A material and gauge thickness sensitivity analysis on the NVH and crashworthiness of automotive instrument panel support

This paper provides a finite element analysis of the effects of using alternative materials and gauge thickness on the weight and structural performance of the VN127 instrument panel support. Two types of analyses were performed, NVH and crashworthiness. The NVH analysis was used to determine the structure’s natural frequencies, whereas the crashworthiness analysis was used to examine the structure’s crash behavior under two different impact conditions. The materials used in this study included mild steel, aluminum and magnesium alloys. The thickness of the structure was varied from 0% to 40%, in increments of 10%. The results of different models were compared with the baseline model, i.e., the mild steel model with nominal thickness. It was found that by replacing mild steel with aluminum alloys, and increasing the gauge thickness of the structure by 40%, the NVH and crashworthiness performance of the structure was equivalent to the baseline model.     

汽车进气系统声学模态仿真和试验

针对汽车进气系统噪声对整车NVH性能有较大影响的问题,通过与理论解的对比验证直管声学模态的仿真方法和试验方法的可行性.对进气系统进行声学模态CAE仿真,并设计一系列试验,逐级排查出CAE仿真与试验有差距的原因.根据算例的声学模态分析结果对进气系统消声元件位置的确定给出建议.     

Multidisciplinary optimization of car bodies

Rising complexity of industrial development in the automotive industry is leading to a higher degree of interdisciplinarity, which is especially true in the virtual design area. New methods and solution procedures have to be evaluated and integrated in the overall process. For example, in car body design process, a new topic emerged recently: the multidisciplinary optimization of car bodies with respect to crash and NVH (noise, vibration, and harshness). Because rigorous evaluation of appropriate numerical algorithms is still missing, an intense study was realized at the research center of BMW. The results are summarized in this article. Four benchmarks have been studied: (a) a full vehicle model for NVH analysis, (b) a simplified multidisciplinary problem with a single crash case and linear statics and dynamics, (c) a lateral impact problem for multi-criteria optimization, and finally, (d) a small shape optimization problem was included to demonstrate the potential of transferring the results to the more complex problem of optimizations based on real changes in the shape of the structures. Because response surface methods have already been discussed in the literature and because of their failure in certain industrial cases, the focus was set on the evaluation of stochastic algorithms: simulated annealing, genetic and evolutionary algorithms were tested. Finally, a complete industrial multidisciplinary example from the current development process was studied for the validation of the results.     

基于刚柔耦合模型的悬架NVH性能研究

使用有限元软件分析了橡胶衬套对悬架NVH性能的影响。柔化其他悬架部件,建立了多体动力学刚柔耦合模型。通过试验设计(DOE)分析了橡胶衬套刚度对悬架NVH性能的灵敏度并进行了优化。通过对比优化前后仿真结果,可以看出悬架中高频NVH性能得到了改善。将模型仿真与道路模拟机测试结果进行对比,验证了模型的准确性。     

商用电动车用永磁同步电机电磁振动噪声削弱方法

电磁振动噪声是电机振动噪声的主要噪声源,直接影响电机的NVH特性,而电磁力是影响电磁振动噪声的主要原因。本文基于解析推导法和Ansys多物理仿真平台,针对一台250 kW的商用电动车用永磁同步电机进行研究并对其电磁振动进行了分析,指出电机气隙磁密的变化将会影响电机定子齿受到的电磁力,从而影响电磁振动噪声。本文提出了一种通过在转子表面增加凹口的转子结构改进方案以削弱电磁振动噪声,并对改进前后电机的电磁、模态、振动、噪声进行仿真计算与对比分析。经过对比优化前后的分析结果可知,优化后的电机方案在保证平均转矩基本不变的前提下,转矩脉动得到降低,电磁振动噪声得到削弱。     

燃油系统旋涡泵压力脉动的控制研究

为了改善燃油泵噪声、振动、声振粗糙度(noise,vibration and harshness,NVH)性能,提高燃油泵声音品质,开展了燃油系统旋涡泵压力脉动的控制研究。采用计算流体动力学(Computational Fluid Dynamics,CFD)数值模拟方法和理论分析方法分析燃油系统微型旋涡泵的压力脉动特性,并采用随机叶片分布方法设计了2种非均布程度不同的非等距叶轮。基于CFD数值模拟结果和理论分析结果,提出一种改进的非等距叶轮设计方法。燃油泵噪声试验结果验证了该设计与控制方案的可行性。结果显示:相较于等距叶轮,随机非等距叶轮燃油泵的中高频段尖锐噪声消失,NVH性能提升;随机非等距叶轮能够显著分散叶频峰值,非均布程度的增加显著增大了随机非等距叶轮的叶频脉动幅值下降幅度。因此,采用随机叶片分布方法,有助于改善旋涡泵的压力脉动特性,对改善燃油泵的NVH性能具有重要的工程应用价值。     

汽车NVH试验数据管理系统关键技术研究

实现试验数据的有效管理和数据重用并形成NVH试验历史支撑数据库,成为支撑NVH研究、提高NVH研究水平的迫切需要。在分析了汽车NVH试验数据特点和试验数据管理需求的基础上,提出了一套完整的支持商用测试系统和手工数据的汽车NVH试验数据结构化方法,针对数据单位统一定义、数据可视化、试验对象动态扩展等关键问题提出了解决方案,并开发了实用化的汽车NVH试验数据管理系统。对提高汽车NVH研究水平和工作效率、减少工程试验成本上有重要作用。这些解决方案也可供其他振动噪声工程或汽车工程试验数据的系统开发参考借鉴。     

某轿车前副车架模态分析与优化

以"某车型前副车架"为研究对象,利用Hyper works 11.0软件对该副车架结构进行了自由模态分析、 全约束模态分析和半刚性约束模态分析,针对分析结果与实际整车下的模态值比较,提出了较为合理的边界约束条件下的模态分析方法,以更加接近副车架在整车下的实际状态值.同时由于该副车架整车实测模态值偏低,与发动机常用转速下...     

两用燃料汽车的振动噪声特性

试验研究了捷达LPG／汽油两用燃料汽车的振动噪声特性。主要测量了发动机缸体和座椅的振动情况，对比分析了匀速和加速时燃用汽油和LPG的噪声特性。试验结果表明：两用燃料汽车使用LPG时，发动机机体振动幅值比使用汽油时小；而加速过程中，在较低转速下使用汽油噪声较大，在较高转速下使用LPG噪声较大。     

提高SUV整车NVH性能研究初探

随着人们环保意识的增强,政府法规对噪声限值的要求越来越严格,用户对汽车舒适性要求越来越高。汽车振动噪声NVH性能已成为汽车市场竞争的重要方面和汽车产品未来的发展趋势。针对SUV车配备不同型式的柴油机、汽油机动力,以及四驱和二驱的不同传动形式开展了一系列NVH性能的研究工作,主要包括：动力总成悬置系统解耦及优化设计、改善隔振性能,降低车内结构振动噪声;车辆主要零部件的模态测试分析、模态分离,改善车内共振噪声;声学包装的合理应用以及进排气系统综合改进,从而大幅度减小车内噪声以及车外加速通过噪声。使SUV整车的NVH综合性能指标达到同类车型的先进水平。