船闸反弧门设计要点

反弧门设计边界条件复杂、计算参数难以选定,目前缺乏相关设计指导文献,设计难度大。通过大藤峡船闸反弧门相关的模型试验研究,并总结葛洲坝、三峡和大藤峡船闸反弧门设计经验,得出可有效抑制空化现象的廊道体形;依据闭门速度快慢选取动水荷载系数;采用全包板门体结构和流线型底缘可减小水流扰动,改善流态,减小气蚀破坏;启闭力计算时需要考虑水柱力和水阻力等设计要点和合理化建议。     

大坞电动绞车卷筒轴承损坏原因分析及解决方案

文章对大坞电动绞车卷筒轴承进行了受力分析，确定钢丝绳卷筒两侧的卷筒轴承受力不均匀是造成卷筒轴承易损坏的原因，提出了解决方案。并对电动绞车的使用、维修提出了建议，供同行借鉴。     

深水大跨码头结构研究

通过对我国港口现状的分析,对高桩码头上部结构改革状况的研究,提出了适应深水大跨要求的悬链线拱式纵梁码头结构型式。该结构能充分利用拱结构的跨越能力和钢筋混凝土的抗压性能,大幅度增加码头的排架间距,减少水下工程量,进而降低工程造价。与上海港洋山港区三期工程的普通纵梁结构相比,该结构排架间距可增大到28 m,基桩数量和水下施工工程量明显减少,工程造价降低23%。     

高桩承台靠船墩群桩水平受力简化分析

在船闸及河道中广泛应用的靠船墩、防撞墩等高桩承台结构承受较大的水平荷载,多采用群桩基础,而群桩受力分析比较复杂,有必要进行简化研究。以高桩承台靠船墩桩群为研究对象,分析了最不利工况,即撞击力作用通过靠船墩角点,且呈切线方向。通过典型的钢管桩三桩墩台进行分析,进一步推广到其他群桩结构,推导出简化公式。     

半船移位受力分析及运动仿真研究

通过ADAMS软件对运用垂直半串连造船法建造的半船移位到指定坞位的全过程进行仿真,优化运动轨迹。使用FLUENT、MAXSURF等软件系统建立半船实体受力分析模型,对半船移位过程中拖轮的牵引力和转矩随时间的变化进行计算,为实际移位提供了理论数据。     

Influence of tyre–road contact model on vehicle vibration response

The influence of the tyre–road contact model on the simulated vertical vibration response was analysed. Three contact models were compared: tyre–road point contact model, moving averaged profile and tyre-enveloping model. In total, 1600 real asphalt concrete and Portland cement concrete longitudinal road profiles were processed. The linear planar model of automobile with 12 degrees of freedom (DOF) was used. Five vibration responses as the measures of ride comfort, ride safety and dynamic load of cargo were investigated. The results were calculated as a function of vibration response, vehicle velocity, road quality and road surface type. The marked differences in the dynamic tyre forces and the negligible differences in the ride comfort quantities were observed among the tyre–road contact models. The seat acceleration response for three contact models and 331 DOF multibody model of the truck semi-trailer was compared with the measured response for a known profile of test section.     

The role of the contact geometry in wheel–rail impact due to wheel flats: Part II

A classification of wheel flats according to the different stages of their growth is given, along with the characteristic features of the dynamic wheel–rail interaction for each category. Mathematical expressions and frequency spectra of the corresponding wheel mass trajectories are derived. Difference is made between the subcritical and the transcritical speed regime. A criterion is derived for contact loss for worn flats. Simulations show that the dynamic wheel–rail interaction is governed by the track stiffness for low train speeds or long flat lengths; for high speeds and/or short flat lengths the interaction is governed by the inertial properties of the wheel and the rail. For a given flat geometry, nonlinearities in the relationship between the impact magnitude and the train speed occur in the stiffness-dominated speed domain, whereas this relationship is approximately linear in the inertia-governed domain. In the latter domain, the impact magnitude is found to be linearly dependent upon the maximum trajectorial curvature or inversely linearly dependent on the minimum circumferential wheel tread curvature. The above relationships are valid for the subcritical speed regime, in which no contact loss occurs. Different contributions from the literature are compared with respect to the established relationship between impact magnitude and speed. Significant differences are found, due to insufficiently defined parameters and conditions. Conditions are derived for a consistent application of the so-called equivalent rail indentation in experiments with wheel flats, and the indirect strain registration method for measuring dynamic wheel–rail contact forces is reviewed.     

磁悬浮列车的涡流制动问题

介绍了磁悬浮列车制动的一般问题以及德国TR07磁悬浮列车中涡流装置的供电电源、制动装置、有关的计算与试验曲线。最后介绍了用“迎流”有限元法求解制动力的方法。     

简支梁桥上无缝道岔温度力与位移影响因素分析

将道岔、梁和墩台视为一个系统,建立简支梁桥上无缝道岔的有限元模型。根据变分原理和“对号入座”法则建立有限元方程组。以铺设一组43号道岔的18跨32 m混凝土简支梁桥为例,研究影响简支梁桥上无缝道岔受力与位移的因素,如支座布置形式、轨温变化幅度、梁温差、扣件阻力、道床阻力、限位器间隙、岔枕刚度、限位器位置、梁跨长度和桥墩刚度等。计算结果表明,简支梁桥上无缝道岔在温度荷载作用下,钢轨温度力在限位器处和限位器前梁端处同时出现两个峰值;与桥上无缝线路相比,桥上无缝道岔桥墩处的最大受力显著增大;当梁与导轨同向伸缩时,岔区内钢轨位移较大;限位器应布置在梁跨中部;限位器间隙对桥上无缝道岔的受力与位移有双重影响;岔区内钢轨的受力与位移随桥墩刚度增大而减小;岔区内采用较大的扣件阻力和道床阻力,岔区外采用较小的扣件阻力和道床阻力,可以降低钢轨附加温度力。     

波浪力作用下钢管桩施工平台随机动力响应分析

采用有限元分析程序提取了平台的各阶自振频率,以有效模态质量参与系数作为模态选择的依据,对随机波浪力作用下考虑结构与水耦合的的动力响应进行计算,并分析了附连水质量及动水阻尼对结构随机动力响应的影响。通过施工平台静、动力计算结果的比较,建议在进行施工平台的设计时,应充分考虑到波浪力的动力效应。