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Typical warning message from LUSAS Solver text output file (*.OUT):

***WARNING*** PLASTICITY COMPUTATIONS HAVE FAILED TO CONVERGE FOR ELEMENT P ATTEMPTING TO INVOKE A STEP REDUCTION (SBTS6 PROCESSOR)


Most common causes & links to solutions 

A nonlinear material model has failed to converge in the plastic domain. If step reductions are performed the problem might be resolved and convergence archived when using a smaller load factor. In such a case the above message is not a matter of concern. 

If the analysis fails to converge all together, the reason for the warning would require further investigation of the particular model. If a material yields and has been defined to become perfectly plastic (zero stress/strain gradient), the model may become unstable depending on the region and/extent affected in the model. Specifying a small rather than zero hardening gradient may resolve this by stabilising the solution.

More on nonlinear convergence

How to find the target Node or Element:

Solver error or warning messages are also scanned from Solver .out file and reported in Modeller Text Output window. By default the Text Output window appears at the bottom of the graphics window just above the Status Bar. This displays messages and warnings during a modelling session. Specific objects referred to in error and diagnostic messages in the text window by ID number in the form "Element P" may be identified using the identify object dialog. The Identify Object" dialog is invoked by double clicking on the message text. From this dialog the identified object may be selected, moved to the centre of the screen, scaled to fill the screen, have its properties displayed, or identified by an annotation arrow or a temporary indicator.

Element P can also be located in the model using Advanced Selection, activated by right- clicking with the mouse in the graphics window, or via:

Edit > Advanced Selection

Continued difficulties? Try the pivot checklist

 


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