Adopting acoustic transfer vector (ATV) concept, the finite element method (FEM) and boundary element method (BEM) were combined to predict noise-radiation of the engine body. The procedures were as follows: The dynamics characteristic was analyzed with FEM software ANSYS, while the normal surface vibration exciting forces forwarded to the engine body were calculated based on multi-body dynamic model assembled by block, crankshaft, connecting rod, and piston. A BEM model was built in software SYSNOISE to calculate its ATV of the boundary vibration velocity to the sound field. Finally a 4-cylinder diesel engine SF480 was taken as an application example. The results show that the skirt part of the diesel engine is the main noise source at the speed in mid-high frequency domain, and the peaks frequencies are corresponded to the natural frequencies of the block.%结合有限元法(FEM)和边界元法(BEM),采用虚拟样机技术对内燃机噪声辐射的频域特性进行预测分析.其步骤为:用有限元软件ANSYS进行结构动态特性分析;建立机体、曲轴和连杆、活塞等组成整机多体动力学模型,求解传递给机体的各种激励力;采用声学分析软件SYSNOISE建立机体的边界元模型,分析其表面振动速度与声场间的声学传递向量(ATV).研究结果表明:在额定工况下,其机体裙部是主要噪声辐射部位;辐射声功率级较突出的峰值频率与整机固有频率基本对应,在中高频段其噪声辐射效率比低频段的高.
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