重型卡车驾驶室怠速噪声分析及控制

Analysis and Control of Idling Noise of a Heavy-duty Truck Cab

为降低某型重型卡车怠速噪声,建立驾驶室声-振耦合有限元模型,测试驾驶室四个悬置点被动侧加速度数据,以此作为仿真激励载荷计算驾驶室司机耳旁声压,仿真与试验结果具有较高的一致性。针对怠速工况32 Hz、64 Hz和96 Hz峰值频率,计算各频率的模态参与因子,对模态参与因子较高的模态阶次进行叠加,获取各峰值频率对应的模态应变能分布,作为怠速噪声的控制区域。对32 Hz峰值频率,采用局部结构加强的方式进行降噪处理,单频噪声衰减量5.2 dB;对64 Hz和96 Hz的峰值频率,采用在模态应变能集中区域布置阻尼材料的方式进行降噪处理,单频噪声衰减量分别为2.2 dB和3.5 dB。通过试验测试,怠速工况驾驶员耳旁声压级降低3.2 dB,表明降噪效果良好。

To reduce the idling noise of a heavy-duty truck cab,the acoustic-vibration coupling finite element model of the cab was established.Meanwhile,the acceleration data of the passive side of the four mounting points of the cab was measured and used as the excitation load to calculate the acoustic pressure near the driver's ear.Results of the calculation have a high consistency with the test results.For the peak frequencies of 32 Hz,64 Hz and 96 Hz in the idle condition,the modal participation factors of the frequencies were calculated.And the modal orders with higher modal participation factors were superimposed to obtain the modal strain energy distribution corresponding to each peak frequency,which was used as the idle noise control area.For the peak frequency of 32 Hz,the noise attenuation of 5.2 dB was obtained by using local structure strengthening method.For the peak frequency of 64 Hz and 96 Hz,damping materials were arranged in the area of modal strain energy concentration to reduce the noise,and the noise attenuation of 2.2 dB and 3.5 dB were obtained respectively.The test results show that the sound pressure level near the driver's ear is reduced by 3.2 dB at idle speed,which shows a good noise reduction effect.