魁道沥青复原剂在路面病害处置中的应用

介绍了魁道沥青复原剂CAP在高速公路路面病害处置中的推广应用情况,供有关技术人员参考借鉴。     

Young people and the private car: A love-hate relationship

Urban mobility is one of the main concerns of the public authorities in developed countries. In France, household travel surveys are conducted every ten years in major cities to gather weekday mobility data. They enable decision-makers to better understand travel patterns, their change and their determinants, in order to adapt transport infrastructures to the population′s needs. While the automobile has allowed the level of mobility to increase since 1950, an unexpected finding has emerged from recent surveys in most developed countries, namely that there has been a marked decline in car use. Analyses show that this trend is mainly because young adults (18–34 years old) are less likely to acquire a driver′s license. This paper tries to better understand the decrease in the rate of driver′s license holding among young adults in the Lyon conurbation and to quantify the impact of the main explanatory factors in a temporal perspective. It also aims to analyze the consequences of this trend on private car use as a driver for daily trips. It quantifies the influence of economic, socio-demographic and spatial factors on driver ′ s license holding and car use by considering the responses to the last three household travels surveys conducted in the Lyon conurbation area (1995, 2006 and 2015). The temporal dimension allows us to highlight a change in the relationship between young adults and the private car in the French context.     

MTMD to increase fatigue life for OWT jacket structures using Powell's method

The Powell's method was developed to determine the optimal stiffness and damping of multi-tuned mass dampers (MTMD) in offshore wind turbine (OWT) support structures under fatigue loads. Numerical examples indicated that the Powell's method results are always better than those using MTMD formulations. With the exception of the blade passing (3P) frequency, it was found in this work that a positive integer (n) multiple of the 3P frequency will also result in a large wind-induced vibration, which can be excited by the frequency of the first structural vertical rotation mode and will cause significant fatigue damage. The first translation mode TMD installed at the tower top is efficient to increase fatigue life at the tower and brace connections, but it cannot reduce fatigue damage at the column and brace connections below the platform. The second translation mode TMD can reduce fatigue damage resulting from large wave loads and thus increase the fatigue life of the braces and columns. The mode-3 TMD with a reduction in the 3(3P) vertical rotation can effectively increase the fatigue life of the braces and columns. Thus, the appropriate use of these TMDs can be effective for the fatigue problem of OWT support structures.     

基于dSPACE的叉车自动变速器控制系统性能仿真和实验研究

对叉车发动机与液力变矩器的参数进行匹配,确定动力性换挡曲线,采用区间信息值作为换挡逻辑输入量,建立基于车速和油门开度的动力性换挡规律;依据电磁阀工作特性及换挡执行元件工作逻辑,建立电磁阀模型;通过基于dSPACE的叉车自动变速器控制系统实时仿真实验,验证所建立的叉车自动变速器控制模型的正确性,为叉车自动变速器控制器的开发提供了参考。     

体外预应力在连续箱梁桥加固中的作用

重点介绍国内第一座顶推施工的竖曲线梁桥——东莞中堂大桥(旧桥)上部结构主跨的加固方案;对该桥上部结构主跨的连续箱梁主要病害进行病因分析;着重介绍该桥上部结构连续箱梁采用增设体外预应力进行加固的设计与施工方案。     

Vertical random vibration analysis of vehicle–track coupled system using Green's function method

A vertical vehicle–track coupled dynamic model, consisting of a high-speed train on a continuously supported rail, is established in the frequency-domain. The solution is obtained efficiently by use of the Green's function method, which can determine the vibration response over a wide range of frequency without any limitations due to modal truncation. Moreover, real track irregularity spectra can be used conveniently as input. The effect of the flexibility of both track and car body on the entire vehicle–track coupled dynamic response is investigated. A multi-body model of a vehicle with either rigid or flexible car body is defined running on three kinds of track: a rigid rail, a track stiffness model and a Timoshenko beam model. The results show that neglecting the track flexibility leads to an overestimation of both the contact force and the whole vehicle vibration response. The car body flexibility affects the ride quality of the vehicle and the coupling through the track and can be significant in certain frequency ranges. Finally, the effect of railpad and ballast stiffness on the vehicle–track coupled vibration is analysed, indicating that the stiffness of the railpad has an influence on the system in a higher frequency range than the ballast.     

预应力混凝土梁式桥支座病害与防治

支座作为桥梁结构的重要构件,发挥着承重、抗震、抗击水平荷载、辅助梁体正常工作等的重要作用,其质量和性能直接影响桥梁的使用寿命.普通橡胶支座良好的耐久性、安装简易性、与稳定性能,以及低廉的价格,使之成为桥梁支座的首选构件.普通板式支座在预应力混凝土梁式桥(简支、连续、刚构)用得较多,支座病害也较多.由于人们对此病害的...     

应用地质雷达技术和管道探摄仪探查管道病害

简单阐述了地质雷达探查技术的原理和管中探摄方法,结合具体工程实例,讲述了该技术在雨、污水管道病害探查中的应用。达到在不采取截流措施的前提下对雨、污水管道外部土体扰动情况及管道内部的完整性情况进行准确判断的目的。     

海湾大桥北引道沥青混凝土罩面设计

结合广东省汕汾高速公路汕头海湾大桥北引道路面加铺工程,分析软基路段过渡性路面的病害,提出沥青混凝土路面罩面结构设计和施工中须注意的问题.     

Haar小波变换在变速器齿轮故障诊断中的应用

推导和证明了Haar小波连续小波变换时间和尺度的周期性，指出这种周期性可以提取出信号中的周期成分，并且使谐波和冲击信号在时间-尺度域中有不同的图形特征。因此根据这些特性可以识别齿轮裂纹产生的冲击和刚度变化，仿真和汽车变速器齿轮故障分析验证了Haar小波变换的有效性和实用性。