Abstract: Based on the principles of mechanical mobility and structural dynamics some theoretical formulae of the plate assemblies with the ribs are presented. Some numerial results and computing examples are also given. These theoretical formulae will provide some principles for the dynamical analysis and noise, vibration control in the structures applied widely in engineering.

Key words: Mechanical mobility, Plate assemblies, Power flow, Assembly Design Intent, Computer-Aided Design, Mating Behavior, Mating Structure, Assembly Feature Pair