Based On Bond Graph Dynamic Substructure Method

Dynamic substructure method (DSM) is effective to deal with dynamical analysis, which has developed rapidly. So far, Rayleigh-Ritz is the theory's foundation to research DSM. The whole structure was divided into many substructures according to DSM, and mathematical modal was founded after dispersed limited degree of freedom respectively by using Newton Principle and mode superposition method to resolve the whole structure's modal.Because the traditional DSM is not very precise, the difference of results is large and mode will lose sometimes. Based on the bond graph which was used in modal analysis in my teacher's research, the paper puts forward dynamic substructure method, and expounds the free-interface modal synthesis method by the numbers, free-interface modal synthesis method to reduce three improved methods, fixed-interface modal synthesis method such as reduction of normal modes coordinate, reduction of interface coordinate and reduction of improving Ritz Bases, multiply degree of freedom system's mechanical impedance and admittance, main system and sub-system synthetic method, etc.. In the experiment of modal synthesis, fixed-interface modal synthesis of beam is conceived to prove its theory, and the data compared modal simulation with truth proves its correctness. The example further indicates this method, comparing with the traditional methods, is better in modal synthesis rate, higher precision, more information of mode. This method is more authentically reflecting system's truth in mathematics modal, and more applicable and more accurate in its result on state of inertia element and capacity elementThe results above give a new approach for solving modal analysis and big, complex system's modal information. It can satisfy actual need in engineering and is valuable in application.