船舶机舱模型振声性能数值计算与试验验证

采用有限元/边界元法对船舶机舱动力设备及液舱流固耦合引起的振动与声辐射进行数值计算;并进行相应的实验研究。以某航海教学实习船机舱为原型,将此振声耦合系统简化为箱形多腔结构,运用数值有限元方法建立多腔结构及其单元腔室的模型,考虑流固耦合效应,对结构进行频率响应分析;然后采用边界元法对舱室辐射噪声进行了计算。计算结果与实验结果之间的误差在5 dB以内,表明本方法具有较好的准确度。采取两端简支的边界条件,研究三舱段船舶机舱模型振声性能时,充液及增加充液舱数,总体对改善舱室振声性能有利;但对于液舱接触舱室声学环境影响要分频段考虑,此外舱室距振源的距离对计算结果有较大的影响。

Computation and Measurement on Vibro-acoustic Characteristics of vessel engine room model

By using finite element method/ boundary element method, the numerical calculation and relevant experiment were carried out on the vibration and sound radiation caused by power equipment in vessel engine room and fluid-structure coupling in liquid tank. The engine room of one training ship for navigation teaching was taken as the prototype, and the vibro-acoustic coupling was simplified as the multi-tanks structure. The numerical finite element method was used to build multi-tanks structure and the model of its unit chamber. By considering the fluid-structure coupling interaction and conducting frequency response analysis, boundary element method was adopted to calculate the radiation noise in ship cabin. The error between computed result and experimental result is within 5dB, suggesting that the method has high precision. Two ends simply supported boundary conditions were used to investigate three cabins vibro-acoustic characteristics of vessel engine room model. Filling liquid and increasing the number of tanks filled with liquid are beneficial to the improvement of vibro-acoustic characteristics of vessel engine room. But the vibro-acoustic characteristics of ship cabin should be taken into account according to the frequency range when touching liquid tank. Besides, the distance between ship cabin and vibration source greatly influenced the computed result.