A HYBRID ENERGY MODEL FOR PREDICTING HIGH FREQUENCY VIBRATIONAL RESPONSE OF THIN PLATES UNDER HEAVY FLUID LOADING

摘要

Energy Finite Element Analysis (EFEA) is a method developed for high-frequency structural response prediction in recent years. In this paper, a hybrid model is developed to improve the prediction levels of the current EFEA energy governing equation for the thin plate in contact with heavy fluid. The neglect of the contribution of direct field is the primary prediction source of error in EFEA especially when the damping is significant. In order to fix this issue, both the reverberant field and the contribution of direct field are considered in the derivation. The fluid loading effect is incorporated in the derivation of the governing equation of direct field component in terms of effective mass and total damping factor in polar coordinates. As for the reverberant plane wave component, instead of the driving point, the injected power is modified as the scattered energy arising from direct field located at the boundaries, which is in consistent with the formation mechanism. The overall vibrational energy is the linear superposition of both fields. Numerical simulations on a rectangular plate validate the hybrid model through the comparison with the analytical modal solutions and show that the proposed hybrid model has a more accurate prediction comparing with the classical EFEA results.