Numerical simulation of the water entry of a structure in free fall motion

To solve the problems concerning water entry of a structure, the RANS equations and volume of fluid （VOF） method are used. Combining the user-defined function （UDF） procedure with dynamic grids, the water impact on a structure in free fall is simulated, and the velocity, displacement and the pressure distribution on the structure are investigated. The results of the numerical simulation were compared with the experimental data, and solidly consistent results have been achieved, which validates the numerical model. Therefore, this method can be used to study the water impact problems of a structure.     

Scheduling highway work zones with genetic algorithm considering the impact of traffic diversion

Highway work zones caused excessive delay to road users. To reduce user and maintenance costs, work zones shall be designed and scheduled accordingly. An analytical model is developed to jointly optimize work zone lengths and schedule as well as diverted traffic volume for highway maintenance projects, considering time‐varying demand, variable maintenance cost, and various production rates of maintenance crew. With a genetic algorithm, an iterative procedure is developed to search for the optimal solution. A numerical example is illustrated, in which various traffic mitigation plans for a highway maintenance project are evaluated. A sensitivity analysis is conducted, and results indicate the threshold volumes for various conditions (e.g., maintenance crews and capacity of the work zone) at which diverting traffic is desirable. This study demonstrates an effective approach to search for the optimal work zone schedule, which is also applicable to evaluate the effectiveness of traffic diversion plans for a pre‐planned work zone schedule. Copyright © 2012 John Wiley & Sons, Ltd.     

Aesthetic visual style assessment on Dunhuang murals

Dunhuang murals are gems of Chinese traditional art. This paper demonstrates a simple, yet powerful method to automatically identify the aesthetic visual style that lies in Dunhuang murals. Based on the art knowledge on Dunhuang murals, the method explicitly predicts some of possible image attributes that a human might use to understand the aesthetic visual style of a mural. These cues fall into three broad types: ① composition attributes related to mural layout or configuration; ② color attributes related to color types depicted; ③ brightness attributes related to bright conditions. We show that a classifier trained on these attributes can provide an efficient way to predict the aesthetic visual style of Dunhuang murals.     

主动前轮转向的操纵稳定性研究

汽车的主动前轮转向作为汽车主动控制的一个重要组成部分,可以改善车辆的操纵稳定性;横摆角速度与质心侧偏角作为表征车辆操纵稳定性的2个主要指标,可以作为车辆处于稳定状态的参考。基于模型预测控制方法,在汽车线性二自由度模型的基础上,使用相同工况下理想的横摆角速度与质心侧偏角作为参考,设计了模型预测控制器,将二自由度汽车模型与CarSim整车模型进行了联合仿真。结果表明:模型预测控制方法相对PID控制方法更能有效地提高汽车的主动安全性。     

乘用车内饰四连杆机构设计探讨

为节约乘用车内部空间,提出了一种四连杆机构设计方法,以计算四连杆的杆长及改进桌板类机构,实现了所要求的闭合与开启位置。     

城市隧道纵向通风延迟效应的机理研究及影响因素分析

纵向隧道通风动态过程现场试验结果表明,当改变隧道射流风机的运行状态后,隧道风速需要较长的时间才能达到稳定状态,即纵向通风隧道存在延迟效应。通过理论公式推导得出的隧道流场在风机调控下的动态响应公式,可用来预测隧道延迟效应的强弱,其理论计算结果与现场实测数据吻合良好。参数化研究发现:在相同初始速度下,开启射流风机数量越多,隧道风速达到稳定的时间越短;关停射流风机数量越多,隧道风速达到稳定的时间越长。在启停相同数量射流风机的条件下,初始速度越小,隧道风速达到稳定的时间越长;隧道越长、截面积越大、隧道壁面越光滑,稳定时间越长,通风延迟效应越显著。     

混合动力商用车AMT挡位自学习控制技术优化

在混合动力商用车电控机械式自动变速器(AMT)系统中,因制造、装配、磨损、更换等导致变速器各挡位置存在差异及变化,引起选换挡成功率降低甚至工作异常,需通过AMT挡位自学习解决此问题。针对AMT静态时各挡位位置自学习控制策略提出了优化,主要包括挡位学习顺序和再次进挡学习策略,通过自整定PID技术进行自适应参数优化。经过试验验证,提高了自学习成功率、合格率、效率和一致性。     

车身轻量化方法研究

分析车身轻量化流程,界定各部门的角色任务;研究车身轻量化目标值的确定方法,简述车身轻量化的三种主要措施.     

纯电动汽车两档自动变速器换档品质研究

纯电动汽车变速器需要符合驱动电机特性并利用同步器使将要啮合的齿轮达到一致的转速而顺利啮合,从而实现电动汽车换档变速的功能。所研究的纯电动汽车变速器无离合器,仅依靠电机的调速性能和同步器共同作用换档。通过对同步器的滑磨功和换档冲击度进行分析,利用电机自身的调速特性,减小主、被动齿轮转速差,减轻同步器磨损,缩短换档时间,从而提高变速器的换档品质。     

CAN总线在汽车线控制动系统上的应用

线控制动系统(BBW)作为制动的发展方向逐渐取代以液压或气压为特点的传统制动系统,将CAN总线加入到线控制动中无疑是电子制动的一次提升。介绍了汽车线控制动系统的分类和工作原理,总线的选型和CAN在汽车上的应用;详细阐述了CAN总线在线控制动系统上的应用,包括系统方案、节点接口电路设计;CAN总线应用于线控制动系统能简化结构,提高可靠性,方便诊断维修,具有良好实用价值。