Plotting data for increments within an analysis Step


#1

User question:

Can I see or plot data for the increments throughout a Step?”.

Answer:

When an analysis for a Step is performed, there are a number of increments that the solver takes to get to the end of the step, this is defined by the maximum value of step.increments (integer). Currently, only the last increment is stored and plotted for two reasons:

  1. Usually we are most interested in the final increment as it represents the equilibrium state requested by the user.

  2. Storing all data both slows down the data extraction and makes the structure.results dictionary very heavy (of the order of 100-1000 MB+ for bigger models).

It is still under discussion if all increments should be optionally returned, although this would require re-organising of the structure.results layout. But a far more preferable, and arguably more flexible solution is the following:

  1. Determine the total load/displacements to apply.

  2. Break this up into a number of small stages e.g. divided by 10, 100 etc, in a constant distribution or otherwise.

  3. Apply many Steps in sequence, where all the small staged loads and displacements add up to the total you want.

  4. Access each “sub increment”/stage through its Step data as normal.

This method would give much more flexibility as you can precisely control each stage you want, as normally FE solvers will adaptively adjust their increments, and the spacing might not be even or to your liking. You can then chose very explicitly the number and distribution of the stages and manage the filesizes appropriately.