Optimization of substructure dynamic interface forces by an energetic approach

A method based on an energetic approach has been developed to optimize vibration isolation at low frequencies. The aim is to minimize the dynamic response of a main structure (car body, rocket core…) subjected to interface forces generated by connected substructures (engine, booster…). At first, using a direct approach, an eigenvalue problem is formulated by minimizing the average dissipated power flow resulting from external load work. In order to keep a strong mechanical meaning, a modal approach has been developed to obtain an analytical expression of these eigensolutions. Then, the energy introduced in the structure at a given frequency is characterized by projecting the junction forces on the previously calculated basis. Both approaches have been numerically studied on an academic discrete system. The method has then been applied to a simple multimode coupled structure.