桥梁维修加固中粘贴钢板的造价分析

粘贴钢板是目前广西桥梁维修加同中的常用方法,此方法能充分利用旧桥,降低工程造价,并能尽快恢复通行。文章通过对粘贴钢板的工、料、机、价格构成分析,探讨如何编制补充定额计算粘贴钢板的造价。     

汽车转向轮前束与车轮外倾角的设计匹配

重点对转向轮前束与转向轮外倾角的设计匹配进行分析计算,并对东风汽车公司生产的EQ1141G车型和美国通用汽车公司的某高机动性能越野车进行了检验验算,得出了合理的结论,解决了长期困扰汽车转向设计师的转向轮前束与转向轮外倾角的设计匹配难题。     

喷撒颗粒的增粘机理研究

本文建立了向轮轨接触间喷撒颗粒时的摩擦模型，并将此摩擦模型应用于修正的轮轨粘着理论中，对喷撒颗粒的增粘机理进行了理论研究。从理论计算结果可以看出，向轮轨接触间喷撒颗粒的增粘效果是非常明显的，且增粘效果和轮轨的表面状态、颗粒的质量和进入轮轨接触面间的颗粒数量有关。     

起动机渐开线螺旋花键轴的设计及其冷滚轧技术

汽车用起动机电枢轴上的螺旋花键，已多采用冷滚轧加工的多键渐开线螺旋花键来代替铣削加工的四键或六键的矩形花键。阐述了渐开线螺旋键冷忆使用的新轧轮的特点及应用；指明了渐开线螺旋花键轴几何尺寸设计时应注意的问题。     

水下盾构隧道管片钻穿引起的涌水突泥治理技术研究

水下盾构隧道管片钻穿会引起大量涌水突泥，对隧道建设及运营造成重大影响，且采取的隧道修复措施将影响隧道的长期运营安全。以某地铁隧道被意外钻穿的实例为工程背景，为确保水下隧道意外钻穿破坏时，可以做到临时封堵有效，永久修复满足百年使用要求，提出修复思路。在水面利用浮船进行海上袋装水泥封堵，然后筑岛截断隧道与海水的联系； 临时封堵后监测管片变形、复核隧道中线，明确钻孔对隧道限界的影响； 通过计算对结构安全性进行评价，明确钻孔对管片结构受力影响较小。在确保隧道钻穿对隧道限界及结构的影响可控后，采取地面注浆、洞内注浆、倒锥形封堵、洞内设置内撑钢板相结合的方案，对隧道钻穿处进行治理，保证隧道的安全运营。在隧道周边施工时，应加强隧道保护意识，避免对既有隧道造成破坏。     

天然气爆炸对盾构隧道的作用机制及工后修复

为了使爆炸灾害后的盾构管片得到合理的修复方案,以某地铁盾构施工过程中挖破天然气管道导致爆炸事故为背景,通过介绍爆炸的基本特性、冲击波的传播特点及火焰波的伴生关系,归纳在天然气爆炸过程中,爆炸火焰和冲击波是决定事故危害程度的2个主要因素,同时这些因素中最危险、破坏力最强、破坏区域最大的是冲击波的破坏效应。通过计算隧道内满布天然气时的TNT当量,以及采用拟静力法模拟管片内部的超压分布并计算得到管片的变形,与第三方检测数据中的管片变形指标进行耦合,证明模拟的准确性,为提出合理的区间修复方案提供依据,同时也为类似工程事故的处理和预案提供经验。     

化学注浆工艺加固高速公路路基应用实例

化学注浆工艺就是将快凝早强的水泥浆通过一定压力注入路基,挤出路基内含水,并将松散的路基材料重新凝结成整体,达到提高承载力的目的。该文根据实施实例,介绍了化学注浆工艺加固公路路基的主要步骤及取得效果,对既有道路的维修养护施工具有一定参考价值。     

An ABS control logic based on wheel force measurement

The paper presents an anti-lock braking system (ABS) control logic based on the measurement of the longitudinal forces at the hub bearings. The availability of force information allows to design a logic that does not rely on the estimation of the tyre–road friction coefficient, since it continuously tries to exploit the maximum longitudinal tyre force.

The logic is designed by means of computer simulation and then tested on a specific hardware in the loop test bench: the experimental results confirm that measured wheel force can lead to a significant improvement of the ABS performances in terms of stopping distance also in the presence of road with variable friction coefficient.     

The impact of structural flexibilities of wheelsets and rails on the hunting behaviour of a railway vehicle

The hunting motion of a passenger coach is investigated using a multibody system in which the wheelsets and the rails can be modelled as flexible bodies. By comparing the results for different model variants, in which the structural flexibilities of the wheelsets and of the rails are either taken into account or neglected, the impact of the flexibilities is analysed. It turns out that the flexibilities of both the wheelsets and the rails have a significant impact on the hunting behaviour by increasing the lateral motions of the wheelsets and lowering the critical speed. In order to investigate the impact of the flexibilities under different operating conditions, the calculations are carried out for track geometries using different rail profiles (60E1, 60E2) and different rail cants (1:40, 1:20) and for different values for the friction coefficient (0.25…0.4) at the wheel–rail contact. The results show that the influence of the flexibilities is the strongest for high lateral forces, which occur e.g. for contact geometries leading to high hunting frequencies and for high values of the friction coefficient. The results also show in some cases a strong impact of the flexibilities on the position of the wheel–rail contact on the running surface of the rail, which is of particular interest with respect to wear simulation.     

低动力作用货车转向架动力性能的研究

本文探讨低动力作用货车转向架的原理及其动力性能的计算和评估方法。首先定义9项指标,作为衡量车辆对轨道动力作用的标准。然后研究这些指标的诸因素。在此基础上总结出实现低动力作用的基本途径。本文还应用这些研究成果,提出4种低动力作用货车转向架的设计方案,并通过数值计算,同国内、外主型货车转向架对比,从而论证其在我国铁路采用的可行性。