【作者】 左言言；

【导师】 耿烽；

【作者基本信息】 江苏大学 ， 车辆工程， 2011， 博士

【摘要】 城市轨道交通车辆车内噪声直接影响旅客乘坐舒适性,也是反映车辆品质的重要指标。预测客室内部噪声获得车内噪声产生机理以及车内噪声声场特性,可以合理地指导车体结构设计及车内声学空间优化,实现车内噪声控制,满足旅客乘坐舒适性要求。随着中国城市轨道交通车辆的国产化程度日益增高,城市轨道交通车辆车内噪声预测与控制,对车辆的设计、制造、运营等多方面具有着重要的实际意义和应用价值。关于城市轨道车辆客室噪声预测与控制方面的研究,目前国内尚处于起步阶段。随着轨道车辆轻量化设计的要求,大型中空挤压铝合金型材成为城市轨道车辆车体结构材料的主要选择。纵观目前国内关于铝合金型材构成车体结构的铝合金城市轨道车辆车内噪声特性预测分析方面的研究,相关成果尚无报道。因此借鉴汽车车内噪声特性预测分析手段,以铝合金A型地铁车辆为研究对象,利用有限元方法结合边界元方法数值预测了轨道随机不平顺激励下车内结构噪声特性,并且在城市轨道交通运营企业现场实测了相同车型车内噪声特性,验证预测结果。进一步利用声传递向量法找到并修改对车内噪声贡献较大的车体结构以实施车内噪声控制。进而采用Zwicker法进行了车内噪声预测结果的心理声学响度参数计算,并比较了车内噪声A计权声压级与响度两种评价方法的区别,为获得更为符合人体心理主观感受的车内噪声特性提供控制目标。整个研究比较全面地实现了铝合金地铁车辆客室内部低频结构噪声的预测分析,补充了国内现有轨道交通车辆噪声的研究成果,拓宽了运用有限元结合边界元方法预测车辆内部噪声的应用领域。并且将心理声学响度参数噪声分析方法应用于地铁车辆车内噪声的评价。整个研究具有一定的创新性和前瞻性,必然对降低铝合金地铁车内噪声和车体低噪声设计具有指导作用。通过仔细提取铝合金地铁车辆车体结构特征,构建车体结构有限元模型并计算其静、动态特性,结果验证了建模的准确性。进一步建立车内空间声场模型以及车体结构与车内声场耦合模型,依据结构、声学和声固耦合系统模态理论,分析了车体结构的模态频率和变形、车内声学系统的声学模态频率和声压分布,以及声固耦合系统中车体结构和车内声场的模态频率和振型变化,结果说明了车体结构与车内声场具有较强的相关性。建立地铁车辆—轨道耦合动力学仿真模型,进行了整个地铁车辆系统动力学分析。车体振动加速度仿真结果与相同车型地铁车辆振动加速度现场实测结果比较发现,二者吻合较好,验证了所构造的动力学仿真模型的准确性,为准确得到轨道随机不平顺激励下车体所受动态载荷仿真计算结果奠定了基础。将车体所受动态载荷施加于车体结构相应位置,利用有限无谐响应分析方法,计算得到车体结构在轨道随机不平顺激励下车体结构振动响应。将车体结构振动响应作为边界条件传递给车内声场边界元模型,仿真预测车体结构振动响应所形成的车内结构噪声特性。结果表明影响车内结构噪声的因素主要为车体结构特点、激励载荷情况以及车体壁板的振动响应特性。将车内噪声仿真结果与相同车型地铁车辆车内噪声现场实际测量结果进行比较,发现二者声压分布规律基本一致,均反映出车内噪声能量主要分布在中低频范围,低频噪声成分尤为突出。比较结果也说明噪声预测结果具有较高的可信度,整个仿真计算过程切实可靠。在此基础上利用声传递向量方法进行车体结构壁板的声学贡献度分析,找到车体结构振动中对车内噪声贡献较大的区域并修改车体结构后,结果表明车内噪声降低效果明显。最后采用Zwicker法编程计算了车内噪声仿真预测结果的特性响度,比较了A计权声压级与响度两种评价方法的区别。结果发现,车体结构修改后,虽然A计权声压级评价表明车内声压级整体降低明显,但是响度评价说明噪声降低主要集中在100 Hz以下,而对人耳更为敏感的150—350 Hz频段的噪声衰减相对较弱。因此应该着力降低1-5 Bark临界频带上的噪声能量,以使车内声场获得更好的主观听觉效果。研究过程和研究结果表明运用有限元结合边界元方法预测轨道随机不平顺激励下铝合金地铁车辆客室内部低频结构噪声特性行之有效。声传递向量方法适合指导地铁车辆车体结构改进以达到降低车内噪声目的。心理声学参数评价地铁车辆客室内部噪声可以为车内噪声品质改善提供控制目标。研究结果不但可以为城市轨道交通车辆车体结构低噪声设计提供依据,同时可以为车辆系统动力学性能改善提供参考。另外也可以为相似车体结构车辆的车内噪声预测分析与控制提供借鉴。更多还原

【Abstract】 The interior noise of urban rail transit (URT) vehicle has direct influences on the passengers’riding comfortability, and is an important parameter of vehicle quality as well. The interior noise prediction can conduct car body structural design and internal acoustic space optimization by acquiring noise-produced mechanisms and sound field characteristics, so that the internal noise of car could be abated in order to satisfy the request of passengers’comfort. With the currently growing numbers of China-made parts in URT vehicle, it is being presented the momentous practical significance and applied value of the interior noise prediction and the control on car-body’s design, manufacture, operation, and so on.In China the prediction research and control for URT vehicle interior noise is now just at the stage of beginning. With the lightweight demand of rail vehicle, the aluminum-alloy hollow extrusion bases have been commonly chosen as the structural materials to use on the car body of URT vehicle. In respect that current domestic researches have not conducted relevant results to cover the inner noise characteristic prediction and analysis for alloy aluminum body-framed coach, this work was specifically concentrated on the A-type aluminum alloy metro vehicles. Accordingly the analysis methods applied to automobile, the car’s inner structural noise characteristic under irregular track actuation was numerically projected by the finite element method (FEM) and the boundary element method (BEM) integrated. And the interior noise properties of the coaches with same structural frames were measured to validate the predicted results at the operation sites of urban rail transportation enterprises. The further research has revealed the body structure with large proportions of interior noise by applying the acoustic transfer vector (ATV) method so that the car body’s inner noise could be controlled through the structure improvement. Other approach, Zwicker Method, was be used to have the parameter computation of psychoacoustical loudness to correspond with the car’s interior noise prognostication. The two appraisement methods, the A-weighted sound-pressure level and the psychoacoustical loudness, are contrasted in order to find the controlling targets of the interior noise, which are much similar to human body’s psychological feeling.The whole study broadly has fulfilled the predicting analysis to the internal low-frequency structural noise of the aluminum-alloyed metro coach. The project also provides dozens of new achievements for the domestic rail vehicle’s interference research, and further develops wide areas of FEM and BEM applied to the prediction of car body’s interior noise. Besides, the psychoacoustical loudness-based noise parameter analysis method is used to evaluate the car’s inner noise of metro. This research work represents its innovative and foreseeing, and must take a guidable function for the coming research activities of the interior noise reduction on the alloy aluminum metro and the low-noise design of body.Carefully extracting the structural features, the finite element model of aluminum alloy metro car body was established. Based on the model, the calculations of both static and dynamic parameters were furthered, and the modeled accuracy was examined. Subsequent research models were constructed, for example, the sound-field model facing car’s interior space, and the systematical coupled model between body structure and internal sound field. Based on vehicle structures, acoustics and acoustic-structure coupling system modes, the mode frequency and deformation of the geometric structure, the acoustic mode frequency and sound-pressure distribution of the inner acoustic systems, as well as the changes of the mode frequency and vibrant type for the structure and the car’s interior sound-field in acoustic-structure coupling systems were investigated and simulated. As a result, the analysis showed the marked correlativity between the body structure and the sound field.The kinetic analysis for the integrated metro system was performed on the established modal of vehicle-track coupled dynamic simulation. The comparisons between the car body’s acceleration-oscillated simulations and the acceleration-oscillated field-tests to the homogeneous metro trains show that the results of both have rather consistent, which depicts a sound accuracy of the established dynamic simulation modal. The works make a foundation that exactly accomplishes the dynamic body-loaded simulation and computation under the random irregular track actuating oscillation.Applying the dynamic loads on the involved positions of the body structure and using the finite element harmonic response analysis method, the calculated results presented the body structure’s vibration responses under the random irregular rail-track actuations. The body-structured vibration responses then was used as the boundary conditions to transfer to the boundary element models of the car’s interior sound field so that it could be simulated and taken a prediction about the inner structural noise characteristics produced by the responses. The simulated results indicate that the major impact factors of internal structural noise include the property of car body structure, the status of actuating loads, and the oscillation response particularities of body walls. Comparing the interior noise’s simulation results of models and the field-testing results of homogeneous metro coaches shows that the sound-pressure distributions of both are basically consistent. Moreover, all of the outcomes reflect that the car’s interior noise energy mainly distributes in the range of intermediate-and low-frequency, especially having an obvious component of low frequency. Besides, the contrasting results also represent the high reliability of noise projections, or the entire simulating and computing processes are reliable. Depending on the acquired foundations, the acoustic contribution-ability analysis method alongside the application of the acoustic transfer vector (ATV) method for the car body’s structure hoods gave an approach to locate places in which the considerably participative inner noise was caused by body’s structural vibration, and an instruction to improve body structures. As a result, it has an evident effect on the car’s interior noise reduction.As one of the ultimate productions, the particularity loudness in simulating prediction was completed by the Zwicker’s computation-programmed method, and the differences of two appraisement methods, the A-level weighted sound-pressure and the loudness, had been compared. After the modification to the car body structure was done, the A-level weighted sound-pressure evaluation showed an evident entire decrease in the car’s interior sound-pressure degree. However, the loudness appraisement approach indicated that the noise reduction was mainly distributed in the range below 100 Hz, while this frequency section of noise from 150 to 350 Hz, which is more sensitive to the human ears, had only relatively little attenuation. Therefore, the noise resistance should be concentrated on the noise energy reduction at the critical frequency band of Bark 1-5, so that there is an easier subjective aural feeling in the coach’s sound field.The research process and final represented facts show that it is effective to predict the car body’s interior low-frequency structural noise characteristics of aluminum alloy metro under random irregular rail-track actuations by combining FEM and BEM. Secondly, the ATV method is suitable to direct the improvement design for body structure to achieve the inner noise reduction. Furthermore, the psychoacoustical parameter analysis can be used to evaluate the interior noise of metro vehicle, thus to provide the noise abatement-controlled aims and improve internal sound quality of the car. The whole investigation may not pay only the scientific basis for the car-body structure low-noise design of URT vehicle, but contribute the improvement instructions for the dynamic performances of vehicle systems. In addition, the study of the project is also references to the prediction analysis and the control for the interior noise of similar car-structures.更多还原