Freakish sea index and sea states during ship accidents

Sea states during seven marine accidents near Japan reported in the media were analyzed using a third-generation wave model. Based on the estimated evolution of the directional wave spectrum, a narrowing of the directional spectrum was suggested for five cases. Based on earlier studies in laboratory tanks, the narrowing of the directional spectrum may be associated with increased probability of freak waves at the time of the accident. A diagram mapping the frequency bandwidth and directional spread proved useful as a diagnostic tool. This freakish sea index was compared against recently conducted ocean wave observations. The accident causes are discussed in the context of slamming, green sea loading, loss of stability, broaching and other possibilities.     

新干线高速试验列车车辆间平滑罩的改进

介绍了FAsTECH360S新干线高速试验列车上安装的最初的车辆间平滑罩存在的问题,并针对这些问题对该平滑罩进行了改进。通过长期运行试验和其他试验,对其耐久性、可维护性等进行了评价。     

Dynamics of Automated Guideway Transit Vehicle with Single-axle Bogies

Summary The steering type of a mechanical guidance system has been used for Automated Guideway Transit (AGT) system in Japan. Recently, the single-axle bogie system has developed for AGT vehicle and applied to Yurikamome 7200 type vehicle. This paper describes dynamic characteristics of AGT vehicle with single-axle bogies. Introducing a nonlinear, 15 degree-of-freedom dynamic model, a computer simulation study on the lateral motion of the AGT vehicle with single-axle bogies are carried out. In order to show the dynamic characteristics of the single-axle bogie clearly, it is compared to that of the AGT vehicle with conventional steering system. The simulation study with actual vehicle parameters shows that single-axle bogie has suitable characteristics for AGT system. The multi-body dynamics modeler, DADS, is used to build the dynamic model of AGT vehicle with single-axle bogies and this is used to demonstrate the vehicle motion in actual guideway. Obtained results are compared to that of the field test. It is shown that the vehicle dynamic response can be obtained in realistic situation by using multibody dynamics code, that is useful for designing both vehicle and guideway.     

与磁悬浮车辆现有超导磁体合为一体的线性发电机

在使用超导磁体(SCM)的磁悬浮运输系统中,研究了将线性发电机(LG)并入现有SCM,以提高输出功率、改善功率因数和测量系统的可行性,并在山梨磁悬浮试验线进行了试验。分析和运行试验测量的结果有良好的相关性,有望将线性发电机投入实际应用。     

Control and monitoring for railway vehicle dynamics

Over the last twenty to thirty years, railway vehicle dynamics has changed from being an essentially mechanical engineering discipline to one that is increasingly starting to include sensors, electronics and computer processing. This paper surveys the application of these technologies to suspensions and running gear, focused upon the complementary issues of control (which has been reviewed within Vehicle System Dynamics previously) and monitoring (which has not previously been reviewed). The theory, concepts and implementation status are assessed in each case, from which the paper identifies the key trends and concludes with a forward look at what is likely to develop over the next years.     

止裂韧度值Kca的实尺模型试验研究

对船用钢进行长裂纹止裂特性研究表明:它们的脆性裂纹止裂能力不够。TMCP钢有足够的脆性裂纹止裂能力。对船用钢进行了两种实尺(actual-scale)模型试验,明确了脆性裂纹扩展的条件。根据试验结果提出了止裂韧度值Kca,已经归纳在"脆性裂纹止裂设计指导性文件"中。     

Dynamic Identification of Driver-Vehicle System Using AR-method

When investigating dynamics of a driver-vehicle system, isolation between driver dynamics and vehicle dynamics becomes important, because interaction between them exists in the closed-loop system. The subject of this study is to examine effectiveness of AR-method by which each dynamics can be identified. The AR-method applied to lane changes, usually having rather short duration data, provides usefullness for the isolation. This method well reflects variation of subject drivers in identified results, and time series data recoverd by identified VAR-model is consistent with field data.     

Static and Dynamic Performance of Permanent Magnet Suspension for Maglev Transport Vehicle

The design and performance of a mechanical air gap controller for a maglev transport vehicle are described. The basic requirement for a functional design of the controller is derived first and its effectiveness is shown by experiments. After the construction of dynamic vehicle models dynamic characteristics of the maglev vehicle are introduced and the stability criteria for magnetic levitation are derived. The effect of a dead zone in the mechanical air gap controller and nonlinear characteristics of the magnets, which are expected to exert a large influence on vehicle levitation performance, are investigated by simulations. The simulation results show that a low control lever ratio causes sudden deterioration of the levitation performance if there exists a dead zone in the controller, and a suitable control lever ratio which is unaffected by the dead zone is proposed. Finally, field test results with an actual maglev transport vehicle are shown and the dynamic levitation performance of the vehicle is discussed.