汽车制动盘热翘曲与影响因素仿真分析

为研究汽车通风盘式制动器的制动盘热翘曲及其主要影响因素,利用MSC.marc软件建立了盘式制动器有限元瞬态热机耦合动力学仿真模型。在验证了模型有效性的基础上,系统分析了制动盘帽部的热传导和机械约束的作用以及制动盘壁厚差等关键结构参数对翘曲方向与翘曲量的影响。分析表明,制动盘帽部机械约束和壁厚差是影响制动盘热翘曲的主要因素。     

气流方向对通风制动盘散热性能的影响

制动盘温度过高会使汽车制动性能下降,研究冷却气流的方向对制动盘散热性能的影响,对加强制动盘的对流换热性能有着重要意义。在Fluent软件中仿真计算了实心制动盘,直方肋板通风制动盘,正旋和反旋的弯曲肋板通风制动盘模型,得到了各制动盘在不同来流方向下的外流场、外温度场、表面对流换热系数以及散热功率,确定了制动盘内侧沿中心轴的来流方向使制动盘散热最优,而沿制动盘径向的来流方向对制动盘的散热性能影响较小。在设计汽车制动盘对流冷却机构时可以参考这一结果。     

初始厚薄差对制动器热机耦合特性的影响

为研究制动盘初始厚薄差对制动器热机耦合特性的影响,建立了具有初始厚薄差的通风盘式制动器瞬态热机耦合模型,对比分析了初始厚薄差最大值及其方向对盘面温度、法向应力、热弹性变形的分布特性及特征值的影响。研究结果表明,初始厚薄差使盘面温度、法向应力和厚度变化在圆周内均呈现出显著的2阶正弦特征,周向梯度增大,径向分布趋于均匀。     

基于Optistruct的汽车制动盘防尘罩形貌优化

汽车制动盘防护罩的结构强度和刚度不足将对汽车行车安全构成隐患。利用HyperWorks软件建立某汽车制动盘防尘罩的有限元模型并进行模态分析,根据模态分析结果,以提高制动盘防尘罩的结构固有频率为优化目标,在OptiStruct模块中对防尘罩外壳进行形貌优化,结合冲压制造工艺,设计加强筋的最佳布置方案,并对优化方案进行验证。结果表明,优化后的防尘罩第1阶固有频率提高,优化效果明显,满足设计要求。最后通过算例对加强筋高度、宽度、起筋角进行参数化运算,得出加强筋参数对于薄壁钣金件结构强度的影响规律。     

盘式制动器的热力学耦合分析

制动器是汽车的重要组成部分，对盘式制动器来讲，制动盘散热性能的好坏直接影响着制动器的安全性。通过设计一款制动盘的参数并建立其三维模型，在ANSYS的基础上，使用耦合场瞬态分析模块对建立的三维模型进行热耦合分析，得到刹车后制动盘温度随时间的变化云图。热耦合分析结果表明，刹车后该设计制动盘的温度变化及分布规律是合理的，研究结论为制动盘的进一步优化设计提供参考意义。     

基于响应面法的某乘用车制动盘模态优化设计

为了得到满足模态分离且质量轻的乘用车制动盘结构,同时也为乘用车制动盘的模态优化设计开发提供理论依据,以某乘用车制动盘为研究对象,创建某乘用车制动盘的模态有限元仿真分析模型,将某乘用车制动盘的结构参数作为制动盘模态优化的设计变量,通过可扩展的格栅序列法进行试验设计,使用克里格法进行某乘用车制动盘模态响应面分析模型的创建,再采用遗传算法对某乘用车制动盘模态响应面分析模型进行优化。结果表明,基于响应面优化法获得的某乘用车制动盘满足模态分离要求,优化后的质量为8.114 8 kg,优化前的质量为9.739 kg,优化后的质量减轻了约16.68%,轻量化效果显著。     

PHEV电池包热管理系统设计优化与仿真分析

为实现电池包热管理系统低能耗和高效率散热的目的,文章通过流体动力学（CFD）仿真及实验对某插电式混合动力汽车（PHEV）乘用车电池包热管理系统进行优化研究。电池包热管理系统采用液冷散热,流场压力损失设计目标值为27kPa。初始方案中,流场压力损失实测值约为60 kPa,CFD仿真分析表明,液冷系统流场进出口是产生压力损失的主要部件;采用增大进出口管径的方法对液冷系统进行优化,仿真和实验结果表明,优化后的液冷系统压力损失减小至26 kPa左右;液冷系统流场优化后,对电池包散热特性进行仿真和实验分析,结果表明,在67.6 kW工况下电池包最高温度为53.2℃,低于目标值55℃。综合分析可以得出结论,优化后的电池包液冷系统各项指标达到目标状态。     

浅谈摩托车制动盘热变形

制动盘是摩托车制动系统关键、核心部件。制动盘质量问题涉及到整车行驶安全、操控舒适性等多个方面。车辆行驶在不同路况下使用制动器的频率和制动效果强弱的不同,以及摩擦片材料和制动盘散热结构的不同等诸多因素导致制动盘的工作条件非常复杂。而且摩托车制动盘通常用3～6 mm不锈钢冷轧薄钢板制造,在市场上摩托车制动盘受热变形时有发生,造成安全隐患及市场投诉。故对制动盘热变形分析,找出制动盘热变形基本原理方向,对新设计、改进提升制动盘质量具有重要的现实指导意义。     

雪峰山隧道通风数值模拟研究

介绍了网络通风系统仿真软件，对单座斜井送排式通风方案和左右洞三斜（竖）井联合送排式通风方案进行了通风数值模拟计算，并对两方案进行了比较分析。     

电动赛车电池箱通风冷却结构设计方法及应用

为解决严重影响电动赛车性能的电池箱通风冷却结构复杂、质量重及散热速度缓慢等问题,采用以空气为介质的电池箱通风冷却结构先确定散热器的性能参数,并结合流体仿真分析软件(Fluent)模拟电动赛车的行驶工况,从而有效地优化电池箱通风冷却结构.采用该结构的电动赛车参加了2013年首届中国大学生方程式电车大赛(简称FSEC),顺利完成所有比赛项目并获得全国总成绩第2名.结果表明,此结构仿真分析与实际运用基本吻合.     

Analysis of automotive disc brake squeal considering damping and design modifications for pads and a disc

The squeal noise occurring from the disc brakes of passenger cars has been analyzed by using the complex eigenvalue method numerically. The contact between a disc and two pads was analytically modeled as many linear springs and dampers in an effort to develop the improved equation of motion derived on the basis of Lagrange’s equation and the assumed mode method. The finite element modal analysis results for disc brake components constitute an eigenvalue matrix in the analytical equation of motion. The complex eigenvalue analyses based on the equations of motion are able to examine the dynamic instability of a brake system, which is an onset of squeal, by considering the disc rotational effect. Numerical analyses showed that the modes unstable in an undamped analysis became stable in a damped case, which illustrates the important effect of damping on the squeal instability in a brake squeal simulation. Then several modified brake models were suggested and investigated how effectively they suppressed the occurrence of squeal noise. The brake parts such as a pad chamfer and a disc vane were modified and the influence of pad chamfer and vane shapes on squeal occurrence was proved to be significant. The numerical results showed that proper structural modification of a disc brake system can suppress the brake squeal to some extent.     

Investigation of influential factors of a brake corner system to reduce brake torque variation

This paper investigates the brake corner system to reduce brake torque variation in the brake judder problem. A numerical model for determining brake torque variation was constructed using the multi-body dynamics model. Using this model, the brake torque variation for a given disc thickness variation was obtained in the time domain. The multi-body dynamics model was verified by a dynamometer test via the comparison of brake torque variation and load distribution patterns of the pad. To reduce the simulation time and cost required to determine factors that influence the reduction in brake torque variation, a simple mathematical model was constructed and used to determine both the brake torque variation and influential factors. The multi-body dynamics model and dynamometer test were modified on the basis of the results of the simple mathematical model and deformed shape of the multi-body dynamics model. These influential factors were verified to reduce the brake torque variation.     

Analysis of disc brake instability due to friction-induced vibration using a distributed parameter model

This paper deals with friction-induced vibration of a disc brake system with a constant friction coefficient. A linear, lumped, and distributed parameter model to represent the floating caliper disc brake system is proposed. The complex eigenvalues are used to investigate the dynamic stability, and, in order to verify simulations which are based on the theoretical model, an experimental modal test and dynamometer test are performed. The comparison of experimental and theoretical results shows good agreement, and the analysis indicates that modal coupling due to friction forces is responsible for disc brake squeal. Also, squeal type instability is investigated, using a parametric analysis. This indicates which parameters have influence on the propensity of brake squealing. This is helpful for validating the analysis model and establishing confidence in the experimental results of the modified system. These results may also be useful during system development or diagnostic analysis.     

Measurement of the disc-pad friction coefficient for mechanical brakes using direct and indirect methods

It is necessary to guarantee the proper brake force to stop a train safely in a limited distance and o adjust its speed. Currently, most trains are run by electrical power and have a combined electrical and mechanical (friction) braking system. The mechanical brake force is determined by many parameters, such as the friction coefficient of the brake disc and pad, the pressure in the brake cylinder, the brake cylinder’s cross sectional area and the brake linkage ratio. In general, the friction coefficient data of the brake disc and pad have been taken through a dynamo-test in a laboratory, but these data might not be well matched with real data under operating conditions because of the difference in data acquisition conditions. The present study examined two methodologies that can measure the friction coefficient of the brake pad and disc based on a train’s real operating conditions. The first method was the direct method, which measured the brake force and clamping force applied on the mechanical brake by using strain gauges installed on the brake to calculate the friction coefficient. The second was an indirect method that obtained the friction coefficient by using the weight of the train and the equivalent brake force. Those variables were calculated from the longitudinal dynamic characteristics, such as resistance to motion, gradient resistance and curved resistance. These two methodologies were used to obtain the disc-pad friction coefficient for the mechanical brakes of a Korean high-speed train (HSR350x).     

平地机湿式制动设计

由于湿式制动具有制动平顺、磨损轻、散热快、使用寿命长、节能环保的特点,故近年来在国外大型工程机械上得到广泛应用,并成为轮式工程机械制动系统的发展方向。介绍了一种满足CE要求的带湿式制动的平地机的设计,并详细讨论了行车制动湿式制动器的设计计算。     

浅述气压盘式制动器在城市客车上应用的可能性与可行性

分析了气压盘式制动器在城市客车上应用的可能性与可行性,重点论述了5．5T盘式制动器前桥的开发,并对盘式制动器前桥与鼓式制动器前桥的制动力矩进行对比计算。     

Experimental investigation using CFD for thermal performance of ventilated disc brake rotor

In the present work, different ventilated disc brake rotor configurations were analysed to enhance the heat transfer rate and obtain the uniform temperature distribution in the rotor. CFD code used in this work was validated at using experimental results obtained by conducting experiments on a test rig. The experimental analysis was performed to calculate the mass flow rate and heat dissipation through the rotor. Further, different types of rotor configurations viz. straight radial vane (SRV), tapered radial vane (TRV), alternate long and short vane (ALSV), variable diameter circular pillars (VDCP) were considered for the analysis. A rotor segment of 20° was considered for the numerical analysis due to its rotational symmetry. CFD results were in good agreement with the experiments. The maximum deviation of the numerical results were about 12 % from the experimental results. It is found from the analysis that among the different types of rotor configurations; variable diameter circular pillars (VDCP) rotor gives better rate of heat dissipation with more uniform temperature distribution in the flow passages. Hence for modern high speed vehicles VDCP rotor may be more appropriate.     

盘式制动器15次循环制动温度计算

本文针对盘式制动器，提出了15次循环制动的温升热力学模型，并利用有限差分法进行了实车计算，结果表明方法是可行的，可为制动器与整车的匹配设计提供参考。     

汽车气压盘式制动器的结构特点与性能分析

介绍了几种国内外重型汽车气压盘式制动器的结构及其特点,从左右轮制动力差异,制动器的效能因数与摩擦系数的关系及迟滞量等方面对盘式制动器与鼓式制动器进行性能对比分析,说明盘式制动器在制动效能、制动效能的稳定性以及制动时汽车的方向稳定性上比鼓式制动器具有明显的优势,理论和试验表明盘式制动器与ABS、ASR、EBS等系统匹配时可简化系统结构、优化系统性能,并对重型汽车装用盘式制动器带来的制动系统的相关问题进行了探讨.     

Prediction of the cooling factors of a vehicle brake disc and its influence on the results of a thermal numerical simulation

In the process of developing the brake disc, it is necessary that we predict the suitability of the design. In this manner, we can affirm that even the first prototype will satisfy all of the customer homologation requests. Usually those comprise different sequential braking tests in which the maximal achieved temperature is the criterion that governs brake disc suitability. The knowledge of how to predict the behavior of a brake disc in the early pretesting phase has a significant impact on development costs and time. The common method that is used for predicting the temperatures in the brake disc during braking is numerical simulation analysis. With the help of Computational Fluid Dynamics, the flow through a vehicle ventilated brake disc of known geometry was determined, and the wall heat transfer coefficients for all vehicle speeds and brake disc temperatures were calculated. The results were then imported into a thermal numerical simulation of a sequential-braking vehicle test. The results showed that the consideration of cooling factors has a significant impact on temperature courses. To obtain accurate results from the numerical simulation and to simulate the vehicle test precisely, the proper wall heat transfer coefficients must be considered. The proposed method produces more accurate numerical results and enables the development engineer to develop suitable brake disc geometry in the early pretesting phase.