| Noise in a vehicle passenger compartment is a significant aspect when ride quality is considered. Among various vehicle cabin noise problems, structural-borne noise such as booming has significant impact on the cabin's interior noise.; In this thesis, the focus is on the boom noise problem in an all-terrain tractor cabin. The tractor cabin is a typical lightweight structure, which emits strong boom noise when excited by the vibration from the operating engine. Due to the complexity of the cabin structure, a theoretical analysis of the structure-borne noise of the cabin, especially the low-frequency structure-borne noise, is not possible. Therefore, a numerical method, finite element (FE) technique is employed for the cabin noise analysis.; The FE approach is applied to predict the boom noise inside the tractor cabin. Cavity acoustic resonances-of the cabin are evaluated, and the acoustic resonant frequencies are quantified and identified in the research. A structural-acoustic FE model counting the interactions between the air fluid inside the cabin compartment and the cabin's exterior structure is presented on the basis of the investigation of the structural-borne noise. The noise level inside the cabin is obtained, and the frequencies characterized by peak noise levels within the boom noise frequency range are identified corresponding to the external excitations. The influences of sound absorption, structural damping, added mass and structural stiffener on the acoustic response of the cabin are quantified. A discussion on the measures to control the boom noise inside the cabin is also provided. |
