DYNAMIC RESPONSE OPTIMIZATION OF A FLEXIBLE MULTIBODY SYSTEM BASED ON POWER DENSITY FLOW

To address the challenges in identifying energy transmission paths and optimizing the dynamic responses of flexible structures under complex and time-varying loads, this paper integrates the power density flow theory with a flexible multibody dynamic model to build a unified analysis-and-optimization framework. The Absolute Nodal Coordinate Formulation (ANCF), featuring full geometric nonlinearity and strictly continuous velocity fields across element boundaries, is employed to accurately capture local stress and velocity distributions and to enable faithful visualization and optimization of the power density flow. By combining the Green–Lagrange strain tensor with the elastic matrix, the theoretical expression for the vibration power density flow in a thin plate structure is derived, clarifying how stress and vibration velocity influence the energy propagation path and distribution. Using the power density flow analysis method, energy flow simulations are conducted for a satellite panel structure and a flexible double-link mechanism. A significant energy concentration is observed near connection points and hinge supports. Taking the energy density distribution as the optimization objective and keeping the total mass constant, the element thickness distribution is adjusted to mitigate the energy concentration effect. The optimization results show that the peak energy density of the flexible two-link mechanism is reduced by 68.5%, and the peak displacement response at the key position decreases by approximately 36%. For the satellite panel, the maximum energy density is reduced by 7%, and the peak displacement response at key positions decreases by about 12%, indicating a significant reduction in vibration levels. These results demonstrate that the proposed optimization method based on power density flow effectively compensates for the limitations of traditional modal analysis, providing a new energy-oriented strategy for structural response optimization and vibration suppression of thin-walled flexible structures such as spacecraft. The approach also offers practical significance for improving energy transmission uniformity and dynamic performance in complex loading environments.