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Typical error message found in the LUSAS Solver text output file (*.OUT):
***ERROR*** ELEMENT NUMBER 369 ILLEGAL JACOBIAN DETERMINANT OF -0.3881E+01
CHECK NODE ORDER AND CHECK THAT ELEMENT IS NOT EXCESSIVELY WARPED (BVELYR PROCESSOR)
Most common causes & links to solutions
A Jacobian determinant is a measure used within LUSAS to give an accurate value of the current length, area or volume of an element. A magnitude of less than or equal to zero will automatically invoke this message and is typically caused
by on of the following:
- Load increment too large in a buckling analysis
When a geometrically nonlinear problem is being analysed, deformation of one or more elements may become excessive, e.g. the elements are inverting. This would occur when using a load increment which is too large. The solution is to use lower load factors in the nonlinear control dialog.
- Mesh refinement/ aspect ratio problems
When quadratic order elements are in use and the aspect ratio of elements is not close to 1:1, deformation of one or more elements may become excessive. Changing to linear order elements would generally trigger the warning:
***WARNING*** ELEMENT NUMBER 404 UNREASONABLY DISTORTED, RATIO LONGEST/SHORTEST SIDE = 11.79
(KLGEOM PROCESSOR)
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