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

***WARNING*** ELEMENT NUMBER P UNREASONABLY DISTORTED, RATIO LONGEST/SHORTEST SIDE = Q (KLGEOM PROCESSOR)


Most common causes & links to solutions 

This message typically indicates the use of a poorly defined mesh. By nature, all FE analysis is an approximation, a "model" of a real (or potentially real) object. The results will be more accurate if the mesh is defined in such a way that simulates changes in geometry and load effects across the structure effectively. More on mesh refinement 

The particular problem being highlighted by this warning message is that the element P referenced may be long and thin; its "aspect ratio" (ratio of longest/shortest side) may be greater than 10. Because of the way that finite element calculations are performed, an ideal mesh would have a uniform "aspect ratio" of 1:1 across the whole model, but this is rather difficult to achieve and generally unnecessary. Elements with an aspect ratio around 5 should give reasonable performance, assuming the mesh is otherwise of suitable quality and refinement.

If the element aspect ratio is greater than 1:10 it may affect the nodal extrapolated results. More information on the aspect ratios is given in the Theory page regarding aspect ratio.

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


 

The theory behind the Jacobian matrix

Why mesh refinement is important

 


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