轻型客车低频声—固耦合噪声传递路径分析与控制

发布时间：2019-06-04 17:24

【摘要】：随着汽车技术的发展与生活水平的提高,人们对汽车的乘坐舒适性要求逐日增高,而NVH性能是决定乘坐舒适性的重要指标。车内低频噪声问题作为整车NVH问题的一个重要组成部分,由其频率特征造成了其产生和传播过程相对复杂,较难分析噪声源及影响因素。因此,如何更加快速判断车内低频声-固耦合噪声产生的根源、更加准确确定对噪声有影响的主要部件、更有针对性的提出控制方案,以及在产品开发阶段如何准确预测、分析车内低频声-固耦合噪声等NVH问题,成为了各大汽车厂商和研究机构的主要研究方向。本文通过对某国产轻型客车低频声-固耦合噪声的传递路径分析及控制方法进行深入研究,建立了一整套能够快速、准确地预测、分析及控制低频声-固耦合噪声的理论方法与技术流程,丰富了TPA的分析理论与方法。针对车内低频声-固耦合噪声的研究和控制方法,以及传递路径分析的研究发展趋势进行了总结与分析,确定了本文基于传递路径分析理论对声-固耦合噪声进行研究的基本思路。本文系统地阐述了低频声-固耦合噪声传递路径分析的理论基础:推导了传递函数的理论及其无偏估计;详细介绍了三种工作载荷识别方法以及应用范围。重点推导了应用奇异值分解方法求解广义逆矩阵的过程。介绍了单参考传递路径分析和多参考传递路径分析。基于某国产轻型客车建立了整车低频声-固耦合噪声的TPA模型。该模型包括了以动力总成悬置,前、后悬架以及传动轴支撑为激励端,以人耳耳旁噪声为响应点的多条传递路径。基于此模型对整车低频声-固耦合噪声进行了传递路径分析。对以驾驶员、第二排乘客以及第五排乘客位置的耳旁噪声为响应点的多条传递路径进行了结构路径传递函数的测试;利用逆矩阵法获取了弹性元件被动端工作载荷。在进行传递路径分析之前,针对工况试验中的目标点数据进行了简要的车内NVH水平分析。结合主观评价与客观数据,确定70km/h时驾驶员耳旁位置以及第五排乘客耳旁位置存在噪声问题,并详细描述了噪声的主观感受。针对该工况问题频率下各主要位置进行传递路径分析,并提出了一种综合考虑声压级、幅值、相位的噪声传递路径贡献量评价方法。利用这种方法进一步针对每一个悬置进行了重新分组计算。初步确定了对不同频率、各个位置有主要影响的路径。为了深入分析低频噪声问题的产生机理及特征,本文建立了包含车身、车架、车门和车窗等在内的声-固耦合有限元模型。逐步建立了车架及白车身的有限元建模,并验证了仿真与和试验的模态频率基本吻合,模态振型一致。进一步建立了车窗及车门的有限元模型,并用正确的连接及约束方式连接,得到了门窗紧闭状态的整车模型。以整车有限元模型为基础,建立了考虑车内座椅的声腔有限元模型。进一步建立了整车声-固耦合模型,对耦合前后声腔和结构模态的特征进行了对比分析。将通过试验获取的材料吸声特性及结构阻尼施加到耦合模型上。为了验证低频声-固耦合模型,对车内噪声进行了混合传递路径分析并与试验传递路径分析的结果进行了对比,得到了较准确的低频声-固耦合模型。为了进一步体现tpa在分析、预测以及应用在研发初期时的优越性,本文建立了包含行驶系及b级路面的整车多体动力学模型,并将该模型与声-固耦合模型联合建立了整车声-固耦合噪声的虚拟tpa模型。基于低频声-固耦合噪声虚拟传递路径分析的结果,提出了综合考虑多频率、多响应点以及多工况的车内噪声综合传递路径分析方法,并进行了综合贡献量分析,确定了对轻型客车车内低频声-固耦合噪声贡献量较大的传递路径。从理论基础、分析结果、以及后续优化等三个方面对三种tpa方法进行分析,证明了虚拟tpa的优越性。针对贡献量最大的路径进行了单级以及次级传递路径分析。通过单级传递路径分析,确定了传递特性为需要优化的因素,并确定板件为需要优化的主要环节。针对板件环节进行了次级传递路径分析,并提出了一种考虑多频、多响应点、多工况以及相对关系的改进板件声学贡献量系数算法。基于该方法,进一步提出了板件声学影响系数的概念,并对其含义进行了说明。基于新的算法和概念进行了深入的次级传递路径分析,依据分析结果最终确定了需要控制的板件,实施了阻尼降噪措施,并通过仿真及试验的方法验证了降噪效果。由此证明了本文所提出的一系列理论及方法可以准确、有效、快捷地分析、控制、预测低频结构噪声。
[Abstract]:With the development of automobile technology and the improvement of living standard, people's riding comfort demand is increasing day by day, and the NVH performance is an important index to determine the ride comfort. The low-frequency noise in the vehicle is an important part of the NVH problem of the whole vehicle. The frequency characteristics of the vehicle are relatively complicated, and it is difficult to analyze the noise source and the influencing factors. Therefore, how to judge the root cause of the low-frequency sound-solid coupling noise in the vehicle more quickly and accurately determine the main components that have an effect on the noise, and to provide the control scheme more specifically, and how to accurately predict the noise in the product development stage, The NVH problem such as low-frequency sound-solid coupling noise in the vehicle is analyzed, and the main research direction of the major automobile manufacturers and research institutes has been made. In this paper, a set of theoretical methods and technical processes for fast and accurate prediction, analysis and control of low-frequency sound-solid coupling noise are established through the deep research on the transmission and analysis of low-frequency sound-solid coupling noise of a domestic light bus, and a set of theoretical methods and technical processes that can quickly and accurately predict, analyze and control the low-frequency sound-solid coupling noise are established. The analysis theory and method of TPA are enriched. In this paper, the research and control methods of low-frequency sound-solid coupling noise in the vehicle are summarized and analyzed, and the basic thinking of this paper is to study the acoustic-solid coupling noise based on the theory of transmission and analysis. In this paper, the theoretical basis of low-frequency sound-solid-coupled noise transmission and analysis is presented in this paper. The theory of transfer function and its unbiased estimation are derived, and three methods of working load identification and application range are introduced in detail. The process of using singular value decomposition method to solve the generalized inverse matrix is mainly derived. The analysis of single-reference transfer and the analysis of multi-reference transfer are introduced. The model of the low-frequency sound-solid coupling noise of the whole vehicle is established based on a domestic light bus. The model comprises a plurality of transmission paths which are supported by a power assembly, a front suspension, a rear suspension and a transmission shaft as an excitation end, and the human ear-ear-side noise is a response point. The low-frequency sound-solid coupling noise of the whole vehicle is analyzed based on this model. And the passive end working load of the elastic element is obtained by using the inverse matrix method. The vehicle NVH level analysis is briefly introduced for the target point data in the working condition test before the transfer analysis is carried out. By combining the subjective and objective data, the problem of noise in the position of the driver's ear and the position of the fifth row of passengers at 70 km/ h is determined, and the subjective feeling of the noise is described in detail. In view of the transmission and analysis of the main positions at the frequency of the working condition, a method for evaluating the contribution of the noise transmission path considering the sound pressure level, the amplitude and the phase is presented. The re-packet calculation is further performed for each suspension using this method. A preliminary determination is made of the paths that have a major impact on the different frequencies and the various locations. In order to analyze the mechanism and characteristics of low-frequency noise, an acoustic-solid-coupled finite element model, including vehicle body, frame, door and window, is established. The finite element modeling of the frame and the white body is established, and the modal frequencies of the simulation and the test are basically consistent and the mode shape is consistent. The finite element model of the window and the door is set up, and the whole vehicle model of the closed state of the door and window is obtained by using the correct connection and restraint. Based on the finite element model of the whole vehicle, the finite element model of the acoustic cavity of the seat in the vehicle is established. The acoustic-solid coupling model of the whole vehicle is further established, and the characteristics of the acoustic and structural modes before and after coupling are compared and analyzed. The material sound absorption characteristics and structural damping obtained by the test are applied to the coupling model. In order to verify the low-frequency sound-solid coupling model, the noise in the vehicle is mixed and transmitted and analyzed and compared with the results of the test transmission and analysis, and a more accurate low-frequency sound-solid coupling model is obtained. In order to further reflect the superiority of tpa in the analysis, prediction and application in the initial stage of R & D, the multi-body dynamics model of the whole vehicle with the running system and the b-level road surface is established, and the virtual tpa model of the vehicle sound-solid coupling noise is established by combining the model with the acoustic-solid coupling model. Based on the results of the analysis of the low-frequency sound-solid coupling noise, a comprehensive analysis method of the noise in the vehicle with multi-frequency, multi-response points and multi-working conditions is presented, and the comprehensive contribution is analyzed. The transmission path of low-frequency sound-solid coupling noise contribution to light passenger car is determined. Three tpa methods are analyzed from the three aspects of the theoretical basis, the analysis result, the following optimization and the like, and the superiority of the virtual tpa is proved. The single-stage and secondary transfer-level analysis is carried out for the path with the largest contribution. Through the analysis of single-stage transfer, it is determined that the transmission characteristic is the factor that needs to be optimized, and it is determined that the plate is the main link that needs to be optimized. In this paper, the secondary transmission and analysis of the plate link are carried out, and an algorithm for improving the acoustic contribution coefficient of the plate is proposed, which takes into account the multi-frequency, multi-response points, multi-working conditions and relative relation. Based on this method, the concept of the acoustic effect coefficient of the plate is further put forward, and its meaning is described. Based on the new algorithm and concept, an in-depth secondary transmission and noise reduction analysis is carried out. Based on the results of the analysis, the plate which needs to be controlled is finally determined, the damping noise reduction measures are implemented, and the noise reduction effect is verified by the method of simulation and test. It is proved that the series of theories and methods presented in this paper can be used to analyze, control and predict the low-frequency structure noise.
【学位授予单位】：吉林大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：U467.493

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