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Advanced solver settings: Stiffness solution

For many of the solver options GSA uses a matrix solver. There are a number of options which allow adjustments to be made to the assembly of the stiffness matrix.

Definition​

Global stiffness factor

This allows a factor to be applied to the stiffness as a whole. Either stiffening the structure (>100%) or introducing more flexibility (<100%).

Stiffness matrix reduction

  • Limiting minimum:maximum stiffness ratio: this is the limit where Gss will trigger a warning about possible ill-conditioning problems.
  • Minimum stiffness distinguished from zero: this is the limit at which a stiffness is considered. Any stiffness value less than this value is considered to be zero.

Calculate error norm and condition number

Where there are reservations about the integrity of the model it is useful to get feedback on the solution. The error norm gives a measure of the error in the solution and the condition number gives feedback on the best accuracy that can be expected.These options allow for forcing of the calculation of the error norm / condition number of the matrix.

Save system files

The stiffness and mass/geometric stiffness matrices can be stored in matrix market format. This can then be loaded into programs such as MATLAB for further analysis.