挖掘机驾驶室低频结构噪声分析与优化*

针对某小型液压挖掘机驾驶室低频噪声过大问题,对驾驶室结构振动特性进行分析。基于有限元模型计算各工况下驾驶室噪声传递函数,运用统计学方法确定主要噪声峰值频率及相应工况;通过模态声学贡献度计算,确定危险工况下噪声贡献量较大的模态阶数,参照模态振型确定驾驶室振动变形最大的车身板件;并对该板件进行形貌优化处理,提高其一阶固有频率,进而降低驾驶室内噪声。优化结果表明,驾驶室噪声传递函数在危险频率下的峰值下降了2~4 dB。

Analysis and optimization of low frequency structural noise of excavator cab

Aiming at the problem of excessive low-frequency noise in the cab of a small hydraulic excavator, the vibration characteristics of the cab structure were analyzed. Based on the finite element model, the analysis of the noise transfer function of the cab under various operating conditions is calculated, and the peak frequency of the main noise and the corresponding operating conditions are determined using statistical methods. The modal acoustic contribution calculation is used to determine the mode with the larger noise contribution in hazardous conditions. The order of the modes is determined by referring to the modal shapes of the vehicle body panel with the largest vibration deformation in the cab. The shape of the panel is optimized to increase its first-order natural frequency, thereby reducing the cabin noise. The optimization results show that the peak value of cab sound pressure at dangerous frequencies has dropped by 2-4dB.