摘要：An improvement to the Rayleigh-Ritz substructure synthesis method in physical co-ordinates is presented. It retains the main features of such method but with additional important advantages. The improvement presented is based on the fact that only the physical co-ordinates to be constrained are really required for assembling. The adoption of mixed co-ordinates retains only the physical coordinates required while the others are chosen in order to optimize the condition number of transformation matrices. The procedure done in a systematic manner leaves no free choice to the use; and leads to an optimal numerical behavior.
