玻璃钢(GFRP)-混凝土复合拱试验研究

在混凝土拱的不同位置、采用不同黏贴形式黏贴玻璃钢(GFRP)得到了6个GFRP-混凝土复合拱。对GFRP-混凝土复合拱进行了加载破坏试验,并对其破坏形式、荷载挠度曲线规律、刚度规律和承载力等结构性能进行了研究。试验表明:GFRP-混凝土复合拱开裂荷载更高,开裂前的刚度明显高于普通混凝土拱,开裂后其刚度及抗裂性能也明显优于普通混凝土拱;GFRP-混凝土复合拱具有更高的极限承载力和极限变形。GFRP-混凝土复合拱中,黏贴GFRP的范围较大时,GFRP-混凝土复合拱的力学性能更优;采用环形及U形黏贴GFRP的复合拱力学性能明显优于采用单面黏贴GFRP的复合拱,但全拱环形黏贴GFRP的复合拱性能并非最优。     

Partial range scaling method based washout algorithm for a vehicle driving simulator and its evaluation

Unlike an actual vehicle, a vehicle driving simulator (VDS) has limited kinematics, workspace, and bounded dynamic characteristics making it very difficult to simulate dynamic motions of an actual vehicle. To solve these problems, a washout algorithm was developed. The developed algorithm restricts the workspace of the VDS to within the kinematic limit and makes the person driving the VDS perceive movement of an actual vehicle. However, the classic washout algorithm contains several problems, such as time delay and the generation of a wrong motion signal caused by characteristics of the filters. So the driver feels “simulator sickness,” such as fatigue, nausea, headache and so on because of differences between the sense of movement of the VDS and that of a real vehicle. In this paper, a partial range scaling method based washout algorithm, including a tilt coordination system, is developed to enhance the perception of motion and reduce simulator sickness. It is verified by a simulation, a survey, and a bio signal analysis using an electrocardiogram (ECG).     

Experimental study of the characteristics of idle vibrations that result from axial forces and the spider positions of constant velocity joints

The vibrational characteristics of automotives during idling were studied experimentally by considering the axial forces of the drive shaft and the spider positions in a constant-velocity joint. The generated forces, such as PF (plunging force) and GAF (generated axial force) in the assembly of the drive-shaft module, were measured directly by an experimental apparatus. Measurements of the GAF and PF did not show the same trends as the joint angles. They depended instead on the types of CV joints. In addition, the relationship between the offset values of the shaft and the spider positions in the tulip of the constant-velocity joint were studied. As a result, the idle vibration characteristics were affected by the variation of the spider positions and the vibrational characteristics in the axial direction of the shaft, including the amplitude and the harmonic periods.     

Simple design approach for improving characteristics of interior permanent magnet synchronous motors for electric air-conditioner systems in HEV

In this paper, a simple design method for improving the performance of an interior permanent magnet synchronous motor (IPMSM), for driving the air-conditioning compressor used in hybrid electric vehicles, is presented. There are many design methods that optimize the IPMSM. Each method deals with a variety of design factors, such as slot opening, pole arc, and rotor shape. However, as the number of design variables increases, a lot of modeling and analysis time is needed in order to improve the characteristics of an IPMSM. This paper demonstrates that the optimization of a double-layer IPMSM, satisfying the given design conditions, is possible with only a flux barrier shape design. Then, response surface methodology is applied as the optimization method, and the validity of the design approach is verified by comparison with test results.     

船舶水压场畸变试验

舰船航行时在其下方附近产生水压场。这种水压场无法消除，也极难人工模拟。水压水雷就是根据航行舰船的水压场特性而引爆的。从舰船的安全防护角度考虑，可在船体底部加装某种附体，使舰船原有水压场发生改变，从而避免引爆水压水雷。对在船底加装翼板、回转体等附体所造成的舰船水压场畸变进行了试验研究和数值计算。在拖曳水池中进行了船模水压场测量，比较了加装附体前后舰船水压场的特性，据此分析了采用舰船水压场畸变方法防御水压水雷的可行性。比较了加装翼板和回转体的防水压水雷效果。分析了在实船下加装翼板防水压水雷的可能性。     

用低成本的单个DSP控制多个单相PFC模块

提出了用低成本的单个数字信号处理器(DSP)控制多个单相功率因数补偿(PFC)模块的新方案.该方案允许不同电流额定值的多个模块并联工作,并通过单个DsP控制.基于DSP的控制,易于分流,设备小巧.文章叙述了每个PFC模块电流的测量技术和多个模块工作的输出电压和输入电流闭环控制方法.在该设计例子中,开关频率设定为120kHz,2级连续导通模式的PFC并联工作,并由单个TMS320LF2407DSP控制.实验结果表明,现代开关电源可采用该方案.     

Semi-Active Suspension with Preview Using a Frequency-Shaped Performance Index

The objective of this study is to develop a control law for a semi-active suspension for the purpose of ride quality improvement. The semi-active control law is determined by reproducing the control force of an optimally controlled active suspension while suppressing its damping coefficient variation. The performance index of the optimal control for the active suspension is modified to include frequency-shaping by use of Parseval's theorem, which allows us to de-emphasize the effects of particular variables over specific frequency bands.

Through the numerical simulations, it was found that the semi-active suspension may reduce the vertical acceleration of the driver's seat and the sprung mass motions significantly. The road-holding and tire deflections were not affected much.     

国际燃料电池汽车技术研发动态和发展趋势

在很多国家,无论是政界还是企业界,都积极支持燃料电池汽车开发,相继开展了示范项目.作者从多个角度全面介绍了各国政府、企业支持的政策和措施,并具体概述分析了国际燃料电池汽车发展新动态及我国燃料电池汽车示范项目进展.     

柴油机燃用生物柴油的排放特性试验研究

在一台四冲程直喷式柴油机上进行了燃用生物柴油混合燃料的试验研究,分析了掺混不同比例生物柴油时柴油机的燃烧与排放性能.结果表明,与燃用纯柴油相比,燃用生物柴油混合燃料可改善燃烧过程,大幅降低HC、CO的排放,但同时会引起NOx排放量的增大;燃用生物柴油可大幅降低微粒排放,且随柴油中掺混生物柴油比例的增大,降低程度也逐渐增大.