Systems, condensed graphic representation

Phase diagrams are the graphical representations of the phase rule, and they are classified by the number of components as follows one-, two-, three-,. .. component systems. On the other side, the phase rule is the most important tool for verifying phase diagrams. If pressure is omitted as a variable, the number of variables in a system is two temperature and composition. The phase rule reduces to F=C—P-i-1 and in this form is referred to as the condensed phase rule or phase rule for condensed systems. As an example, let us discuss the appHcation of the phase rule on a simple three-component system A-B-C with one compound BC. 

A graphical representation of the condensed finite element model is shown in O Fig. 26.6 where the nodes of group b are completely vanished. In addition, the equations for the condensed stif iess matrix and load vector of substructure B are given which are required to calculate the condensed global system according to O Eq. 26.24. Looking at these two equations, the important conclusion can be drawn that the condensed model of substructure B is independent of the stiffness of substructure A. Thus, any changes in substructure A will be considered correctly and the same result as calculated from the entire structure will be obtained. 

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