FAQ 000088 EN-US

12/01/2017

Robert Vogl Calculation RF-FE-LTB FE-LTB

When trying to select imperfections, I get the message "Diagonal coefficient of matrix less than zero." What have I done wrong?

Answer

The message means that your system is numerically unstable. Such an instability can be often explained by inaccurate support conditions or release definitions in FE-LTB.

When selecting imperfections and also in the calculation, the critical load factor will be specified. Based on this, the critical load of the system is determined.

In the numerical calculation, this stability load is characterized by the fact that either the determinant of the stiffness matrix becomes zero, or that very high deformations occur for very small load increments in the calculation.

Keywords

imperfection diagonal coefficient matrix critical load

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