## Simulation Mechanical and Multiphysics

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# Error shuts down simulation in Mechanical 2013

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Simulation runs for a while and then fails. This error is in the log file: Error occurred with module: C:\PROGRA~1\Autodesk\SIMULA~1\srunx.exe

Whats going on? Is there a fix for this?

# Re: Error shuts down simulation in Mechanical 2013

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Hi Scott,

What type of analysis are you performing?

The first thing to try is to run the simulation again. My computer will cause the same problem every now and then, but running the exact same model does not produce the error. (No doubt something is going on inside the computer that delays one step in Simulation which causes a problem when the next step is attempted.)

If the problem is repeatable, you need to figure out when the error occurs. Does it occur while loading parts? During the solution of the matrix? While calculating the stresses? So, the steps to avoid the problem vary but can usually be figured out from the last 20 or so lines of the log file. (The log file and summary file -- both of which are output by the processor during the simulation -- can be viewed from the Report tab.)

Mechanical Engineer

Pittsburgh, PA

16 years experience with Simulation Mechanical

# Re: Error shuts down simulation in Mechanical 2013

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Thanks. I am running a static stress analysis. I tried rebooting, running the simulation numerous times. Tried suppressing different parts, etc... I get this message in he status window after the error:

**** Condition of the preconditioned system = 2.6693E+15

the matrix is probably ill-conditioned or singular, please

check model's fixities

Any ideas?

Here is a paste of the error log:

Autodesk (R) Simulation Static Stress with Linear Material Models

Version 2013.02.00.0010-W64/X64 02-Oct-2012

Copyright (c) 2012, Autodesk, Inc. All rights reserved.

-------------------------------------------------

DATE: MARCH 27, 2014

TIME: 10:31 AM

INPUT MODEL: C:\Users\JSW FabWorks\Dropbox\JSW FabWorks\Projects\Probe AKS\Spooler\LD Spooler.ds_data\6\ds

PROGRAM VERSION: 201302000010

alg-win-x64.dll VERSION: 201302000010

agsdb_ar-win-x64.dll VERSION: 201302000010

algconfig-win-x64.dll VERSION: 201302000010

solvercallback-win-x64.dll VERSION: 201302000010

amgsolve.exe VERSION: 360000000

-------------------------------------------------

**** Model Unit System Settings:

--------------------------------------------

Unit System : English (in)

Force : lbf

Length : in

Time : s

Temperature (Absolute) : deg F (R)

Thermal Energy : in*lbf

Voltage : V

Current : A

Electrical Resistance : ohm

Mass : lbf*s^2/in

--------------------------------------------

1**** CONTROL INFORMATION

number of node points (NUMNP) = 76787

number of element types (NELTYP) = 52

number of load cases (LL) = 1

number of frequencies (NF) = 0

analysis type code (NDYN) = 0

equations per block (KEQB) = 0

bandwidth minimization flag (MINBND) = -1

gravitational constant (GRAV) = 3.8640E+02

number of equations (NEQ) = 225727

**** PRINT OF NODAL DATA SUPPRESSED

**** PRINT OF EQUATION NUMBERS SUPPRESSED

**** Hard disk file size information for processor:

Available hard disk space on current drive = 291166.781 megabytes

Gravity direction vector = 0.0000E+00 -1.0000E+00 0.0000E+00

1**** ELEMENT LOAD MULTIPLIERS

load case case A case B case C case D case E

--------- ---------- ---------- ---------- ---------- ----------

1 1.000E+00 1.000E+00 1.000E+00 0.000E+00 0.000E+00

Centrifugal force / angular acceleration

load case rot.rate ang.acc.

--------- ---------- ----------

1 0.000E+00 0.000E+00

**** Symbolic Assembly Using the Row-Hits Matrix Profile ...

**** Number of equations = 225727

Estimated maximum bandwidth = 2840

Estimated triangle matrix nonzeroes = 50843435

Symbolically assembled nonzeros = 4875668

**** Real Sparse Matrix Assembly ...

1**** STIFFNESS MATRIX PARAMETERS

minimum non-zero diagonal element = 2.7756E+05

maximum diagonal element = 4.3250E+16

maximum/minimum = 1.5582E+11

average diagonal element = 2.0289E+12

warning: max/min stiffness ratio = 1.5582E+11

maximum stiffness = 4.324951E+16 at eqn#47247, node=15756, DOF=Tz

minimum stiffness = 2.775615E+05 at eqn#136150, node=46309, DOF=Tx

in the upper triangle:

number of entries in the profile = 50843435

number of nonzeros = 4875473

**** Sparse Matrix Assembled

**** Invoking Parallel AMG Iterative Solver...

**** Load Case 1

**** Matrix might be not positive definite.

Specified tolerance = 1.0000E-06

Final relative residual (of scaled system) = 1.9205E+06

Number of iterations used = 105

**** Please try to use Sparse solver.

If it keeps failing, please check model's fixity

to make it statically solvable

**** AMG solver log file appended:

AMG Solver start

Preprocessing complete time 1.4s max memory 195.5MB

Setting up constraints time 3.7s max memory 218.2MB

Preconditioner setup complete time 3.7s max memory 220.6MB

Iteration 1 relative residual 0.110E+01

Iteration 2 relative residual 0.707E+00

Iteration 3 relative residual 0.496E+00

Iteration 4 relative residual 0.394E+00

Iteration 5 relative residual 0.264E+00

Iteration 6 relative residual 0.144E+00

Iteration 7 relative residual 0.105E+00

Iteration 8 relative residual 0.999E-01

Iteration 9 relative residual 0.103E+00

Iteration 10 relative residual 0.113E+00

Iteration 11 relative residual 0.150E+00

Iteration 12 relative residual 0.214E+00

Iteration 13 relative residual 0.367E+00

Iteration 14 relative residual 0.596E+00

Iteration 15 relative residual 0.914E+00

Iteration 16 relative residual 0.120E+01

Iteration 17 relative residual 0.157E+01

Iteration 18 relative residual 0.192E+01

Iteration 19 relative residual 0.251E+01

Iteration 20 relative residual 0.344E+01

Iterations complete time 11.5s max memory 231.1MB

Setting up constraints time 13.6s max memory 231.1MB

Preconditioner setup complete time 13.6s max memory 231.1MB

Iteration 1 relative residual 0.368E+01

Iteration 2 relative residual 0.191E+01

Iteration 3 relative residual 0.151E+01

Iteration 4 relative residual 0.170E+01

Iteration 5 relative residual 0.209E+01

Iteration 6 relative residual 0.213E+01

Iteration 7 relative residual 0.181E+01

Iteration 8 relative residual 0.133E+01

Iteration 9 relative residual 0.963E+00

Iteration 10 relative residual 0.743E+00

Iteration 11 relative residual 0.576E+00

Iteration 12 relative residual 0.454E+00

Iteration 13 relative residual 0.344E+00

Iteration 14 relative residual 0.282E+00

Iteration 15 relative residual 0.205E+00

Iteration 16 relative residual 0.140E+00

Iteration 17 relative residual 0.984E-01

Iteration 18 relative residual 0.842E-01

Iteration 19 relative residual 0.789E-01

Iteration 20 relative residual 0.864E-01

Iteration 21 relative residual 0.102E+00

Iteration 22 relative residual 0.135E+00

Iteration 23 relative residual 0.196E+00

Iteration 24 relative residual 0.284E+00

Iteration 25 relative residual 0.409E+00

Iteration 26 relative residual 0.565E+00

Iteration 27 relative residual 0.658E+00

Iteration 28 relative residual 0.860E+00

Iteration 29 relative residual 0.119E+01

Iteration 30 relative residual 0.185E+01

Iterations complete time 23.2s max memory 231.1MB

Setting up constraints time 27.4s max memory 231.1MB

Preconditioner setup complete time 27.4s max memory 231.1MB

Iteration 1 relative residual 0.112E+01

Iteration 2 relative residual 0.721E+00

Iteration 3 relative residual 0.429E+00

Iteration 4 relative residual 0.282E+00

Iteration 5 relative residual 0.201E+00

Iteration 6 relative residual 0.132E+00

Iteration 7 relative residual 0.108E+00

Iteration 8 relative residual 0.882E-01

Iteration 9 relative residual 0.755E-01

Iteration 10 relative residual 0.862E-01

Iteration 11 relative residual 0.111E+00

Iteration 12 relative residual 0.170E+00

Iteration 13 relative residual 0.250E+00

Iteration 14 relative residual 0.385E+00

Iteration 15 relative residual 0.572E+00

Iteration 16 relative residual 0.747E+00

Iteration 17 relative residual 0.711E+00

Iteration 18 relative residual 0.665E+00

Iteration 19 relative residual 0.712E+00

Iteration 20 relative residual 0.112E+01

Iteration 21 relative residual 0.193E+01

Iteration 22 relative residual 0.341E+01

Iteration 23 relative residual 0.646E+01

Iteration 24 relative residual 0.120E+02

Iteration 25 relative residual 0.191E+02

Iteration 26 relative residual 0.249E+02

Iteration 27 relative residual 0.257E+02

Iteration 28 relative residual 0.206E+02

Iteration 29 relative residual 0.166E+02

Iteration 30 relative residual 0.169E+02

Iteration 31 relative residual 0.235E+02

Iteration 32 relative residual 0.371E+02

Iteration 33 relative residual 0.548E+02

Iteration 34 relative residual 0.772E+02

Iteration 35 relative residual 0.998E+02

Iteration 36 relative residual 0.156E+03

Iteration 37 relative residual 0.239E+03

Iteration 38 relative residual 0.308E+03

Iteration 39 relative residual 0.354E+03

Iteration 40 relative residual 0.333E+03

Iteration 41 relative residual 0.355E+03

Iteration 42 relative residual 0.469E+03

Iteration 43 relative residual 0.745E+03

Iteration 44 relative residual 0.115E+04

Iteration 45 relative residual 0.187E+04

Iteration 46 relative residual 0.335E+04

Iteration 47 relative residual 0.622E+04

Iteration 48 relative residual 0.122E+05

Iteration 49 relative residual 0.252E+05

Iteration 50 relative residual 0.502E+05

Iteration 51 relative residual 0.972E+05

Iteration 52 relative residual 0.176E+06

Iteration 53 relative residual 0.448E+06

Iteration 54 relative residual 0.192E+07

Iterations complete time 55.3s max memory 231.1MB

AMG Solver end time 55.3s max memory 231.1MB

***** ERROR DETECTED - EXECUTION TERMINATED

Error occurred with module: C:\PROGRA~1\Autodesk\SIMULA~1\srunx.exe

# Re: Error shuts down simulation in Mechanical 2013

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# Re: Error shuts down simulation in Mechanical 2013

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The crash doesn't provide any clues, but the various messages throughout the log file indicates that your model may not be statically stable. Start by checking that each part of the model is prevented from translating freely in X, Y, Z or rotating about X, Y, Z. If your model includes surface contact (or gap elements), I suggest that you review the page "Perform Analyses with Gap Elements" in the Help documentation. Or if one part is very rigid (rigid elements, beam elements with large cross-section, thick plates, made from "no bendium" ;-) and another is very weak (thin plate elements, something made from water, etc), you may need to exagerate the stiffness of one or more parts in order to get a mathematically stable matrix.

The other suggestion is to change the type of solver from Automatic (which chose the Iterative solver in your analysis) to the sparse solver. This is done under "Setup > Model Setup > Parameters" and on the "Solution" tab.

Mechanical Engineer

Pittsburgh, PA

16 years experience with Simulation Mechanical