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Method of Calculation for Low-Frequency Noise in a Vehicle Compartment
Published January 01, 1972 by Institution of Mechanical Engineers in United Kingdom
The report discusses and presents diagrams of a linear mathematical model simulating the acoustical properties of the interior space of a passenger compartment and which takes into consideration the nature and configuration of the compartment sides. This technique permits:
~development of an explanation how acoustical resonances of the compartment can amplify noises produced by the sides.
~determination of the influence of each of the sides on each acoustical mode.
~calculation of the role of each sheet metal panel in the total noise spectrum transmitted through a solid path to all points of the compartment.
~determination of influence of modification of the compartment sides (strengthening, clamping, insulating...) on the reduction of the maximum noise transmitted through a solid path.
As early as the draft design, certain important defects resulting from the coincidence of the resonance frequencies of the gears of the structure and of the interior space can be avoided. During the course of tests, tuning of the vehicle is facilitated, because these low-frequency defects cannot be effectively controlled through the utilization of insulation and modifications in the design of the sheet metal parts are often necessary.