汽车用材料中多环芳烃限值与检测标准分析

多环芳烃是一类持久性有机污染物的总称,这类物质由于具有较高的脂溶性、强烈的致癌性以及难以自然降解的性质而被广泛关注。汽车产品的多环芳烃主要存在于非金属材料中。在汽车成为大众消费品的同时,人们越来越注重汽车使用中的环保与健康安全的问题。本文系统地对国内外汽车材料中多环芳烃限值要求及检测方法等相关标准进行梳理分析,形成对汽车行业禁限用物质多环芳烃的管控建议。     

Study on the derailment behaviour of a railway wheelset with solid axles in a railway turnout

ABSTRACT

Dynamic wheel–rail interaction in railway turnouts is more complicated than on ordinary track. In order to evaluate the derailment behaviour of railway wheelsets in railway turnouts, this paper presents a study of dynamic wheel–rail interaction during a wheel flange climbs on the turnout rails, by applying the elasticity positioning wheelset model. A numerical model is established based on a coupled finite element method and multi-body dynamics, and applied to study the derailment behaviour of a railway wheelset in both the facing and trailing directions in a railway turnout, as well as dynamic wheel–turnout rail interaction during the wheel flange climbing on the turnout rails. The influence of the wheel–rail attack angle and the friction coefficient on the dynamic derailment behaviour is investigated through the proposed model. The results show that the derailment safety for a wheelset passing the railway turnout in facing direction is significantly lower than that for the trailing direction and the ordinary track. The possibility of derailment for the wheelset passing the railway turnout in facing and trailing directions at positive wheel–rail attack angles will increase with an increase in the attack angles, and the possibility of derailment can be reduced by decreasing the friction coefficient.     

时速160km客货共线铁路简支T梁架设工艺与经济分析

目前在时速160km客货共线铁路设计中，通桥（2005）“2101”钢筋混凝土简支T梁逐步得到应用。此文通过对铁路架桥机架设“2101”梁的经济分析，认为如果解决了“2101”梁的架设费用这个较大的问题，它将会有广阔的应用前景。     

高速铁路矮塔斜拉桥墩塔梁固结段局部应力分析与验证

局部分析是桥梁设计中常采用的重要手段,也是设计中不可或缺的重要环节,利用实体有限元模型能反应出结构细部的受力状况,对考察结构重要部位的真实应力状态、结构设计配筋有着指导性作用。为了解高速铁路矮塔斜拉桥墩塔梁固结段的真实应力状态及验证局部分析中边界条件表达的准确性,以京沈客运专线(115+95)m双线无砟轨道预应力混凝土矮塔斜拉桥为工程背景,利用Ansys有限元建立细化的空间实体有限元模型,并对局部模型的边界条件模拟的正确性进行验证,分析表明,墩塔梁固结段进人洞角点处应力集中,应适当加强配筋,其余部位应力均满足要求,通过验证局部模型的内力传递及支反力,确保实体模型应力结果的准确性,保证结构安全。最后总结出了铁路桥梁中不失一般性的局部分析方法,从而对其他结构局部分析具有借鉴意义。     

轻型组合桥面弧形缺口应力特征分析及现场试验

为深入研究钢-UHPC （Ultra-high Performance Concrete）轻型桥面组合体系对弧形缺口的应力改善程度，结合一座大跨自锚式悬索桥，针对正交异性钢桥面板（Orthotropic Steel Deck，OSD）结构铺设UHPC层前、后2种情形，选择3种不同弧形缺口形式，分别建立空间实体有限元分析模型，并采用简化加载、响应面加载2种方式进行分析，由此获得了弧形缺口应力、变形分布规律与车辆轴载位置之间的关系，揭示了弧形缺口出现峰值拉、压应力的原因。以此为基础，采用三轴加载车分别在铺设UHPC层前、后进行现场跑车试验，采集了弧形缺口多个关注点在不同横向加载位置的应力响应曲线，获得了各点的应力极值，并与有限元结果进行了对比分析。研究结果表明：铺设UHPC前、后弧形缺口关注点应力特征随荷载分布规律基本相同，面内应力为主、面外应力较小，拉应力主要由荷载偏载产生、加载区域长，而压应力主要由荷载直接作用于弧形缺口顶部产生，且加载区域短；采用传统简化加载方式难以获得弧形缺口处准确的拉应力峰值，并可能导致应力幅偏小，并由此提出了合理的加载方式；本桥五段线弧形缺口形式受力相对较好；铺设UHPC层能有效减少弧形缺口应力峰值，并在一定程度上缓解疲劳问题，是OSD结构提高疲劳性能的一种有效方案。     

机械润滑部位进水的原因分析及防范措施

分析了机械润滑部位进水的原因、提出了检查方案,即外部观察和取样检测。在这基础上提出了控制措施。     

大型预应力混凝土箱型梁试验研究与有限元分析

在试验研究与ANSYS有限元分析相结合的基础上,对日照港一大型预应力混凝土箱型梁安全性能进行评价。ANSYS计算值与试验值吻合较好,为预应力混凝土梁的分析提供了有效的方法和途径。     

茂名港沙坝泻湖海岸泥沙运动特征分析

文章根据博贺湾的地形地貌、潮流、风浪、泥沙运动等资料,分析了沿海沙坝泻湖海岸泥沙运动特征,探讨沿海沙坝泻湖地区建设深水大港的可行性。     

小波分析的应用及其MATLAB程序实现

主要介绍几种常用的小波函数及小波分析的特点，在此基础之上又介绍了一维小波、二维小波及小波包的应用，并给出一个用MATLAB程序实现一维小波在信号奇异性检测例子。     

The relations between dry port characteristics and regional port-hinterland settings: findings for a global sample of dry ports

This paper aims at defining generic characteristics of dry ports by carrying out an analysis using a large sample of dry ports from around the world. The dataset includes details on 107 inland terminals worldwide. All dry ports in the database have been selected from studies in the extant literature before being shortlisted to fit our research scope. Data collected include terminologies used, actors driving the development, terminal throughput, total area, services provided and the relation with the corresponding seaport(s). Using statistical analysis, the paper examines how dry port parameters are influenced by (1) a different terminal set up, like sea-driven and land-driven development, developed and developing system, dry port functions; (2) specifications of the seaport with which the dry port is connected, i.e. seaport traffic, connectivity, utilization, etc. and (3) the transport leg linking dry ports and seaports. The findings could be applied to the planning and development of inland nodes from the perspectives of different stakeholders.