车轮踏面制动的热-机耦合数值模拟

重载列车车轮踏面制动是一个复杂的动态接触热-机耦合问题,介绍了热-机耦合问题的求解方法,并利用有限元分析软件ANSYS对提速货车的单闸瓦踏面制动过程进行了紧急制动工况的数值仿真,定量地给出了车轮踏面温度和应力随时间的变化规律,为研究车轮踏面热疲劳提供了理论依据.     

汽车急转侧滑的预测控制原理

预测控制原理以ABS系统为基础,通过实时检测汽车行驶车速、车轮转动角速度和转向盘转角信号来预测汽车急转向时的状态,对汽车的个别车轮主动施加大小不同的制动力,以产生一个与横摆力矩相平衡的反作用力矩,防止汽车产生急转侧滑现象,同时提高汽车急转向时的操纵稳定性,对减少道路交通事故的发生具有十分重要的意义。     

液压制动管路整车布置设计

制动管路整车布置设计是汽车制动管路设计开发过程中关键环节。结合液压制动管路整车布置方案,介绍了液压制动管路(包括制动硬管和软管)的整车布置设计要求,并分析了制动管路布置设计对制动系统的影响,有利于指导制动管路的设计开发。     

Performance assessment of hybrid composite friction materials based on flyash–rock fibre combination

Friction composites based on several combinations of flyash and inorganic mineral rock fibres such as lapinus™ fibre were fabricated, characterised and tribo-evaluated. The tribo-performance in terms of their friction-fade and friction-recovery behaviour has been rigorously evaluated while synchronously taking into account of the in situ braking induced temperature rise in the disc at the braking interface on a Krauss friction testing machine following pulse velocity wave (PVW) 3212 norms as per the Economic Commission for Europe (ECE) regulations. The fade behaviour has been observed to be highly dependent on the combination of flyash–lapinus fibre e.g. fade remained maximum (45%) in the composite with the highest amount of lapinus fibre content and lowest amount of flyash whereas the frictional fluctuations in terms of μ_max − μ_min has been observed to be higher in case of low flyash–high lapinus fibre combination. The recovery response seemed unaffected by the disparity of ingredients and remained consistently stable within the range of 112 ± 2%. The analysis of friction and wear performance has revealed that flyash along with lapinus fibre provide thermo-mechanical stability and overall mechanical integrity to the system causing reduction in friction-fade whereas wear was found to be more recovery-controlled and less fade controlled. Worn surface morphology investigation using SEM has been carried out which has revealed that the interplay of flyash–lapinus combination and topographical attributes vis-a-vis dynamics of contact patches (formation–destruction) largely influence the friction and wear performance of such composites.     

Design synthesis and structural optimization of a lightweight,monobloc cast iron brake disc with fingered hub

This article focuses on generating a monobloc fingered hub (top-hat) disc design, aiming at reducing disc mass but maintaining rotor thermal capacity, while also improving heat dissipation characteristics. The analyses and tests demonstrated that such a design is possible to achieve, with mass reduction of just over 9%. The activities included research into cast iron modelling, which gave very important insights into the limits of mechanical performance under bending. Initial finite element analyses enabled considerable progress to be made towards establishing a baseline design, but only through shape optimization and topology optimization procedures was the full potential of the design accomplished. Shape optimization facilitated the reduction of maximum principal stress by 32%, considerably improving disc torsional strength with practically no increase in mass. The safety factor in torsion achieved a value of 3.57. Topology optimization provided further, although small, mass reduction (1.5%) while maintaining low stress levels.     

Back to the future: Brake reaction times for manual and automated vehicles

Rear-end collisions are often quoted as being a major cause of road traffic accidents. In response to this, a great deal of ergonomics research effort has been directed towards the analysis of brake reaction times. However, the engineering solution has been to develop advanced systems for longitudinal control, which, it is argued, will mitigate the problem of rear-end collisions. So far, though, there have been few empirical studies to determine how brake reaction times will be affected by such vehicle automation. This paper presents a literature review summarizing the current state of knowledge about driver responses in non-automated vehicles. The review covers driver factors, vehicle factors and situational factors. Following the review, some empirical data are presented from a driving simulator experiment assessing brake reaction times of skilled and unskilled drivers under two different levels of automation. When compared to previous data gathered during manual driving, there seems to be a striking increase in reaction times for these automated conditions. Implications for the design and safety of automated vehicle systems are discussed.     

用有限元法计算盘式制动器非稳态温度场

本文计算了盘式制动器在制动期间的摩擦温度场,这种方法是可行的,计算结果与实测值对比表明,可在摩擦制动器设计时预算温升过程,从而可为制动器的设计提供有利条件。     

开关磁阻电机并网逆变模块设计

应用PWM整流器技术设计了一种开关磁阻电机并网逆变模块,在不改变功率变换器主电路的情况下,将开关磁阻电机在发电状态下发出的能量回馈电网。     

圆锯安全自控装置制动性能的微机测试系统

本文针对圆锯安全自控装置的制动性能，设计了一种实用的微机测试系统，同时介绍了该系统的关键技术，并对实测结果进行了综合分析。     

无线通信的踏板力测试仪的设计

为了增加汽车检验的透明度,提出了一种新型的带有无线通信功能的踏板力测试仪的设计思路,实时地将测试数据传输到总控制室大屏幕并显示。介绍了将混合信号系统级的单片机做为核心器件,并配以无线通信模块的系统硬件框架、软件设计以及与之相关的算法设计。实践证明这样的设计更加人性化更具科学性。