This information is part of the Modelica Standard Library maintained by the Modelica Association.

A flange is described by the connector class Interfaces.Flange_a or Interfaces.Flange_b. As already noted, the two connector classes are completely identical. There is only a difference in the icons, in order to easier identify a flange variable in a diagram. Both connector classes contain the following variables:

   Modelica.SIunits.Angle       phi  "Absolute rotation angle of flange";
   flow Modelica.SIunits.Torque tau  "Cut-torque in the flange";

If needed, the angular velocity w and the angular acceleration a of a flange connector can be determined by differentiation of the flange angle phi:

     w = der(phi);    a = der(w);