Showing results for 
Search instead for 
Do you mean 
Reply
Solved! Go to solution

Change Memory Allocation don't solve my problem

Guys I have to simulate a screw pull out in a vetebra bone. My contact(screw-bone) its ok. I check this on linear analysis. Now  And I using, initially solution 601, 106 on advanced simulation tool(NX 10). When I run the model pop up the following error on *.log file:

 

*** ERROR NO. A1101 ***

Mesh too distorted, Jacobian determinant not positive

 

Anyone can help me with that. Actualy, I´m using Advance

 

 

1 REPLY
Solution
Solution
Accepted by topic author Wissenechaftler
‎08-26-2015 04:32 AM

Re: Change Memory Allocation don't solve my problem

Hello!,

You have a "distorted mesh" problem, nothing to see with memory allocation. In general (without the problem in hand)  the distorted mesh is caused by excessive displacement within iteration. The reasons of the large displacement could be a few:

  • Too large time steps: decrease the time step size (simply increase the number of times steps, for instance use 100 time steps and see how solution progress).
  • You could have rigid body motions: contact not defined correctly.

I suggest to simplify your model, reduce nonlinearities, or at least do not include all your nonlinearities together since the beginning, identify sources of nonlinearity and reduce them until solution converges.

 

For geometric nonlinearity:

  • Use small strain instead of large strain (LGSTRN)
  • Use small displacement instead of large displacement (LGDISP)

For material nonlinearity:

  • Extend material curves to avoid element rupture (XTCURVE)

For load nonlinearity:

  • Use deformation independent loading (LOADOPT)
  • Apply loads more gradually

For contact nonlinearity:

  • Add or remove friction.
  • Use small displacement contact instead of large displacement contact (CTDISP).
  • Add contact compliance (CFACTOR1).
  • Increase friction regularization parameter (EPST).
  • Gradually remove initial penetrations (INIPENE/TZPENE).

Well, the above are basic procedures in nonlinear analysis using NX NASTRAN Advanced NonLinear Module (SOL601), but each nonlinear problem is a world, please be patient & methodical and test the different options, OK?.

Best regards,

Blas.

Blas Molero Hidalgo, Ingeniero Industrial, Director
IBERISA • 48004 BILBAO (SPAIN)
WEB: http://www.iberisa.com
Blog Femap-NX Nastran: http://iberisa.wordpress.com/