Model failure after full restart

- January 19, 2026 at 1:30 am
  
  Joerg
  Subscriber
  
  Hello, I am modelling a soil column for a seismic analysis. First I run a gravity analysis for 10 sec incl. DR phase, which works fine. After the DR phase there are still some slight oscillations in the first 2sec, after that the model is perfectly still (in equilibrium). When I do a full restart however with the last d3dump, the model blows up. I do not change loading or boundary conditions in the restart deck, the only thing I change is I add the *STRESS_INITITIALIZATION card to tell Dyna its a full restart, extend the termination time to 20 sec, and in the *CONTROL_DR card I set idrflg to -999, since I should not need DR anymore as the equilibrated state should be imported (other than that the restart input is just a copy of the input file of the first run). However, very early on in the analysis the model distorts massively when viewing the d3plot output. The messag file of the restart run does complete, but says that the timestep got very large. The elout file only prints NaN for stress and strains... Hoping somebody can help me find out what is going wrong. (I know I could simply use the dynain file instead of restart, but then I always get these oscillations in the first ~2 sec. They are small, but anyway. I would like to know why the restart does not work...) Thanks
- January 19, 2026 at 1:34 am
  
  Joerg
  Subscriber
  
  I can't seem to be able to post the entire k file here, but these are my control parameters etc (same in both runs):
  *KEYWORD
  *PARAMETER_DUPLICATION
  2
  *DATABASE_FORMAT
  $ iform ibinary unused
  0 0
  *DATABASE_BINARY_D3PLOT
  $ dt/cycl lcdt/nr beam npltc psetid cid
  0.1 0 0 0 0 0
  *DATABASE_BINARY_D3DUMP
  $ dt/cycl lcdt/nr beam npltc psetid cid nskip
  0 8 0 1 0 0 0
  $ ioopt
  3
  *DEFINE_CURVE
  $ ID sidr sfa sfo offa offo dattyp unused1
  8 0 0 0 0 0 0
  $ a1 o1 unused1
  10 10
  *DATABASE_EXTENT_BINARY
  $ neiph neips maxint strflg sigflg epsflg rltflg engflg
  0 0 0 11 1 1 0 0
  $ cmpflg ieverp beamip dcomp shge stssz n3thdt ialemat
  0 0 0 0 0 0 0 0
  $ nintsld pkp_sen sclp hydro msscl therm intout nodout
  0 0 0 0 2 0
  *DATABASE_ELOUT
  $________I_________I_________I_________I_________I_________I_________I_________I
  $ dt binary lcur ioopt option1
  0.10 3 0 0 1 0
  *DATABASE_HISTORY_SOLID_SET
  $ id1 id2 id3 id4 id5 id6 id7 id8
  45 44 46 0 0 0 0 0
  *DATABASE_NODOUT
  $________I_________I_________I_________I_________I_________I_________I_________I
  $ dt binary lcur ioopt option1
  0.005 3 0 0 1 0
  *DATABASE_HISTORY_NODE_SET
  $ id1 id2 id3 id4 id5 id6 id7 id8
  55 54 56 0 0 0 0 0
  *DATABASE_GLSTAT
  $ dt binary lcur ioopt dthff binhf unused1
  0.02 3 0 0 0 0 0
  *DATABASE_MATSUM
  $ dt binary lcur ioopt dthff binhf unused1
  0.02 3 0 0 0 0 0
  *INTERFACE_SPRINGBACK_LSDYNA
  $ PSID NSHV FTYPE - FTENSR NTHHSV RFLAG INTSTRN
  802 0 0 0 0 0 0 0
  *CONTROL_TIMESTEP
  $ dtinit tssfac isdo tslimt dt2ms lctm erode ms1st
  0 0.9 0 0 0 0 1 0
  $ dt2msf dt2mslc imscl unused
  0 0 0
  *CONTROL_CONTACT
  $ slsfac rwnpal islchk shlthk penopt thkchg orien enmass
  0 0 1 1 1 0 2 0
  $ usrstr usrfric nsbcs interm xpene ssthk ecdt tiedprj
  0 0 0 0 0 0 0 0
  $ sfric dfric edc vfc th th_sf pen_sf unused
  0 0 0 0 0 0 0
  $ ignore frceng skiprwg outseg spotstp spotdel spothin unused1
  0 1 0 1 0 1 0.5
  $ isym nserod rwgaps rwgdth rwksf icov swradf ithoff
  0 0 0 0 0 0 0 0
  $ shledg pstiff ithcnt tdcnof ftall unused2
  1 0 0 0 1
  *CONTROL_ENERGY
  $ hgen rwen slnten rylen unused
  2 2 2 2
  *CONTROL_ACCURACY
  $ osu inn pidosu unused
  0 1 0 0
  *CONTROL_BULK_VISCOSITY
  $ q1 q2 type unused
  1.5 0.06 1
  *CONTROL_SOLID
  $ esort fmatrx niptets swlocl unused
  1 0 0 0
  $ pm1 pm2 pm3 pm4 pm5 pm6 pm7 pm8 pm9 pm10
  0 0 0 0 0 0 0 0 0 0
  *CONTROL_SHELL
  $ wrpang esort irnxx istupd theory bwc miter proj
  20 1 -1 0 2 1 1 1
  $ rotascl intgrd lamsht cstyp6 tshell nfail1 nfail4 psnfail
  0 0 0 0 0 1 1 0
  $ pstupd irquad cntco unused
  0 0 2
  *CONTROL_OUTPUT
  $ npopt neecho nrefup iaccop opifs ipnint ikedit iflush
  1 0 0 0 0 0 0 0
  $ iprtf ierode tet10 msgmax ipcurv unused
  0 0 0 0 0
  *CONTROL_PARALLEL
  $ ncpu numrhs consti para unused
  0 0 1 0
  *CONTROL_SOLUTION
  $ soln nlq isnan lcint unused
  0 0 0 600
  *CONTROL_HOURGLASS
  $ ihq qh unused1
  5 0.1
  *STRESS_INITIALIZATION
  *CONTROL_TERMINATION
  $ endtim endcyc dtmin endeng endmas unused
  20 10000000 0.001 0 100000
- January 19, 2026 at 1:36 am
  
  Joerg
  Subscriber
  
  The model itself I have in separate INCLUDE files (using same for both runs except as explained above)
  *INCLUDE
  01-Geometry.k
  *INCLUDE
  01-PART_SECTION.k
  *INCLUDE
  01-MAT_207_DR40.k
  *INCLUDE
  02-SET.k
  *INCLUDE
  03-BOUNDARY.k
  *INCLUDE
  03-FF_BOUND.k
  *INCLUDE
  03-RIGIDWALL.k
  *INCLUDE
  03-toplayer_DOFtied.k
  *INCLUDE
  04-PWP_DAMPING.k
  *INCLUDE
  05-LOAD_steady.k
- January 22, 2026 at 1:36 am
  
  Joerg
  Subscriber
  
  Seems like it was a BC issue. Still puzzled why the initial run seemed stable...