Implicit simple restart fails with cohesive elements (ELFORM 19/-19)

- August 8, 2026 at 12:22 pm
  PL Zhang
  Subscriber
  Hello,
  
  I created a very simple LS-DYNA implicit model to test simple restart with cohesive elements.
  
  The model runs normally in a continuous implicit analysis. However, when I perform a simple restart using a d3dump file, the analysis fails in the first implicit step after the restart.
  
  I tested both:
  ELFORM = 19 ELFORM = -19
  and the same problem occurs with both cohesive element formulations.
  
  I have attached the minimal .k test model, as well as the corresponding messag files from the continuous analysis and the restart analysis.
  
  Is this a known limitation or bug related to cohesive solid elements in implicit simple restart? If simple restart is required for an implicit analysis, is there another cohesive element formulation that is recommended?
  
  Thank you.
  
  K file:
  $# LS-DYNA Keyword file created by LS-PrePost(R) 2025 R1 (v4.12.9) - 16Oct2025
  $# Created on Jul-1-2026 (16:49:32)
  *KEYWORD
  *CONTROL_ACCURACY
  $# osu inn pidosu iacc exacc srtflg
  1 4 0 1 2.0 0
  *CONTROL_BULK_VISCOSITY
  $# q1 q2 type btype tstype
  0.0 0.0 1 0 0
  *CONTROL_ENERGY
  $# hgen rwen slnten rylen irgen maten drlen disen
  2 2 2 2 2 1 1 1
  *CONTROL_HOURGLASS
  $# ihq qh
  6 0.01
  *CONTROL_IMPLICIT_AUTO
  $# iauto iteopt itewin dtmin dtmax dtexp kfail kcycle
  1 11 51.00000E-7 0.001 0.0 0 0
  *CONTROL_IMPLICIT_DYNAMICS
  $# imass gamma beta tdybir tdydth tdybur irate alpha
  0 0.5 0.25 0.01.00000E281.00000E28 0 0.0
  *CONTROL_IMPLICIT_GENERAL
  $# imflag dt0 imform nsbs igs cnstn form zero_v
  1 0.001 2 1 0 0 0 0
  *CONTROL_IMPLICIT_SOLUTION
  $ NSOLVR ILIMIT MAXREF DCTOL ECTOL RCTOL LSTOL
  $# nsolvr ilimit maxref dctol ectol rctol lstol abstol
  12 1 301.0000E-101.0000E-101.00000E-5 0.9 0.0
  $ DNORM DIVERG ISTIF NLPRINT NLNORM
  $# dnorm diverg istif nlprint nlnorm d3itctl cpchk
  -1 1 1 3 2 0 0
  $ DMTOL EMTOL RMTOL NTTOL NRTOL RTTOL RRTOL
  $# dmtol emtol rmtol - nttol nrtol rttol rrtol
  1.0000E-101.0000E-101.00000E-4 0.0 0.0 0.0 0.0
  $ ARCCTL ARCDIR ARCLEN ARCMTH ARCDMP
  $# arcctl arcdir arclen arcmth arcdmp arcpsi arcalf arctim
  0 0 0.0 1 2 0.0 0.0 0.0
  $# lsmtd lsdir irad srad awgt sred kssize
  6 2 0.0 0.0 0.0 0.0 10
  *CONTROL_IMPLICIT_SOLVER
  $# lsolvr lprint negev order drcm drcprm autospc autotol
  7 1 2 0 4 0.0 1 0.0
  $# lcpack mtxdmp iparm1 rparm1 rparm2 - rparm4 rparm5
  2 0 5001.00000E-9 0.001 240.0 0.0
  $# emxdmp rdcmem absmem isingle iblropt - ispd memlvl
  0 0.95 0.0 0 0 0 0.0
  *CONTROL_TERMINATION
  $# endtim endcyc dtmin endeng endmas nosol
  3.260E+01 0 0.0 0.0 0.0 0
  *CONTROL_TIMESTEP
  $# dtinit tssfac isdo tslimt dt2ms lctm erode ms1st
  0.0 1e-5 0 0.0 0.0 0 0 0
  $# dt2msf dt2mslc imscl unused unused rmscl emscl ihdo
  0.0 0 0 0.0 0.0 0
  *DATABASE_EXTENT_BINARY
  $# neiph neips maxint strflg sigflg epsflg rltflg engflg
  80 3 3 1 1 1 1 1
  $# cmpflg ieverp beamip dcomp shge stssz n3thdt ialemat
  0 0 4 1 1 1 2 0
  $# nintsld pkp_sen sclp hydro msscl therm intout nodout
  8 0 1.0 0 0 0STRESS STRESS
  $# dtdt resplt
  0 0 3
  *DATABASE_BNDOUT
  $# dt binary lcur ioopt option1 option2 option3 option4
  0.01 2 0 1 0 0 0 0
  *DATABASE_GLSTAT
  $# dt binary lcur ioopt
  0.01 2 0 1
  *DATABASE_MATSUM
  $# dt binary lcur ioopt
  0.001 2 0 1
  *DATABASE_SPCFORC
  $# dt binary lcur ioopt
  0.01 2 0 1
  *DATABASE_BINARY_D3PLOT
  $# dt lcdt beam npltc psetid
  0.001 0 0 0 0
  $# ioopt rate cutoff window type pset
  0 0.0 0.0 0.0 0 0
  *DATABASE_BINARY_D3DUMP
  $# dt lcdt beam npltc psetid
  1 0 0 0 0
  *LOAD_SEGMENT
  10001 0.5E6 0 13 14 16 15
  *DEFINE_CURVE
  $# lcid sidr sfa sfo offa offo dattyp lcint
  10001 0 1.0 1.0 0.0 0.0 0 0
  $# a1 o1
  0.000000000000E+00 0.000000000000E+00
  5.000000000000E-01 1.000000000000E+00
  6.000000000000E-01 1.000000000000E+00
  3.260000000000E+01 1.000000000000E+00
  *BOUNDARY_PRESCRIBED_MOTION_SET
  $# nsid dof vad lcid sf vid death birth
  2 1 2 10000 1.0 0 0.0 0.0
  *DEFINE_CURVE
  $# lcid sidr sfa sfo offa offo dattyp lcint
  10000 0 1.0 1.0 0.0 0.0 0 0
  $# a1 o1
  0.000000000000E+00 0.000000000000E+00
  6.000000000000E-01 0.000000000000E+00
  1.133333333333E+00 8.000000000000E-03
  2.200000000000E+00 -8.000000000000E-03
  2.733333333333E+00 0.000000000000E+00
  3.266666666667E+00 8.000000000000E-03
  4.333333333333E+00 -8.000000000000E-03
  4.866666666667E+00 0.000000000000E+00
  5.400000000000E+00 8.000000000000E-03
  6.466666666667E+00 -8.000000000000E-03
  7.000000000000E+00 0.000000000000E+00
  7.533333333333E+00 8.000000000000E-03
  8.600000000000E+00 -8.000000000000E-03
  9.133333333333E+00 0.000000000000E+00
  9.666666666667E+00 8.000000000000E-03
  1.073333333333E+01 -8.000000000000E-03
  1.126666666667E+01 0.000000000000E+00
  1.180000000000E+01 8.000000000000E-03
  1.286666666667E+01 -8.000000000000E-03
  1.340000000000E+01 0.000000000000E+00
  1.393333333333E+01 8.000000000000E-03
  1.500000000000E+01 -8.000000000000E-03
  1.553333333333E+01 0.000000000000E+00
  1.606666666667E+01 8.000000000000E-03
  1.713333333333E+01 -8.000000000000E-03
  1.766666666667E+01 0.000000000000E+00
  1.820000000000E+01 8.000000000000E-03
  1.926666666667E+01 -8.000000000000E-03
  1.980000000000E+01 0.000000000000E+00
  2.033333333333E+01 8.000000000000E-03
  2.140000000000E+01 -8.000000000000E-03
  2.193333333333E+01 0.000000000000E+00
  2.246666666667E+01 8.000000000000E-03
  2.353333333333E+01 -8.000000000000E-03
  2.406666666667E+01 0.000000000000E+00
  2.460000000000E+01 8.000000000000E-03
  2.566666666667E+01 -8.000000000000E-03
  2.620000000000E+01 0.000000000000E+00
  2.673333333333E+01 8.000000000000E-03
  2.780000000000E+01 -8.000000000000E-03
  2.833333333333E+01 0.000000000000E+00
  2.886666666667E+01 8.000000000000E-03
  2.993333333333E+01 -8.000000000000E-03
  3.046666666667E+01 0.000000000000E+00
  3.100000000000E+01 8.000000000000E-03
  3.206666666667E+01 -8.000000000000E-03
  3.260000000000E+01 0.000000000000E+00
  *SET_NODE_LIST
  $# sid da1 da2 da3 da4 solver its -
  2 0.0 0.0 0.0 0.0MECH 1
  $# nid1 nid2 nid3 nid4 nid5 nid6 nid7 nid8
  9 10 11 12 13 14 15 16
  *BOUNDARY_SPC_SET
  $# nsid cid dofx dofy dofz dofrx dofry dofrz
  2 0 0 1 0
  *BOUNDARY_SPC_SET
  $# nsid cid dofx dofy dofz dofrx dofry dofrz
  1 0 1 1 1
  *SET_NODE_LIST_TITLE
  NODESET(SPC) 1
  $# sid da1 da2 da3 da4 solver its -
  1 0.0 0.0 0.0 0.0MECH 1
  $# nid1 nid2 nid3 nid4 nid5 nid6 nid7 nid8
  1 2 3 4 5 6 7 8
  *MAT_ELASTIC_TITLE
  ROCK_OUTTER
  $# mid ro e pr da db not used
  1 2700 1.700E+10 0.23 0 0 0
  *MAT_COHESIVE_ELASTIC_TITLE
  COHESIVE
  2 1.000E-06 1 0 2.400E+09 3.000E+10 1.000E+20 1.000E+20
  *MAT_ELASTIC_TITLE
  ROCK_OUTTER
  $# mid ro e pr da db not used
  3 2700 1.700E+10 0.23 0 0 0
  *SECTION_SOLID
  $# secid elform
  1 2
  *SECTION_SOLID
  $# secid elform
  2 19
  *PART
  $# title
  boxsolid
  $# pid secid mid eosid hgid grav adpopt tmid
  1 1 1 0 0 0 0 0
  *PART
  $# title
  boxsolid
  $# pid secid mid eosid hgid grav adpopt tmid
  2 2 2 0 0 0 0 0
  *PART
  $# title
  boxsolid
  $# pid secid mid eosid hgid grav adpopt tmid
  3 1 3 0 0 0 0 0
  *NODE
  $# nid x y z tc rc
  1 0.0 0.0 0.0 0 0
  2 0.15 0.0 0.0 0 0
  3 0.0 0.15 0.0 0 0
  4 0.15 0.15 0.0 0 0
  5 0.0 0.0 0.075 0 0
  6 0.15 0.0 0.075 0 0
  7 0.0 0.15 0.075 0 0
  8 0.15 0.15 0.075 0 0
  9 0.0 0.0 0.075 0 0
  10 0.15 0.0 0.075 0 0
  11 0.0 0.15 0.075 0 0
  12 0.15 0.15 0.075 0 0
  13 0.0 0.0 0.15 0 0
  14 0.15 0.0 0.15 0 0
  15 0.0 0.15 0.15 0 0
  16 0.15 0.15 0.15 0 0
  *ELEMENT_SOLID
  $# eid pid n1 n2 n3 n4 n5 n6 n7 n8
  1 1 1 2 4 3 5 6 8 7
  2 2 5 6 8 7 9 10 12 11
  3 3 9 10 12 11 13 14 16 15
  *END
  
  messag01 file after simple restart:
  
  read d3dump1337 file
  
  BEGIN implicit statics step 1337 t=1.3370E+00
  
  Linear step computed
  Initial translational energy = NaN
  Initial total energy = NaN
  Initial residual norm = NaN
  Translational nodes norm = NaN

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LS Dyna

Implicit simple restart fails with cohesive elements (ELFORM 19/-19)

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