基于模态声学贡献度分析的挖掘机驾驶室噪声研究

发布时间：2018-02-14 14:53

本文关键词： 驾驶员耳旁噪声有限元法模态分析声学贡献度　出处：《山东大学》2016年硕士论文　论文类型：学位论文

【摘要】：挖掘机的广泛使用和挖掘机行业的迅速发展,人们对挖掘机提出了更高的使用性需求。除基本的工作使用性能,挖掘机的NVH性能优劣成为了各生产厂家相互竞争的焦点。驾驶室内噪声作为重要的NVH性能指标,关乎驾驶员的身心健康、工作效率以及生产安全。挖掘机驾驶室内噪声控制方法研究具有重要的实际意义和应用价值。本文结合履带式液压挖掘机噪声性能改进的工程实践,开展了基于模态声学贡献度分析的挖掘机驾驶室内噪声控制方法应用研究。首先,在总结国内外相关研究的基础上,提出了针对挖掘机驾驶室内噪声控制的模态声学贡献度理论框架。结合挖掘机结构特征,确定驾驶室和回转平台是驾驶室内噪声的主要影响结构,进而建立起了包含驾驶室、回转平台和减振器的结构有限元模型和驾驶室声腔有限元数值计算模型。其次,利用已建立的声固耦合模型计算了驾驶室和回转平台的结构模态以及驾驶员耳旁声压响应,在分析驾驶员耳旁声压频率特征的基础上,将主要的声压峰值频率确定为研究对象。在模态声学贡献度理论框架的指导下,分别计算了驾驶室和回转平台的结构模态对于峰值频率处声压的声学贡献度,提取了各峰值频率处声压的前三阶主导模态信息。最后,基于模态声学贡献度计算结果,在综合分析各主导模态振型特征的基础上,分别制定了驾驶室和回转平台的结构整改方案,并在仿真环境中验证了整改措施的有效性。样车试制后,通过试验采集了整改前后挖掘机驾驶室及回转平台关键部位的声振信号。对比发现,整改后的驾驶员耳旁1／3A计权声压级降低了2.2dB,同时,驾驶室及回转平台上各观测点在垂直方向上的振动加速度均方根值均出现不同程度的降低。结果表明,结构整改措施可有效降低以驾驶员耳旁噪声为代表的挖掘机驾驶室内噪声,对于振动性能亦有改善。基于模态声学贡献度分析的挖掘机驾驶室内噪声控制方法,建立起了系统的结构模态与声学响应之间的数学关系。在挖掘机驾驶室内噪声控制应用中,将驾驶室和回转平台的结构模态按照对于驾驶员耳旁声压的贡献程度排序,进而快速、准确地筛选出影响声压的关键结构模态,使结构整改工作有的放矢,为降低驾驶室内噪声提供指导。
[Abstract]:With the wide use of excavators and the rapid development of excavator industry, people put forward higher operational requirements for excavators. The NVH performance of excavator has become the focus of competition among manufacturers. As an important NVH performance index, noise in the cab is related to the physical and mental health of the driver. The research of noise control method in excavator cab has important practical significance and application value. This paper combines the engineering practice of improving the noise performance of crawler hydraulic excavator. Based on modal acoustic contribution analysis, the application of noise control method in excavator cab is studied. Firstly, based on the summary of relevant research at home and abroad, A theoretical framework of modal acoustic contribution for noise control in excavator cab is proposed. Combining with the structural characteristics of excavator, it is determined that the cab and rotating platform are the main influence structures of noise in the cab, and then the cab is established. The structural finite element model of the rotary platform and the vibration absorber and the finite element numerical model of the cab cavity. Secondly, the structural modes of the cab and the rotary platform and the response of the driver's sound pressure beside the ear are calculated by using the established acoustic structure coupling model. Based on the analysis of the frequency characteristics of the driver's ear pressure, the main peak frequency of sound pressure is determined as the object of study. Under the guidance of the theory of modal acoustic contribution, The acoustic contribution of the structural modes of the cab and the rotating platform to the sound pressure at the peak frequency is calculated, and the first three dominant modal information of the sound pressure at the peak frequency are extracted. Finally, based on the results of the modal acoustic contribution, On the basis of synthetically analyzing the modal characteristics of each dominant mode, the structural rectification schemes of the cab and the rotary platform are worked out, and the effectiveness of the rectification measures is verified in the simulation environment. The acoustic and vibration signals of the excavator's cab and the key parts of the rotary platform were collected by experiments. The comparison shows that the sound pressure level of 1 / 3 A weight of the driver's ear is reduced by 2.2 dB after the improvement. The root-mean-square values of vibration acceleration in the vertical direction of each observation point on the cab and the rotary platform are decreased to some extent. The results show that, The structural modification measures can effectively reduce the noise in the cab of excavator, which is represented by the driver's ear noise, and improve the vibration performance. The noise control method of excavator cab based on modal acoustic contribution analysis is presented. The mathematical relationship between the structural modes of the system and the acoustic response is established. In the application of noise control in the cab of the excavator, the structural modes of the cab and the rotating platform are sorted according to the contribution to the driver's ear sound pressure. Furthermore, the key structural modes affecting sound pressure can be quickly and accurately screened out, so that the structural rectification can be targeted, and the guidance can be provided for reducing the noise in the cab.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TU621

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