纯电动轿车侧面碰撞安全性能提升

阐述了侧面碰撞评价性能指标,并给出了侧碰过程中典型的3种B柱变形模式。针对电动车与传统车的区别,分析了电动车与传统车在侧碰过程中车身损毁程度的不同和对假人造成伤害的不同。通过对某款电动车具体的侧碰分析和实车验证,指出了其B柱变形模式不好,容易对假人胸部造成伤害,接着剖析车身结构,提出改善方案,对B柱中上部结构进行加强,对其底部进行减弱。再次进行仿真分析验证,证实了改进方案的合理性。     

基于侧碰安全性的车门开启问题研究及其结构优化与验证

针对汽车在侧碰试验过程中出现的车门开启问题,结合门锁子系统试验、试验拆解与变形分析以及侧碰仿真,系统化的分析导致车门开启的原因,确认导致车门门锁解锁开启的主要原因是门锁区域局部变形过大,导致外开把手弹出解锁,使得车门开启。结合文中提出的能够反映门锁区域局部变形与承受冲击载荷的量化指标,提出了一种结构优化方案,仿真结果显示优化方案的相关指标可减小70%以上,能够有效改善门锁区域局部变形及其承受的冲击载荷作用,有效防止门锁在侧碰过程中解锁开启。优化方案的侧碰试验结果验证了其有效性,试验中门锁区域局部变形小,车门未开启。本文为解决侧碰过程中的车门打开问题提供一种分析方法与设计指导。     

侧碰工况下差厚板B柱过渡区网格处理

B柱是汽车侧碰的重要安全件,差厚板B柱目前在汽车中的应用越来越广,其过渡区的数目、位置和长度影响侧碰性能。基于传统的过渡区网格处理技术,更改过渡区参数极为复杂。将B柱中部画成许多水平条状网格,通过赋予水平网格不同厚度,即可实现过渡区参数的修改,大大简化了前处理流程。文章以某白车身侧围主要结构件为模型建立侧碰工况,对比发现,两种方法B柱侧碰性能相近。基于改进方法,做了一系列过渡区不同参数的侧碰试验,并对各参数侧碰性能进行了对比分析。     

门饰板侧碰安全性能分析及结构优化

介绍了门饰板子系统侧碰性能的物理试验方法和CAE计算模型,通过CAE计算结果与物理试验结果的对比,验证了该CAE计算模型是高仿真的.提出运用门饰板CAE侧碰计算模型指导门饰板结构优化的方法,通过反复进行CAE计算和结构优化,直至满足技术指标后再开产品模具并做物理试验验证,大大节省了设计开发周期和成本.以门饰板腹部区域、肩部区域、髋部区域的结构优化设计和门饰板侧碰区域的固定点结构弱化设计为例,验证了所提方法的可行性.     

轿车侧门防撞杆对车门侧碰性能影响的数值模拟研究

参照法规,结合结构非线性动态接触碰撞响应的有限元软件LS—DYNA,对某轿车前车门进行有限元碰撞模拟分析;在不改变防撞杆质量的前提下,对改变防撞杆的截面形状、放置位置以及安装方式等8种设计方案对车门防撞杆进行改进;并通过比较分析改变前后车门侧碰的特征参数,得出防撞杆最佳改进方案,为车门防撞杆的改进设计提供了理论依据。     

车身环状框架结构断面正向轻量化设计

在深入分析主断面库作用的基础上,研究了基于关键坐标及板厚的主断面属性计算方法,探讨了满足弯扭刚度及侧碰工况约束条件下车身前门环结构的优化途径。以车身刚度及侧碰性能为约束条件,主断面属性参数为设计变量,车身结构轻量化为设计目标,采用均匀拉丁超立方试验方法进行样本点的选取,以Kriging插值近似方法构造代理模型,运用冲量梯度下降算法对数学模型进行优化求解,并通过实车试验验证了该优化方案的可行性。     

基于大壁障侧碰和75°侧柱碰的车身耐撞性和乘员损伤研究

基于侧面碰撞对乘员损伤的严重性,运用试验法和仿真法对某车型的侧面碰撞性能和乘员损伤进行研究。通过对车身侧面结构变形、速度响应、乘员损伤情况进行分析,得出了大壁障侧碰和75°侧柱碰的碰撞特性,并提出了B柱、前后门、门槛梁的优化方案。结果表明:相较于MDB壁障侧碰和90°侧柱碰,大壁障侧碰和75°侧柱碰对车身耐撞性提出了更高的要求,对前后排乘员造成了更严重的损伤。通过对侧面车身结构的优化,有效地降低了车身各部位的侵入量和侵入速度,增大了乘员的生存空间,提升了车身安全性。     

侧碰能力提升——前车门中部加强板优化分析

侧碰性能已经作为C-NCAP强制安全论证的一个必要条件,文章介绍了改善汽车侧面碰撞性能的基本方法,并详细介绍了国内某款车为满足侧碰星级而进行车门中部加强板的多个方案的研究。通过CAE强度分析、工艺可行性分析以及经济性分析,探讨了车门中部加强板的最优化改型方案,并对多个备选方案进行详细的分析,最终通过实车碰撞验证了更改方案的切实可行性。在后续车型的车门中部加强板的结构优化中,建议引进高强度材料,避免增加整车质量。     

汽车侧面碰撞B柱结构优化设计

某轿车侧碰仿真试验过程中,发现B柱上端侵入量过大,针对B柱结构进行问题分析,提出结构优化方案。经仿真验证,优化后的结构满足碰撞要求和成型要求。     

基于车辆事故深度调查的侧碰事故特征分析

侧面碰撞事故的发生率和致死率仅次于正面碰撞,而致伤率居于第一位。文章运用统计分析与对比分析的方法对侧碰事故发生道路路段和侧碰事故发生原因等进行了研究,从机动车驾驶员、车辆类型、道路类型和事故发生时间等方面对机动车-机动车侧碰事故发生情况进行分析。分析结果显示由驾驶员违法引起的侧碰事故较高,占405起侧碰事故车辆总数的52.7%,其中违法行为又以未按规定让行、违反交通信号和超速行驶这三种为最;在分析道路因素对侧碰事故的影响时发现十字路口路段侧碰事故发生较多,占所统计的405起侧碰事故案例的61%;最后分析交通环境对侧碰事故的影响时发现在10:00~12:00和14:00~16:00这两个时段发生机动车侧碰事故较多。     

Design of a Stroke Dependent Damper for the Front Axle Suspension of a Truck Using Multibody System Dynamics and Numerical Optimization

Summary A stroke dependent damper is designed for the front axle suspension of a truck. The damper supplies extra damping for inward deflections rising above 4 cm. In this way the damper should reduce extreme suspension deflections without deteriorating the comfort of the truck. But the question is which stroke dependent damping curve yields the best compromise between suspension deflection working space and comfort. Therefore an optimization problem is defined to minimize the maximum inward suspension deflection subject to constraints on the chassis acceleration for three typical road undulations. The optimization problem is solved using sequential linear programming (SLP) and multibody dynamics simulation software. Several optimization runs have been carried out for a small two degree of freedom vehicle model and a large full-scale model of the truck semi-trailer combination. The results show that the stroke dependent damping can reduce large deflections at incidental road disturbances, but that the optimum stroke dependent damping curve is related to the acceleration bound. By means of vehicle model simulation and numerical optimization we have been able to quantify this trade-off between suspension deflection working space and truck comfort.     

Structural optimization of a circumferential friction disk brake with consideration of thermoelastic instability

This research suggests a new disk brake design using circumferential friction on the disk of a front-wheel-drive passenger car. The paper compares mechanical performance between the conventional and suggested disk brakes under dynamic braking conditions. Thermoelastic instability is considered in simulation of the test condition. An optimization technique using a metamodel is introduced to minimize the weight of the suggested disk brake. To achieve this goal, the response defined in the optimization formulation is expressed in a mathematically explicit form with respect to the design variables by using a kriging surrogate model, resulting in a simple optimization problem. Then, the simulated annealing algorithm is utilized to find the global optimum. The design results obtained by the kriging method are compared with those obtained from ANSYS analysis.     

利用粒子群优化算法进行桥梁维修管理计划的优化

制定桥梁维修管理计划是一项非常繁杂的工程优化难题,使用常用的优化算法很难取得满意的结果。利用耐荷性和耐久性作为桥梁的健康指数,考虑维修方案和维修费用的问题,用费用最小化和品质最大化2种方案建立了桥梁维修管理的优化模型。探讨利用粒子群优化算法(PSO)求最优桥梁维修管理计划的解的可能性,并与作者开发系统中的遗传算法(SGA)和免疫遗传算法(IA)进行了比较,运用多样度的概念说明了粒子群优化算法(PSO)在解决这类问题的先进性。结果表明,粒子群优化算法(PSO)对于桥梁维修管理计划的优化是一种普适高效的算法;而且,考虑维修的管理期间越长,应用粒子群优化算法求解问题收敛性与其他2种方法相比显得更好,得到准最优解的频率也更高。     

基于多目标优化的公交车调度问题的模型与算法

针对1条公交线路上的公交车调度方案,综合考虑公交公司和乘客的利益,利用多目标优化的方法建立了公交车调度的数学模型,给出了载客满意度函数和乘客等待时间满意度函数,采用了高性能的遗传优化算法对全天公交车运营的状况进行了数值模拟。仿真结果表明,选择采用将全天发车策略细分18个时段的模型,可得到最优的发车时刻策略。该模型可有效地改善公交车辆运营调度优化效果,提高公交车辆的运营效率,为城市公交车辆调度管理提供了合理、有效的调度方法。     

Numerical Optimization of the Linear Dynamic Behaviour of Commercial Vehicles

The demands upon the dynamic behaviour of a vehicle can be stated as an optimization problem. The optimum solution is calculated using an iterative optimization algorithm. Scaling the problem by non-linear transformations reduces the number of iterations. Lagrange multipliers provide useful information about the sensitivity of the optimum with respect to changes of the constraints. The analysis of the dynamic behaviour is performed in the frequency domain. New structural variants are calculated using system synthesis. As an example, the engine, cab and wheel suspension systems of a tractor/semi-trailer have been optimized all together.     

A book review of “Dynamik der Kraftfahrzeuge (German)”, Dynamics of Motor Vehicles by M. Mitschke,Springer-Verlag, 1972, 529 pp., 382 figs.

SUMMARY

The demands upon the dynamic behaviour of a vehicle can be stated as an optimization problem. The optimum solution is calculated using an iterative optimization algorithm. Scaling the problem by non-linear transformations reduces the number of iterations. Lagrange multipliers provide useful information about the sensitivity of the optimum with respect to changes of the constraints. The analysis of the dynamic behaviour is performed in the frequency domain. New structural variants are calculated using system synthesis. As an example, the engine, cab and wheel suspension systems of a tractor/semi-trailer have been optimized all together.     

The Horsepower Reserve Formulation of Driveability for a Vehicle Fitted With a Continuously Variable Transmission

Summary A systematic methodology is developed for choosing the optimum ratio trajectory of a continuously variable transmission in a passenger vehicle. The optimum CVT ratio schedule is formulated as a constrained optimization problem with maximum fuel economy as the objective function and driveability concerns and physical limitations included as the constraints. The key notion to achieving good driveability is the introduction and definition of a horsepower reserve function that creates a consistent and desirable vehicle response under different driving conditions. Simulation results compare the optimized schedule's performance with several other possible ratio schedules, including the minimum brake specific fuel consumption map. Results from the optimized schedule indicate only a mild tradeoff between driveability and fuel economy relative to the other ratio schedules. The ratio optimization problem formulation and solution provide a novel and unique approach for systematically addressing driveability and fuel economy considerations associated with a continuously variable transmission.     

燃料电池混合动力瞬时优化能量管理策略研究

以提高燃料经济性为目标,采用基于瞬时优化的方法开展能量分配策略研究,并引入了蓄电池等价燃料消耗理论,将蓄电池电能消耗或者电能补充,等效为燃料电池发动机的燃料消耗量,并由此建立系统瞬时燃料消耗量函数.为保证蓄电池工作在最优的范围内,引入蓄电池的充电保持策略.仿真结果表明,按照等价燃料消耗量瞬时优化理论得出的优化结果,能提高燃料经济性,同时蓄电池SOC保持在合理范围内,对今后实车的研制具有一定指导意义.     

汽车乘员约束系统快速求解与评价程序开发应用

针对汽车乘员约束系统参数匹配与优化设计仿真分析过程中需要多次手动修改计算模型源文件和处理计算结果文件等影响分析效率的问题,应用DELPHI程序设计平台和FORTRAN语句开发了针对MADYMO软件的自动循环求解程序和基于C-NCAP正面碰撞试验规程的计算结果快速评价程序模块。通过使用该两款程序进行某A级轿车乘员约束系统参数的优化设计,证明了两个程序模块的有效性和实用性。     

基于NSGA-Ⅱ的ADAS传感器配置优选方法及应用

针对ADAS传感器配置存在冗余、利用不充分的问题,设计一种基于NSGA-II的传感器配置多目标优化方法,给出传感器安装位置及配置的优化方案,并进行仿真分析验证.