General Mechanical

General Mechanical

Prestressed piezoelectric modal analysis in Mechanical APDL – cause of fatal error

    • CW62
      Subscriber

      I have conducted a static piezoelectric analysis to apply prestress loads to a piezoelectric energy harvester in Mechanical APDL. I am now trying to conduct a linear perturbation modal analysis restarting from the final substep of the last load step of the static piezoelectric analysis; however, the simulation encounters the fatal error below:

      *** FATAL ***              CP =  1540.578  TIME= 19:54:24

       The low level memory manager failed to return a valid memory handle for a free operation. Pointer value: 2627480032. It is likely that the code is calling for a free with a pointer that was not allocated via the memory manager.

      Is anyone aware of the cause of such an error? Is there another procedure I can follow to conduct a prestressed piezoelectric modal analysis? Any help would be greatly appreciated. Thank you.

    • Daniel Shaw
      Ansys Employee
      Are there any error/warning messages issued before this final error? For example, any warning about small pivot terms.
    • CW62
      Subscriber
      These are the error/warning messages issued during the simulation.
      /COM,ANSYS RELEASE Release 19.1BUILD 19.1UP2018041819:03:25

      *** WARNING ***CP =226.734TIME= 19:03:53
      Boundary conditions, coupling, and/or constraint equations have been
      applied on all the contact nodes (for example 1794).Overconstraint
      will occur.For deformable-deformable contact, switch contact and
      target surfaces.

      *** WARNING ***CP =226.953TIME= 19:03:53
      Boundary conditions, coupling, and/or constraint equations have been
      applied on all the contact nodes (for example 4751).Overconstraint
      will occur.For deformable-deformable contact, switch contact and
      target surfaces.

      *** WARNING ***CP =226.953TIME= 19:03:53
      Boundary conditions, coupling, and/or constraint equations have been
      applied on all the contact nodes (for example 8943).Overconstraint
      will occur.For deformable-deformable contact, switch contact and
      target surfaces.

      *** WARNING ***CP =226.953TIME= 19:03:53
      Boundary conditions, coupling, and/or constraint equations have been
      applied on all the contact nodes (for example 11900).Overconstraint
      will occur.For deformable-deformable contact, switch contact and
      target surfaces.

      *** WARNING ***CP =226.953TIME= 19:03:53
      Overconstraint may occur for Lagrange multiplier or MPC based contact
      algorithm.

      *** WARNING ***SUPPRESSED MESSAGECP =226.953TIME= 19:03:53
      Boundary conditions, coupling, and/or constraint equations have been
      applied on certain contact nodes (for example 11900).

      *** WARNING ***SUPPRESSED MESSAGECP =239.094TIME= 19:03:54
      The Sparse Matrix Solver was not able to sufficiently utilize the GPU
      accelerator device(s) during this equation solution.This can be
      caused by one or more factors such as: the size of the system of
      equations being solved; using older or less powerful GPU hardware
      relative to the CPU core(s) involved; having insufficient available
      memory on the GPU device.The check for GPU performance terminates
      for the remainder of this session.

      *** WARNING ***SUPPRESSED MESSAGECP =251.438TIME= 19:03:55
      The view for graph plots is currently NOT changeable.
      To enable graph view manipulation, issue /GROPTS,VIEW,1.

      *** WARNING ***CP =315.938TIME= 19:04:00
      A reference current value times the tolerance is used by the
      Newton-Raphson method for checking convergence.The calculated
      reference CHARGE CONVERGENCE VALUE = 7.883514722E-20 is less than a
      threshold.This threshold defaults to 1.0-12 or is specified as
      MINREF on the CNVTOL command.Check results carefully.

      *** WARNING ***CP =1358.469TIME= 19:05:08
      A reference current value times the tolerance is used by the
      Newton-Raphson method for checking convergence.The calculated
      reference CHARGE CONVERGENCE VALUE = 2.10299423E-14 is less than a
      threshold.This threshold defaults to 1.0-12 or is specified as
      MINREF on the CNVTOL command.Check results carefully.

      *** WARNING ***CP =1882.844TIME= 19:05:43
      A reference current value times the tolerance is used by the
      Newton-Raphson method for checking convergence.The calculated
      reference CHARGE CONVERGENCE VALUE = 5.075944998E-15 is less than a
      threshold.This threshold defaults to 1.0-12 or is specified as
      MINREF on the CNVTOL command.Check results carefully.

      *** FATAL ***CP =2096.578TIME= 19:08:56
      The low level memory manager failed to return a valid memory handle for
      a free operation.Pointer value: 1340621376.It is likely that the
      code is calling for a free with a pointer that was not allocated via
      the memory manager.

      ************************************************************************
      The above error is non-recoverable by ANSYS
      ANSYS run terminated by the indicated error
      Current data base saved if possible.
      ************************************************************************
    • veyselkaba
      Subscriber
      Hello CW62 ,
      I have similar error like you . Did you find any solution. If you found , could you share solution with me ? Thank you
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