zone ratio command

Syntax

zone ratio keyword

Primary keywords:

average    local    maximum    convergence

Please see Reaching Equilibrium. The ratio limit for mechanical and thermal calculations using the model solve can be calculated in three ways, as defined by the following keywords.

average

The ratio is defined to be the average unbalanced mechanical force (or heat-flux) magnitude for all the gridpoints in the model divided by the average applied mechanical force (or heat flux) magnitude for all the gridpoints. This is the default setting.

local

The ratio is defined to be the maximum value of the ratio of the unbalanced mechanical force (or heat-flux) magnitude to the applied mechanical force (or heat-flux) magnitude for all the gridpoints in the model. The ratio used is scaled by 0.1 to make it mean approximately the same as average.

maximum

The ratio is defined to be the maximum unbalanced mechanical force magnitude for all the gridpoints in the model divided by the average applied mechanical force (or heat flux) magnitude for all the gridpoints. The ratio used is scaled by 0.1 to make it mean approximately the same as average.

convergence

The ratio is defined as the maximum convergence of all the gridpoints in the model, with the convergence of a gridpoint defined as the local ratio divided by the target ratio . The ratio used is scaled by 1e-5 to make it mean approximately the same as average. For the zone thermal process this criteria is the same as local.

In increasing order of stringency, the conditions are:

average

ensures a majority of zones are in equilibrium.

maximum

ensures that all unbalanced forces are below a certain value, compared to average forces for the whole model.

convergence

ensures that each local unbalanced force is less than some fraction of the total forces being applied to a grid point. This criterion allows adjustment of the ratio-target, to allow relaxation of convergence criteria in regions specified by the user.

local

ensures that each local unbalanced force is less than some fraction of the total forces being applied to a grid point. This criterion can be misleading if some zones have very small stresses, because even a large ratio for one gridpoint may not be very important, given that the associated zone contributes almost nothing to the overall response.