汽车后门外板件冲压成形CAE研究

介绍了金属板料冲压成形数值模拟理论和主要步骤。利用Dynaform软件完成了汽车后门外板件冲压成形过程的仿真,得到了优化的工艺参数。模拟结果验证了方法的可行性。

公交车后市场零部件供应商的评价与选择

为了进一步优选公交车零配件,提升公交企业的维修运营效率,建立零配件供应商的选择与评价体系尤其重要。本文介绍了公交车后市场供应商相关理论,分析了公交车后市场及零部件供应商选择与评价现状,对汽配市场存在的问题进行分析,探讨构建了公交车后市场零部件供应商评价指标体系的方法,并验证了公交企业利用熵权-TOPSIS评估法进行零配件选择与评估的过程。

小心车后

“嘭”的一声巨响．一个卖豆腐的小推车在青云路撞到了一辆大货车上。大货车后面盼车灯被撞坏了，小豆腐车更惨，撞散了架子，一车刚刚出锅的豆腐——冒着热气香香的豆腐全摔在地上，变成了碎屑。看来出门不光要看前面，还要留意后面。

热塑性聚氨酯弹性体在汽车上的应用

简述了热塑性聚氨酯弹性体(PUR-T)的结构和性能特点,详细介绍了PUR-T在汽车上的应用情况,以及在汽车保险杠、车内电缆包覆层、车内薄层蒙皮、车后窗、汽车保护膜、汽车防滑链等部件上的应用实例,并对其未来的应用发展作了展望。

流媒体全视屏后视镜的设计

安全驾驶是人们出行的第一要务,传统内后视镜采用光学反射的原理为驾驶员提供车后方视野,但由于车体结构的特点,C柱结构、造型和后排靠枕(物品等)都会带来一定的视野盲区,以及雨雾天气,对视野产生影响。本文提出一种流媒体全视屏后视镜方案可解决车后盲区监测问题,满足人们日常驾驶观测车后方路况实时性和清晰度的需求,同时还具备防眩目内后视镜功用,能够有效地提升安全驾驶系数。

Modelling of vehicle interaction behavior during discretionary lane-changing preparation process on freeway

In order to increase the accuracy of microscopic traffic flow simulation,two acceleration models are presented to simulate car-following behaviors of the lane-changing vehicle and following putative vehicle during the discretionary lanechanging preparation( DLCP) process, respectively. The proposed acceleration models can reflect vehicle interaction characteristics. Samples used for describing the starting point and the ending point of DLCP are extracted from a real NGSIM vehicle trajectory data set. The acceleration model for a lanechanging vehicle is supposed to be a linear acceleration model.The acceleration model for the following putative vehicle is constructed by referring to the optimal velocity model,in which optimal velocity is defined as a linear function of the velocity of putative leading vehicle. Similar calibration,a hypothesis test and parameter sensitivity analysis were conducted on the acceleration model of the lane-changing vehicle and following putative vehicle,respectively. The validation results of the two proposed models suggest that the training and testing errors are acceptable compared with similar works on calibrations for car following models. The parameter sensitivity analysis shows that the subtle observed error does not lead to severe variations of car-following behaviors of the lane-changing vehicle and following putative vehicle.

Changes in blood alcohol concentration and driving ability after alcohol intake

Objective: To study the relationship between the amount of consumed alcohol, blood alcohol concentration (BAC), and driving ability among a part of the population in Southwest China and to provide reference for the formulation of the legal limits for safe driving. Methods: Seventy-six randomly selected volunteer drivers each had three times of alcohol intake (100 ml each time). After each drank, BAC was measured with gas chromatograph and driving ability was evaluated. The drivers were grouped according to age, weight, alcohol tolerance and driving experience respectively and changes in BAC and driving ability were analyzed. Results: Average BAC and the percentage of drivers showing impaired driving ability in the groups increased after each intake of 100 ml alcohol. BAC in Group≤60 kg was more susceptible to alcohol than that in Group>60 kg. When each drank, alcohol had greater influence on drivers who had comparatively shorter driving experience. Conclusion: Volume of consumed alcohol, BAC and driving ability have direct associations among one another and are all under the influence of various factors including individual conditions. To set an appropriate legal BAC limit for safe driving should take an overall consideration of all factors.

The Information Modeling and Intelligent Optimization Method for Logistics Vehicle Routing and Scheduling with Multi-objective and Multi-constraint

The vehicle routing and scheduling (VRS) problem with multi-objective and multi-constraint is analyzed, considering the complexity of the modern logistics in city economy and daily life based on the system engineering. The objective and constraint includes loading, the dispatch and arrival time, transportation conditions,total cost,etc. An information model and a mathematical model are built,and a method based on knowledge and biologic immunity is put forward for optimizing and evaluating the programs dimensions in vehicle routing and scheduling with multi-objective and multi-constraints. The proposed model and method are illustrated in a case study concerning a transport network, and the result shows that more optimization solutions can be easily obtained and the method is efficient and feasible. Comparing with the standard GA and the standard GA without time constraint,the computational time of the algorithm is less in this paper. And the probability of gaining optimal solution is bigger and the result is better under the condition of multi-constraint.

A new braking force distribution strategy for electric vehicle based on regenerative braking strength continuity

Regenerative braking was the process of converting the kinetic energy and potential energy, which were stored in the vehicle body when vehicle braked or went downhill, into electrical energy and storing it into battery. The problem on how to distribute braking forces of front wheel and rear wheel for electric vehicles with four-wheel drive was more complex than that for electric vehicles with front-wheel drive or rear-wheel drive. In this work, the frictional braking forces distribution curve of front wheel and rear wheel is determined by optimizing the braking force distribution curve of hydraulic proportional-adjustable valve, and then the safety brake range is obtained correspondingly. A new braking force distribution strategy based on regenerative braking strength continuity is proposed to solve the braking force distribution problem for electric vehicles with four-wheel drive. Highway fuel economy test(HWFET) driving condition is used to provide the speed signals, the braking force equations of front wheel and rear wheel are expressed with linear equations. The feasibility, effectiveness, and practicality of the new braking force distribution strategy based on regenerative braking strength continuity are verified by regenerative braking strength simulation curve and braking force distribution simulation curves of front wheel and rear wheel. The proposed strategy is simple in structure, easy to be implemented and worthy being spread.

Research on the Drunk Driving Intelligent Test System Based onμC/OS- II

The article design the hardware system scheme using STM32F407 as the control core circuit, and designed the software structure of the system and application layer multi task and priority based on transplanted μ C/OS operating system. Aimed at that the traditional drunk driving detection system has low sensitivity and unable to distinguish diffuse alcohol sigmal interference. For accurate identification of pilot and crew alcohol concentration, the paper puts forward a driving intelligent identification wine system based on embedded μC/OS- II. The experimental results show that the detection sensitivity of the system has high accuracy rate, effectively prevent the purpose for the prevention of drunk driving, drunk driving has very good practical value.

公交车上机智擒贼

车终于来了.在车站等候已久的我早已不耐烦了,一个箭步就跨进了车厢。我的运气还真'不错',等车等了半个小时,上了车后没有座位,连能不能在一个地方站住脚都是个问题呢。人群间推推搡搡。突然,我发现一个贼眉鼠眼的人,他的眼睛到处瞄着——一看就不像是好人。

Correlation between high-resolution climate records from a Nanjing stalagmite and GRIP ice core during the last glaciation

A 400-mm-long stalagmite from Tangshan Cave, Nanjing has beenanalyzed by a high-precision TIMS-U series dating method and also determined for oxygen and carbon stable isotopic compositions. The results provided a high-resolution paleoclimate record for eastern China during a time interval (from 54 000 to 19 000 aBP) of the last glaciation. The continuous record of oxygen-18 variations in the stalagmite, indicating a precipitation history of the East Asian monsoon, shows not only signals of the Heinrich events, but also the Dansgaard-Oeschger cycles which are first found in the last glacial climate record of the East Asian monsoon area. Although the stalagmite-based climatic signals match well with the GRIP ice core record, some differences between the two re-cords can be recognized: (1) The last glacial climate changes in eastern China exhibited a long-term remarkably cooling trend, superimposed on which were four successive Bond’s cycles illus-trated by the δ18O curve. This strong cooling tendency may be an effect of the strong summer mon-soon event during the MIS 3 over the Tibetan Plateau. (2) There exist some phase differences of 1000—2000 years between the cooling events in the stalagmite-based climate signal and the GRIP ice core record. Such differences should be further verified by calibrations of multiple dating meth-ods.

Experiment and analysis on microscopic characteristics of pedestrian movement in building bottleneck

In this paper, evacuation experiments are carried out to study pedestrian movement behaviors in building bottleneck. An image processing method based on mean-shift algorithm is used to extract pedestrian movement trajectory. Based on the extracted trajectory, we analyze the microscopic movement characteristics of pedestrians such as lane formation, change of velocity and distance between two sequential pedestrians. A pedestrian lane is a group of pedestrians moving in a column. The lane formation is verified by the pedestrian trajectory and distribution of pedestrian’s lateral positions (x direction in the paper): lane number changes from one to two, three or even more with the increasing bottleneck width when pedestrians pass through the bottleneck. By analyzing the pedestrian movement behaviors in the same pedestrian lane, we find three typical movement modes in the bottleneck: time-lag acceleration, synchronous acceleration, and avoiding deceleration. Through analyzing the time intervals when successive pedestrians pass through the bottleneck, we find that most pedestrians adjust their velocities according to the distance to the forward pedestrians. Results also indicate that due to different cultures, pedestrians flux in China and Germany may have some differences besides their similarities.