General Mechanical

General Mechanical

How to restart with /prep7 commands?

    • Paulvh
      Subscriber
      Hello,nCurrently I am working on a problem that considers both NLADAPTIVE and element deletion command snippets in Mechanical. Unfortunately NLADAPTIVE does not support EKILL commands for element deletion. For that reason I would like to delete elements via the EDELE command. As this command is only valid in the /prep7 processor, I have to switch processors between loadsteps. The model consists of a gradually increasing displacement over multiple loadsteps. The problem I encounter when using the EDELE command in combination with ANTYPE restart is that the subsequent loadstep is considered loadstep n=1 (start at initial loading condition), while this should be n+1 (continue loading conditions).nI'm fairly new in writing my own commands, so I would like to learn how to properly deploy a restart for a subsequent loadstep that takes into account the adjustments (element deletion) made in the /prep7 environment in order to continue the simulation with the new mesh. Help is greatly appreciated!nKind regards,nPauln
    • Chandra Sekaran
      Ansys Employee
      Please refer to this section in the Basic Analysis Guide that gives a good overview of the restart process and also gives several examples. I am afraid though that you cannot delete elements when doing a restart. The document specifically states Material properties or elements cannot be changed during a restart. I am also pasting one example from this manual that gives you an idea of how to use the main commands : RESCONTROL and ANTYPE,,RESTARTn https://ansyshelp.ansys.com/account/secured?returnurl=/Views/Secured/corp/v202/en/ans_bas/Hlp_G_BAS3_12.html%23BASmultrestmap52199n/prep7net,1,21nr,1,1,1,1,1,1,1nn,1ne,1nfininn/solunantyp,transntimint,offntime,.1nnsub,2nkbc,0nd,1,ux,100 ! to apply initial velocity (IC command is preferrednsolvetimint,onnddele,1,ux ! this requires special handling by multi-frame restartn ! if a reaction force exists at this dof, replace it with an equal n ! force using the endstop optionntime,.2nnsub,5nrescontrol,define,all,1 ! request possible restart from any substepnoutres,nsol,1nsolvenfininn/solunantyp,,restart,2,3 ! this command resumes the .rdb database created at the start of solutionn ! (restart from substep 3nd,1,ux,100 ! re-specify boundary condition deleted during solutionnsolvenfininn/post26nnsol,2,1,uxnprvar,2 ! results show constant velocity through restartnfinishnnn
    • Paulvh
      Subscriber
      Hello CS,nThank you for your response. I guess I missed the part where I cannot change the mesh during a restart. Do you perhaps know another way that I can continue the simulation with a slightly adjusted mesh? (I was thinking of a way to write the required restart files, with the mesh changes included, so this can be initialized in the subsequent restart.)nKind regards,nPauln
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