dear scholars!
I am writing multiple UMAT subroutine for progressive damage modelling of a composite pipe by ply discount method. When in my Abaqus modeling, I option the NLGEOM off, my job is running without any error. but when NLGEOM is on, I have this error "too many attempts made for this increment ..."
Is it necessary for choices on NLGEOM in modeling of progressive damage??
I option NLGEOM on in my model and then use 'Automatic stabilization: specify dissipated energy fraction 0.0002 and '. after submit it and running ......
I have this error " time increment required is less than the minimum specified the analysis....." . for fix this error, I change minimum increment size in step module to 1e-10. but again I have the same error"time increment required is less than the minimum specified the analysis....". I reduce this value to 1e-16 and my job start to running without any error. but my run time is tooooooooooooooooooooo long!!!!
How can I fix this?
can you help me please??!
https://www.sciencedirect.com/search?qs=NLGEOM%20option%20in%20progressive%20damage%20modelling&show=25&sortBy=relevance
dear @Md. Washim Akram
thanks for your reply.
I am studied this article and search the link. but I can't find answer of my question.
can you explain more?? please??!
With damage, NLGEOm has to be on, I think, because the geometry effectively changes when elements are removed/fail. In addition, strains are usually larger than 5%.
There are lots of possible causes for your convergence trouble, reducing the minimum time increment to a very small value usually does not help slving the udnerlying problem. You need to find the cause of the problems, there are lots of discussions on how to do that already on RG.
See, NLGEOM means Geometric Non-Linearity. By initially not opting for it, you are making the simulation to be Linear. In such linear analysis, the stiffness matrix is a constant and hence easy convergence is achieved.
But when you toggle on NLGEOM, you are allowing ABAQUS to consider Geomteric Non Linearity. Hence, the stiffness matrix is no longer constant and is varying. There are lots of reasons why a Non Linear simulation can abort- for that you need to provide your .cae or .inp file or further discuss about your model.
The reason for this error is that the solutions of the equations do not converge. You can solve this problem with proper partitioning, shrinking mesh size and changing the meshing technique.
- Badges
- Science topic
- Similar topics
- Biological Science
- Kinesiology
- Running