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柴油机机架振动和振动产生的噪声总成谱在声频带范围内可看作是柴油机结构自由振动与引起柴油机零件撞击、推撞、干和半干摩擦的扰动力谱,是柴油机中的气动及其它过程的相互作用结果。此时可将扰动力看作是沿机架表面分布的,同时在一次工作循环中相位和振幅相互是无关的脉冲力,即在声频范围内激励谱是连续的。这就与运转的柴油机的激励谱基本相符。在噪声谱计算时用声辐射功率级L_N作为基本计算参数,因为此特性符合标准要求,并且完全能反映出柴油机噪声对周围介质的影响。这样,必须考虑到柴油机声辐射功率和表面振动功率
Diesel engine vibration and vibration generated by the vibration of the total spectrum in the audio band can be seen as the diesel engine structure free vibration and cause diesel engine parts impact, thrust, dry and semi-dry friction disturbance spectrum, is the diesel engine aerodynamic and Interactions of other processes. In this case, the disturbing force can be regarded as distributed along the surface of the machine frame. At the same time, the phase and amplitude are independent of each other in a working cycle. That is, the excitation spectrum is continuous in the audio frequency range. This is in line with the motivational spectrum of a running diesel engine. The acoustic radiation power level L_N is used as the basic calculation parameter in noise spectrum calculation because it meets the standard requirements and fully reflects the influence of diesel engine noise on the surrounding medium. In this way, the sound power of the diesel engine and the surface vibration power must be considered