Abstract: The frequency spectrum, where simulation methods can be utilized for vibration analysis, can be divided into three regions: low, mid and high frequency. This paper concerned mid -frequency vibration problems and the hybrid methods were developed to solve such problems. A beam-plate system was involved as an example to show the mid-frequency problem and to study the influence of boundary conditions on the effective impedance of fl exible members. The numerical results were obtained and compared with the dense mesh, coarse mesh and the hybrid methods.