Construction D0 Radio Button is Disabled for Log(time) Curves
§22.214.171.124 of ASTM D2435-11 places several constraints on the t/4t construction:
- The dial reading at 4t should be greater than the initial dial reading plus 25% of the total displacement for the increment.
- The dial reading at 4t should be less than the initial dial reading plus 50% of the total displacement for the increment.
In some cases it's impossible to select a t/4t interval that meets both of the above criteria. When it encounter such a case the program disables the "D0 by construction" option.