DOPTPRM, DISCRETE

DOPTPRM, DISCRETE
Bulk Data Entry
Discreteness parameter. Influences the tendency for elements in a topology optimization to converge to a material density of 0 or 1. Default DISCRETE=1. Recommended bounds are 0.0 and 2.0 for shells, or 3.0 for solids.

Improving Discreteness.

There are numerous ways to improve the discreteness of the resulting topology. A list of potential issues leading to indiscrete designs and how to address them are:

– Check the optimization setup. For instance, the volume fraction constraint could be too low relative to mesh size (i.e., low volume fraction can only be achieved with very fine mesh).

– The optimization has hit the maximum number of iterations and has not fully converged to a discrete design. Use DOPTPRM, DESMAX to increase that maximum.

– The discreteness might be improved by continuing the optimization for longer by reducing the objective tolerance with DOPTPRM, OBJTOL.
DOPTPRM, TOPDISC can be used to trigger an additional internal measure to improve discreteness.

– Even though the defaults are set in a way that they are optimal for most cases, sometimes changing the penalty using DOPTPRM, DISCRETE could help improving design discreteness. See more information on this parameter in Penalty for SIMP.