In order to improve the safety of the braking process of high-speed train, the brake disc heat dissipation structure needs to be optimized. The ANSYS-workbench software was used to establish a three-dimensional transient model. The temperature field simulation was performed on the brake discs with 8 different structural parameters based on the energy folding algorithm. The initial friction braking condition was obtained when the initial braking speed was 350 km/h. The change mechanism of the temperature field and the thermal stress field of the brake disc was analyzed by changing the height, the arrangement density and the discharge angle of the radiator. The simulation found that increasing the drainage angle, height of the heat dissipation ribs, and reducing the arrangement density can contribute to the heat dissipation of the brake disc; in the emergency braking project, the highest temperature point is on the brake disc surface, and the maximum thermal stress is on the side of the heat dissipation rib; In all 8 schemes, scheme 7 meets the braking requirements of high-speed trains with the initial speed of 350 km/h, the highest temperature is the lowest in all schemes, and the maximum thermal stress is reduced by 36 MPa.

针对无人驾驶方程式赛车对感知系统要求精准和实时性的特点,设计了一种基于激光雷达和相机信息融合的目标检测系统.建立了传感器感知模型,视觉信息采用YOLO v4图像识别算法,距离信息通过对点云的滤波、聚类获取,对点云的倾斜问题采用一种基于地面拟合的旋转处理算法进行校正,将图像坐标与点云坐标采用欧式距离策略进行目标信息融合.试验结果表明,雷达算法能够完成三维目标检测,YOLO v4图像识别算法对交通锥桶的检测平均精度为97.5％,u、v方向上的平均像素误差率在1％,目标检测系统在准确率、实时性方面达到实际行车要求.

利用数值仿真分析的方法,对3种散热筋结构制动盘在列车初速度为300 km/h匀减速制动时对流换热的温度场、流场以及平均对流换热系数进行了数值仿真分析,根据流场流线速度图和对流换热系数图,得到了制动盘平均对流换热系数和总热量随时间的变化规律.仿真分析表明:板型的通风筋比圆柱型散热效果好,交换的热量多.

为了研究列车盘式制动器的制动噪声特征,根据缩比原理分别制成摩擦盘和销的试样,使用UMT-5型摩擦磨损试验机做销-盘试验,通过采集并分析声音信号,利用有限元分析软件ABAQUS对试验结果做数值模拟.结果 表明:制动噪声的特征与试验开始时摩擦盘的转速(制动初速)以及施加在摩擦副接触界面上的载荷有关.“高转速、大载荷”条件下的噪声对人耳听力影响最大.摩擦副在试验过程中存在应力分布不均的情况,应力集中造成系统持续的自激振动,进而产生噪声.

为了研究盘式制动器在紧急制动工况下瞬态温度场的变化,利用Starccm+计算出的随转速变化的对流换热系数,使之与解析法对比验证。将其作为瞬态计算的边界条件,结合实测摩擦系数--车速试验数据,通过Abaqus分析制动盘径向、周向及轴向温度场、应力场的分布特性;通过台架试验与仿真结果对比,仿真温度与试验温度结果具有良好的一致性。研究结果表明:盘式制动器在制动过程中温度场及应力场存在复杂的耦合关系,建立CFD和CAE联合仿真模型可以为制动盘温度场的分析提供了一种有效方法。

利用摩擦磨损试验机(UMT-5)对铜基粉末冶金制动材料进行试验,得到不同制动速度、制动压力对铜基粉末冶金材料摩擦系数的影响以及摩擦材料的磨损量;利用ABAQUS建立试验过程摩擦材料仿真模型,通过仿真分析与试验结果进行比对,得到铜基粉末冶金材料温度及应力变化趋势.在相同工况情况下仿真结果与试验结果基本吻合,证明建立的摩擦制动仿真模型可靠有效.摩擦块温度场一直处于上升趋势.在制动速度为916 r/min时,高速列车摩擦块的摩擦系数较为稳定,且磨损量较小,因此应尽量在此速度下开始制动.

为了满足汽车动力学整车仿真的研究需要,基于Matlab/Simulink,用PAC2002魔术公式建立某轮胎动力学的仿真模型,对车辆稳态行驶时在轮胎纯驱动(制动)、纯转弯、驱动(制动)和转弯联合等工况下,分别进行纵向滑移率、侧偏角、垂直载荷等指标对纵向力、侧向力和回正力矩的仿真分析.仿真结果表明,基于PAC2002魔术公式的轮胎动力学模型能够比较准确地模拟出轮胎的动力学特性.

为探讨系统参数和结构特征对汽车制动过程中摩擦激励振动的影响,建立了通风盘式制动器10自由度动力学模型.利用ANSYS有限元软件识别了振动系统的刚度矩阵与质量矩阵等参数;采用Matlab/Simulink软件对方程进行求解;讨论了制动盘的弹性模量、摩擦系数以及厚度对制动盘法向振动和偏转振动的影响.实验结果表明,制动盘的厚度和弹性模量对其振幅、振动频率和衰减速度影响较大;摩擦系数变化对系统的振动无明显影响.

针对摩擦激励的盘式制动器振动问题,建立了6自由度非线性动力学模型.通过试验辨识了摩擦模型的系数.通过对动力学模型的求解绘制了摩擦片和制动盘振动的分岔图和频域图,探讨了制动速度、制动压力、制动盘刚度和摩擦片支撑刚度对系统振动特性的影响.研究表明,车辆在低速制动时,制动系统会出现丰富的非线性特性;制动压力是诱发非线性振动的主要影响因素;提高制动盘的刚度和制动片的支撑刚度都会降低系统振动的振幅度,但易激发摩擦片的高频振动.

为了分析制动器制动过程中温度、应力场的耦合情况,进行了台架试验.考虑摩擦副材料属性、摩擦系数随温度变化的特性,采用直接耦合的方法,同时利用有限元软件ABAQUS对制动工况进行模拟仿真.针对同一制动工况,试验与仿真分析的结果基本吻合,建立的仿真模型精确可靠.继而利用该模型进行紧急制动工况仿真,并对热机耦合关系进行分析.分析结果表明,温度场、应力场在制动过程中相互制约影响,总体均呈先增大后减小的变化趋势;制动过程中,制动压力并不是均匀分布的.

为解决某型重载卡车驱动桥使用寿命较短的问题,在进行试验场可靠性试验时测得了该车道路行驶工况下钢板弹簧对桥壳的动载荷和传动轴给主减速器的输入载荷,据此使用Romax软件建立了主减速器系统的动力学模型,得到了实际运行工况下主减速器轴承系统施加于桥壳的动载荷,然后使用Design Life疲劳分析软件对驱动桥壳在单独施加板簧载荷和同时施加板簧载荷与主减速器轴承载荷两种分析工况下的疲劳特性进行了分析计算,发现同时考虑板簧载荷和轴承载荷时的分析结果比较接近该车的实际寿命.

A new approach for the partial eigenvalue and eigenstructure assignment of undamped vibrating systems is developed. This approach deals with the constant output feedback control with the collocated actuator and sensor configuration, and the output matrix is also considered as a design parameter. It only needs those few eigenpairs to be assigned as well as mass and stiffness matrices of the open-loop vibration system and is easy to implement. In addition, this approach preserves symmetry of the systems. Numerical example demonstrates the effectiveness and accuracy of the proposed approach.

为了研究排气消声器内部声场对消声器结构的影响，掌握消声器系统耦合特性，建立了消声器的声振耦合模型，对耦合系统中消声器壁板在声场影响下的振动位移进行分析。发现高频时，声场作用对结构振动位移的影响较大，特别是90Hz频率附近消声器壁的位移响应明显，影响消声器系统性能。为了保证消声单元性能的稳定性，以减小振动位移响应量为目标，对消声器结构进行改进，使得消声器壁板的振动位移减小，并使最大位移振动频段避开了激励频段。

To study the dynamic characteristics of the heavy vehicle brake system,a three-dimensional finite element model established based on ABAQUS and Hyper- Mesh software. The stress and strain calculated and the distribution of drum,shoes and linings are obtained. It is verified by the break test results in Xiangyang Automotive Proving Ground. Then the modal analysis of drum brake system is performed. The first 16th principal vibration modals and frequencies are also gained. These achievements have practical engineering significances in drum brake products development.

To reveal the muffler acoustic performances and structure vibration characteristics, the computational fluid dynamical (CFD) model and finite element method (FEM) model were established. Acoustic analysis results show that the muffler not only has complex acoustic vibration modes, but also the mode frequency approximately equals the engine’s incentive frequency at rated speed, so the resonance may occur and the noise eliminating effect will be reduced. Structure vibration modal analysis shows that the muffler system has high natural frequency and the natural frequency is widely distributed. So while the engine runs at rated speed or idling speed, its natural frequencies are close to the engine exhausting incentive frequencies. It is the main cause that the muffler cannot reduce the noise effectively and needs further optimization.

To evaluate the applicability of different constitutive models for chloroprene rubber boot,the finite element models of rubber boot and rubber material specimen are established by the HyperMesh and ABAQUS software.According to the uniaxial tension test,a series of rubber characteristic parameters,based on MooneyRivlin,Ogden as well as Yeoh constitutive models,are obtained through ABAQUS by fitting data.Then the finite element results for specimen and rubber boots of axial tension and compression under different working conditions are obtained.The comparison between the experiment and the finite element analysis shows that two coeffcients of the Mooney-Rivlin model are very accurate when the tensile rate is not more than 100%.But if the tensile rates exceed 100%,the Yeoh and Ogden constitutive model yields more accurate results.

To reveal the relationship among the parameters structure and the extension and compression performance,a rubber boot finite element analysis model was established which based on the Mooney-Rivlin constitutive model by ABAQUS software.Then the constitutive parameters C10 and C01 were got by using data curve fitting methods of the standard rubber specimen experimental.The extension and compression simulation was achieved,the deformation and strength of rubber boot are computed.The tension test both sample and rubber boot demonstrated that the finite element analysis is reliable.It presents an approach to analyze the strength and optimize the structure parameters for rubber material components.

The vibration and noise problem is an important factor affecting the vehicle riding comfort. When the vehicle is traveling,the tire-road noise,wind noise and noise generated by power system are inevitably transmitted to the vehicle interior. To improve the riding comfort of the driver and reduce the noise of the car pass-by,GMT material was used to make protection plate which was installed at the car chassis cover. Two kinds of chassis protection plate cover programs were propose by which noise could be absorbed. A system model to control the overall noise was established to reduce interior noise and pass-by noise. Overall design program and relevant factors should be taken into account were analyzed.

In order to solve the problem of incomplete model in the research about heavy truck drive axle,a complete coupled model of drive axle is established by Romax( RomaxDesigner) software in this paper,and the simulation results are displayed. The comparison with non-coupled model in bearing damage,shaft deformation and modal proves that the coupled model is more real and effective,providing a new and effective method for the research of drive axle.