Home » Knowledge Base » Soil-Structure Interaction » PML in LS-DYNA

PML has been im­ple­ment­ed in LS-DY­NA for elas­tic, flu­id and acoustic me­dia, and may be used through one of the fol­low­ing cards:

  • MAT_­PML_­ELAS­TIC (MAT_­230), cor­re­spond­ing to MAT_­ELAS­TIC (MAT_­001)
  • MAT_­PML_­ELAS­TIC_­FLU­ID (MAT_­230_­FLU­ID), cor­re­spond­ing to MAT_­ELAS­TIC_­FLU­ID (MAT_­001_­FLU­ID)
  • MAT_­PML_­ACOUSTIC (MAT_­231), cor­re­spond­ing to MAT_­ACOUSTIC (MAT_­090)
  • MAT_­PML_­OR­THO/­ANISOTROP­IC (MAT_­245), cor­re­spond­ing to MAT_­OR­THO/­ANISOTROP­IC_­ELAS­TIC (MAT_­002 and MAT_­002_­ANIS)
  • MAT_­PML_­NULL (MAT_­246), cor­re­spond­ing to MAT_­NULL (MAT_­009); to be used on­ly with EOS_­LIN­EAR_­POLY­NO­MI­AL or EOS_­GRUNEISEN.

Please see the lat­est draft man­u­al for the in­put for­mat of each card.

Each PML ma­te­r­i­al is meant to be placed next to — and ab­sorbs waves from — a bound­ed do­main com­posed of the ma­te­r­i­al to which it cor­re­sponds. The ma­te­r­i­al in the bound­ed do­main near the PML should be lin­ear, and the ma­te­r­i­al con­stants of the PML should match those of the lin­ear bound­ed ma­te­r­i­al. To fa­cil­i­tate this, the in­put for­mat of each PML ma­te­r­i­al is large­ly sim­i­lar to the cor­re­spond­ing lin­ear ma­te­r­i­al.

Some fur­ther re­quire­ments for the PML ma­te­ri­als are:

  • The PML ma­te­r­i­al should form a par­al­lelepiped box around the bound­ed do­main, and the box should be aligned with the co­or­di­nate ax­es.
  • The out­er bound­ary of the PML should be fixed.
  • The PML lay­er may typ­i­cal­ly have 5–8 el­e­ments through the depth.
  • The PML ma­te­r­i­al should not be sub­ject­ed to any sta­t­ic load.