FSAE赛车前悬架运动学仿真及参数优化

运用Catia软件建立某FSAE赛车前悬架三维模型,并将Catia中的坐标转换成Adams软件中的坐标,建立Adams前悬架模型。针对该FSAE赛车前悬架进行双轮跳动运动学仿真,并对悬架传递比和前轮定位参数进行参数优化。     

Normal and shear forces in the contact patch of a braked racing tyre. Part 1: results from a finite-element model

In this first part of a two-part article, a previously described and validated finite-element model of a racing-car tyre is developed further to yield detailed information on carcass deflections and contact pressure and shear stress distributions for a steady rolling, slipping, and cambered tyre. Variations in running conditions simulated include loads of 1500, 3000 and 4500 N, camber angles of 0° and ?3°, and longitudinal slips from 0% to?20%. Special attention is paid to heavy braking, in which context the aligning moment is of great interest. Results generated are in broad agreement with limited experimental results from the literature and they provide considerable insight into how the tyre deforms and how the contact stresses are distributed as functions of the running conditions. Generally, each rib of the tyre behaves differently from the others, especially when the wheel is cambered. The results form a basis for the development of a simpler physical tyre model, the purpose of which is to retain accuracy over the full operating range while demanding much less computational resource. The physical tyre model is the topic of the second part of the article.     

Limit braking of a high-performance motorcycle

A mathematical-model-based study of the limit braking of a high-performance motorcycle and rider is described. Front and rear brakes are operable independently. A dry road and high friction are presumed, such that full braking of the front wheel would lead to an overturn or ‘stoppie’ in colloquial parlance. Effective braking needs to maintain some loading on the rear wheel. A planar but otherwise detailed system model is set up and braking strategies for front and rear are devised. Parameters of the braking control schemes are derived with the help of an optimisation process, minimising the final speed in braking from high speed over a fixed time interval. Simulation results are examined critically and the strategy is developed until efficient use of the friction available is made. The nature of optimal braking events is demonstrated. The influences of slipper-clutch torque setting and the rear-tyre target load chosen are shown.     

FSEC赛车电池箱结构强度有限元分析

针对FSEC赛事规则以及动力系统的需求,文章设计一种FSEC赛车电池箱体。在CATIA中建立电池箱体有限元模型,通过使用ANSYS workbench有限元仿真软件对其进行急加速、急减速、转弯、耐久等工况分析,得到电池箱体的变形云图、应力云图和疲劳交变应力云图,明确了最大应力值以及最大变形位置,为后续结构优化设计提供方向。利用ANSYS软件进行仿真驱动研发,极大提高了设计效率,促进了大赛的发展。     

FSC赛车空气套件CFD优化设计

在满足FSC赛车设计规则要求前提下,对空气套件进行了结构优化设计,重点完成了赛车尾翼的优化设计和分析。利用CFD技术对赛车车身模型进行了外流场分析,并通过在赛车尾部加装不同间隙和攻角的尾翼,进行车身外流场模拟对比分析,研究尾翼在改善赛车气动特性方面的影响规律,研究确定了空气动力学装置在不同比赛项目时的调教策略。通过对比分析赛车车辆周围气流的压力分布和速度分布规律,研究高速赛车的负升力效果,对于提高赛车的操纵稳定性和安全性具有非常重要的意义,对于指导赛车尾翼的正确安装、确定尾翼在不同比赛项目时的调教策略有一定的指导意义。     

自行车赛场设计研究

以日照自行车赛场工程为例,通过赛车场跑道的形式、跑道的最大坡度、跑道的构造以及跑道面层动摩擦系数、看台视线和跑道曲线控制的分析和阐述,对自行车赛场设计进行探讨。针对日照自行车赛场通过多年承担全国性场地比赛的考验,验证其技术参数取值的正确性,以冀为今后类似工程设计提供技术参考。     

越野赛车前碰撞特性仿真分析

针对越野赛车车架的强度和刚度的合理匹配问题，利用ANSYS软件建立了美国某Mini-Baja越野赛车前碰撞的有限元模型，模拟该车在乡村路面上以48km／h的速度撞树的情况，得到了碰撞过程中前横梁的位移、速度随时间变化曲线及整车应力分布图．模拟结果表明：该车车架材料的强度和刚度达到了美国FMVSS203安全法规的要求；采用有限元软件ANSYS对小型越野赛车进行碰撞分析，为材料强度和刚度的选择提供了有效的手段．     

Shear forces in the contact patch of a braked-racing tyre

This article identifies tyre modelling features that are fundamental to the accurate simulation of the shear forces in the contact patch of a steady-rolling, slipping and cambered racing tyre. The features investigated include contact patch shape, contact pressure distribution, carcass flexibility, rolling radius (RR) variations and friction coefficient. Using a previously described physical tyre model of modular nature, validated for static conditions, the influence of each feature on the shear forces generated is examined under different running conditions, including normal loads of 1500, 3000 and 4500 N, camber angles of 0° and?3°, and longitudinal slip ratios from 0 to?20%. Special attention is paid to heavy braking, in which context the aligning moment is of great interest in terms of its connection with the limit-handling feel. The results of the simulations reveal that true representations of the contact patch shape, carcass flexibility and lateral RR variation are essential for an accurate prediction of the distribution and the magnitude of the shear forces generated at the tread–road interface of the cambered tyre. Independent of the camber angle, the contact pressure distribution primarily influences the shear force distribution and the slip characteristics around the peak longitudinal force. At low brake-slip ratios, the friction coefficient affects the shear forces in terms of their distribution, while, at medium to high-slip ratios, the force magnitude is significantly affected. On the one hand, these findings help in the creation of efficient yet accurate tyre models. On the other hand, the research results allow improved understanding of how individual tyre components affect the generation of shear forces in the contact patch of a rolling and slipping tyre.     

Maximum acceptable gap between urban-guided transport vehicles and platforms for persons with disabilities: the findings of an experimental study conducted to inform policy decisions

The French ministry responsible for transport has commissioned a study aimed at providing data to determine the maximum gap size between vehicle and platform for guided transport vehicles, which would become a legal requirement. Specific experimental conditions were created, with a physical mock-up simulating a tramway and a platform and providing several gap configurations (between 20 and 50?mm for the horizontal gap and between 20 and 75?mm for the vertical step), and an experimental design based on the negotiation of gaps by wheelchairs users (mainly manual or electric powered). The experiment was conducted with 46 participants with different functional abilities. Data were collected on performance and gap negotiation time. The results of this study indicate that despite the failures observed for the 50?×?50?mm gap size during the experiment, most wheelchair users who took part in the test have successfully negotiated this gap.     

FSAE赛车悬架系统的设计与分析

根据FSAE大赛规则要求,对赛车悬架系统的类型进行了选择,并对其进行了设计,确定了悬架的基本参数,在此基础上,在Catia软件中建立了悬架总成的三维模型,对其关键零件前悬架摇臂进行了有限元分析,结果表明其强度满足要求,对实车的制造提供了一定的参考。