Rollover detection and control on the non-driven axles of trucks based on pulsed braking excitation

The major challenges for rollover detection are the accurate modelling of vehicle dynamics and the real-time estimation of the varied parameters. To circumvent the dependence on vehicle parameters, a novel rollover detection method based on the pulsed braking excitation is proposed. With the lateral load transfer ratio (LTR), the relationship between rollover risks and non-driven wheel rotational dynamics is deduced, which is the basis to apply braking excitation on wheels. The lateral acceleration is adopted as the first criterion to activate the rollover detection. Once the pulsed braking is applied to the non-driven wheels, the braking pressure and wheel angular speeds are measured to estimate the LTR on the non-driven axle. In case of emergency, the differential braking-based anti-rollover is implemented. Experiments were conducted on a Hardware-in-Loop bench. The results show that, the pulsed braking can be activated timely, and the LTR on the non-driven axle is estimated accurately. With the anti-rollover control, the roll stability is improved considerably.     

Lead–lag relationship between new-building and second-hand ship prices

We examine lead–lag relationships between new-building and second-hand ship prices. Our analysis shows the existence of a one-directional lead–lag relationship between two ship prices. The direction of lead–lag relationship is not affected by the time evolution and age of second-hand ships, but is affected by the division of shipping sector. Particularly, directions of ship price movements in dry bulk and tanker shipping sectors are opposite. We argue that the opposite directional lead–lag relationships are caused by the difference in competition levels and the difference in the purposes of trading in the two shipping sectors.     

HX_D2型机车转向架加工工装分析

通过技术引进,学习了国外的先进工艺,总结了5个较好的加工工艺思路,有广泛应用范围和一定的推广价值。     

交通拥挤的经济学分析

本文以交通拥挤问题为研究对象,用微观经济学的方法分析其产生的原因、现有的解决方案,并以上海为例分析了适合我国国情的最优策略之一--"公交优先"系统的经济学意义.     

天然气水合物运输船

介绍了天然气水合物的概念,阐述了天然气水合物的优势及天然气水合物运输船发展现状。     

勘察设计企业保密工作浅析

结合从事档案管理及保密工作的实际，对勘察设计企业保密工作的重要性及如何做好这项工作进行探讨。     

京津城际铁路岔区板式无砟轨道结构设计

京津城际轨道交通在我国首次将板式无砟轨道成功应用于道岔区.介绍了岔区板式无砟轨道的结构组成、型式尺寸、技术特点及技术要求;对岔区板式无砟轨道进行了力学分析及配筋设计;简要阐述了岔区板式无砟轨道综合接地系统及过渡段设计处理措施.板式无砟轨道在京津城际轨道交通的成功应用,为我国岔区无砟轨道结构设计提供了新的技术方案.     

Determination of partial safety coefficients of structural reliability based on contaminated distribution

Partial safety factors must be evaluated precisely for the given target reliability index to ensure the certain level of structural reliability due to uncertain factors. The current studies of partial safety factors do not consider human error in construction for structural reliability. A mathematically model should be improved to simulate the partial safety coefficient concerned uncertainty factors which concern the effect of human error in construction. We employ the contaminated distribution to obtain the realistic mean value and standard variance of variable of structural parameters which coexist with random error human error. The reasonable partial safety coefficient can be calculated based on the realistic value of structural parameters concerned the effects of random error and gross error.     

人工神经网络理论在煤炭海运系统优化中的应用研究

本文应用人工神经网络方法，以经济指标为衡准，在考虑了航线的船型，港口装卸效率等因素后，对我国煤炭海运系统中的主要航线运量分配方案最优化进行讨论，为国家有关决策部门制订合理发展我国煤炭海运计划提供了理论依据。     

基于神经网络的汽车结构件低载强化特性确定

提出了一种基于径向基函数神经网络的汽车结构件低载强化特性确定方法。通过足够样本的训练,构造出一个有效的神经网络模型。对于给定的强化载荷和强化次数,应用构造的神经网络模型,可以确定相应的低载强化效果。经过对某汽车前梁和传动系齿轮低载强化特性的试验验证,证实了该神经网络可以准确快捷地预测不同强化载荷和强化次数下结构的强化效果。简化了计算过程,提高了计算精度,为基于低载强化的汽车产品轻量化设计带来了方便。