32. palpha - the total particle damping coefficient, αp(t), which is a combination of constant and feedback particle damping terms (in 1/sec) (OSParticulas only).
    33. Step number - the current MPM step number
    34. Elapsed time - elapsed clock time for the current calculation (in secs)
    35. CPU time - total CPU time for the current calculation (in secs)
  • The optional (mat) is the material ID for a previously defined material. Most of the global quantities are averaged over particles. You can specify this optional second parameter with a material ID and the average will be only for particles of that material type. Omit this parameter (or attribute) to indicate an average over all particles. Most quantites on the grid (e.g., Grid Kinetic Energy but not reactionx(y,z,R,Z) or contactx(y,z,R,Z)) will ignore the material ID.
  • The optional (time) is the time interval for storing global results. In scripted file, (time) is in milliseconds (it can be an entity). In XML files, it is in sec (or determined by a a units attribute). If the time interval is not specified, it will be set to the archiving interval specified in the archiving options. Specifying another time lets these two archiving times be different if desired.

Notes

  1. When global archiving of strains, they are calculated as a Biot strain in the current configuration. The Biot strain is defined is V-I where V is the left-stretch tensor. This strain is also the Seth-Hill strain with m=1/2 in current configuration. For small strain problems it is equivalent to the small strain tensor.
  2. You can store as many quantities as you want in the global results file by having any number of GlobalArchive commands, but only one option can be in each command. Each quantity will be in a labeled column in the global archive text file.
  3. The global archive text will be be stored at the path given in the archiving options with extension .global.
  4. Note that all terms involving heat ("Heat Energy", "Entropy", "Internal Energy", and "Helmholz Energy") will only be physically correct if all materials have specified their heat capacity.
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