Fyn_Anderson
Mechanical
- Nov 13, 2020
- 3
Hi everyone,
my friend and me are currently trying to simulate the tension and deformation of a pressure vessel due to inner pressure.
The model consists of a liner, two bosses (all of them isotropic) and an orthotropic laminate which we modeled using the continuum shell element.
We used position constraints to put the elements in the right position and used tie constraints for a simplified first case that does not consider friction between liner and laminate.
Afterwords we meshed all the parts. We partitioned the parts quite often in order to achieve a high ratio of structured mesh. We used Abaqus Standard for the solving procedure.
We then created the encastre bc on one side of the vessel (initial) and applied the load (step 2).
When running the job we get a single error and a lot of warning messages:
error:
The job input file "load.inp" has been submitted for analysis.
Job load: Analysis Input File Processor completed successfully.
Error in job load: Time increment required is less than the minimum specified
Error in job load: THE ANALYSIS HAS BEEN TERMINATED DUE TO PREVIOUS ERRORS. ALL OUTPUT REQUESTS HAVE BEEN WRITTEN FOR THE LAST CONVERGED INCREMENT.
Job load: Abaqus/Standard aborted due to errors.
Error in job load: Abaqus/Standard Analysis exited with an error - Please see the message file for possible error messages if the file exists.
Job load aborted due to errors.
Warnings:
4x:
Please make sure that the mesh density of the slave surface in the tie pair (assembly__t11_boss_2-1_s,assembly__t11_boss_2-1_m) is finer than the master surface. The analysis may run slower, may yield inaccurate results, and may require more memory if this is not the case.
several times:
Overconstraint checks: node 1 instance boss_1-1 is used more than once as a slave node in the *tie keyword. The constraint between this node and the master surface with node 291 instance laminat-1 is removed. Check if this is acceptable.
156 nodes are either missing intersection with their respective master surface or are outside the adjust zone. The nodes have been identified in node set WarnNodeMissMasterIntersect.
34 nodes are used more than once as a slave node in *TIE keyword. One of the *TIE constraints at each of these nodes have been removed. The nodes have been identified in node set WarnNodeOverconTieSlave.
310 elements are distorted. Either the isoparametric angles are out of the suggested limits or the triangular or tetrahedral quality measure is bad. The elements have been identified in element set WarnElemDistorted.
The aspect ratio for 34 elements exceeds 100 to 1. The elements have been identified in element set WarnElemAspectRatio.
78 elements are curved/warped. The angle subtended between the average element normal and a nodal normal exceeds 10 degrees. Mesh refinement is recommended. The elements have been identified in element set WarnElemWarped.
Excessive distortion or excessive rotation of the normal in 331 shell elements
FORCE equilibrium accepted using the alternate tolerance.
FORCE equilibrium accepted using the alternate tolerance.
What striked us is the fact that all Overconstraint Checks exist between laminate and bosses.
We have searched the internet for the error message but couldn't really figure out the reason for our simulation failure. A direction to move toward would help us a lot!
Thanks in advance.
my friend and me are currently trying to simulate the tension and deformation of a pressure vessel due to inner pressure.
The model consists of a liner, two bosses (all of them isotropic) and an orthotropic laminate which we modeled using the continuum shell element.
We used position constraints to put the elements in the right position and used tie constraints for a simplified first case that does not consider friction between liner and laminate.
Afterwords we meshed all the parts. We partitioned the parts quite often in order to achieve a high ratio of structured mesh. We used Abaqus Standard for the solving procedure.
We then created the encastre bc on one side of the vessel (initial) and applied the load (step 2).
When running the job we get a single error and a lot of warning messages:
error:
The job input file "load.inp" has been submitted for analysis.
Job load: Analysis Input File Processor completed successfully.
Error in job load: Time increment required is less than the minimum specified
Error in job load: THE ANALYSIS HAS BEEN TERMINATED DUE TO PREVIOUS ERRORS. ALL OUTPUT REQUESTS HAVE BEEN WRITTEN FOR THE LAST CONVERGED INCREMENT.
Job load: Abaqus/Standard aborted due to errors.
Error in job load: Abaqus/Standard Analysis exited with an error - Please see the message file for possible error messages if the file exists.
Job load aborted due to errors.
Warnings:
4x:
Please make sure that the mesh density of the slave surface in the tie pair (assembly__t11_boss_2-1_s,assembly__t11_boss_2-1_m) is finer than the master surface. The analysis may run slower, may yield inaccurate results, and may require more memory if this is not the case.
several times:
Overconstraint checks: node 1 instance boss_1-1 is used more than once as a slave node in the *tie keyword. The constraint between this node and the master surface with node 291 instance laminat-1 is removed. Check if this is acceptable.
156 nodes are either missing intersection with their respective master surface or are outside the adjust zone. The nodes have been identified in node set WarnNodeMissMasterIntersect.
34 nodes are used more than once as a slave node in *TIE keyword. One of the *TIE constraints at each of these nodes have been removed. The nodes have been identified in node set WarnNodeOverconTieSlave.
310 elements are distorted. Either the isoparametric angles are out of the suggested limits or the triangular or tetrahedral quality measure is bad. The elements have been identified in element set WarnElemDistorted.
The aspect ratio for 34 elements exceeds 100 to 1. The elements have been identified in element set WarnElemAspectRatio.
78 elements are curved/warped. The angle subtended between the average element normal and a nodal normal exceeds 10 degrees. Mesh refinement is recommended. The elements have been identified in element set WarnElemWarped.
Excessive distortion or excessive rotation of the normal in 331 shell elements
FORCE equilibrium accepted using the alternate tolerance.
FORCE equilibrium accepted using the alternate tolerance.
What striked us is the fact that all Overconstraint Checks exist between laminate and bosses.
We have searched the internet for the error message but couldn't really figure out the reason for our simulation failure. A direction to move toward would help us a lot!
Thanks in advance.
