为了了解中国城市交通中车辆碰撞行人事故的形态,在中国长沙地区开展了深入的调查。共采集2001年至2006年期间行人事故案例497例,其中446例具有详细的事故信息,信息来源包括警察、医院和回勘调查。通过现场调查采集到51例行人事故。所...为了了解中国城市交通中车辆碰撞行人事故的形态,在中国长沙地区开展了深入的调查。共采集2001年至2006年期间行人事故案例497例,其中446例具有详细的事故信息,信息来源包括警察、医院和回勘调查。通过现场调查采集到51例行人事故。所有采集的事故数据被存档于长沙市深入的车辆交通事故调查数据库(IVAC)中。基于497例数据进行了统计分析,分析结果与瑞典STRADA(Swedish TRaffic Accident Data Acquisition)数据进行了对比研究。结果表明:长沙地区的行人死亡率高出瑞典2倍多,两个地区的大多数行人事故均发生在良好的照明条件和干燥气候条件下;与瑞典相比较,长沙的行人事故形态分布呈现出显著的不同。展开更多
The electroplastic effect in AZ31B magnesium alloy sheet was investigated through uniaxial tensile tests. In order to show the athermal effect of the electrical pulses, two types of uniaxial tensile tests at the same ...The electroplastic effect in AZ31B magnesium alloy sheet was investigated through uniaxial tensile tests. In order to show the athermal effect of the electrical pulses, two types of uniaxial tensile tests at the same testing temperature were carried out: uniaxial tension in environmental cabinet and uniaxial tension with electrical pulses. In addition, the distribution of temperature field in the cross-section area during uniaxial tension with electrical pulses was simulated. The results show that the distribution of temperature field along the cross-section area is homogeneous. By comparing the true stress?true strain curves of AZ31B alloy under uniaxial tensile tests, the athermal effect with electrical pulses was confirmed. The microstructure evolution after the uniaxial tension was studied by optical microscopy. The results indicate that the electrical pulses induced dynamic recrystallization plays an important role in the decrease of flow stress. Finally, a flow stress model of AZ31B sheet taking the influence of electroplastic effect into account was proposed and validated. The results demonstrate that the calculated data fit the experimental data well.展开更多
文摘为了了解中国城市交通中车辆碰撞行人事故的形态,在中国长沙地区开展了深入的调查。共采集2001年至2006年期间行人事故案例497例,其中446例具有详细的事故信息,信息来源包括警察、医院和回勘调查。通过现场调查采集到51例行人事故。所有采集的事故数据被存档于长沙市深入的车辆交通事故调查数据库(IVAC)中。基于497例数据进行了统计分析,分析结果与瑞典STRADA(Swedish TRaffic Accident Data Acquisition)数据进行了对比研究。结果表明:长沙地区的行人死亡率高出瑞典2倍多,两个地区的大多数行人事故均发生在良好的照明条件和干燥气候条件下;与瑞典相比较,长沙的行人事故形态分布呈现出显著的不同。
基金Projects(50975174,51275297)supported by the National Natural Science Foundation of ChinaProject(20100073110044)supported by the Education Ministry of China
文摘The electroplastic effect in AZ31B magnesium alloy sheet was investigated through uniaxial tensile tests. In order to show the athermal effect of the electrical pulses, two types of uniaxial tensile tests at the same testing temperature were carried out: uniaxial tension in environmental cabinet and uniaxial tension with electrical pulses. In addition, the distribution of temperature field in the cross-section area during uniaxial tension with electrical pulses was simulated. The results show that the distribution of temperature field along the cross-section area is homogeneous. By comparing the true stress?true strain curves of AZ31B alloy under uniaxial tensile tests, the athermal effect with electrical pulses was confirmed. The microstructure evolution after the uniaxial tension was studied by optical microscopy. The results indicate that the electrical pulses induced dynamic recrystallization plays an important role in the decrease of flow stress. Finally, a flow stress model of AZ31B sheet taking the influence of electroplastic effect into account was proposed and validated. The results demonstrate that the calculated data fit the experimental data well.