城市轨道交通U型梁高架系统关键技术研究及创新

结合我国城市轨道交通高架线的应用和发展瓶颈分析,介绍作者及其团队在U型梁高架系统新技术研发和应用方面所取得的主要成果,包括U型梁结构技术、综合降噪技术、与轨道交通各系统的一体化融合技术、施工技术以及技术经济性等内容。以U型梁结构为载体,集成了完备的设计理论和计算方法、减振降噪、节能环保、造型美观、桥面系功能完善、车辆运行安全防护、施工便捷、工期短、显著的经济性等诸多优势,构筑了新一代环境友好型轨道交通高架系统。U型梁高架系统新技术的应用,对促进我国城市轨道交通高架线的健康和可持续发展起到了重要的作用。     

移动模架法桥位制梁施工技术

文中结合武汉天兴洲长江大桥移动模架桥位制梁工程,介绍了移动模架制梁的特点、组成部件、工作原理以及一些关键工艺与技术。在武汉天兴洲长江大桥移动模架制梁施工中,高效快速地完成了制梁任务,所生产箱梁的外形尺寸、外观质量及线形控制完全满足设计和规范要求,取得了良好的效果,经济、环境效益显著。     

基于纽玛克法的变截面波形钢腹板组合箱梁畸变效应分析

为研究变截面波形钢腹板组合箱梁（CBGCSWs）在偏心荷载作用下的畸变效应,忽略波形钢腹板的纵向抗弯刚度,通过建立其微段单元平面内、外力系平衡方程,推导了以畸变角为未知量的畸变微分方程,并采用基于共轭梁理论的纽玛克法进行求解,由此建立了偏心荷载作用下变截面CBGCSWs畸变正应力计算理论。以某大跨变截面CBGCSWs桥为工程背景,运用该理论获得了4种不同工况下组合箱梁角点处畸变正应力理论解,并采用空间有限元方法进行了验证,数值解与理论解吻合良好,表明推导的变截面CBGCSWs畸变计算理论正确且精度足够,可供工程参考。在此基础上,比较了变截面CBGCSWs与对应PC箱梁的抗畸变能力,并探讨了横隔板间距、高跨比、宽跨比及钢腹板形状等因素对变截面CBGCSWs畸变正应力的影响规律。结果表明：用波形钢腹板替代混凝土腹板会较大程度削弱箱梁的抗畸变能力,应当引起足够重视;横隔板间距及宽跨比等参数对畸变正应力影响较大,而高跨比及钢腹板形状等则影响很小。     

约束扭转对汽车车架模态的影响

本文通过三种典型车架模态的实验和计算研究,探讨了约束扭转对汽车车架各阶模态的影响。结果表明:约束扭转对扭转模态影响较大,在研究开口薄壁结构的车架模态时,必需考虑约束扭转的影响,一阶扭转模态对横梁刚度的变化十分敏感。     

预应力混凝土桥梁分析的虚拟层合单元法

通过将预应力束对桥梁结构的作用转化为等效荷载,提出了用虚拟层合单元法分析预应力混凝土桥梁的方法。结合一座具体的桥梁进行了实例分析计算,同时利用有限元通用分析程序SuperSAP进行了对比。结果表明,采用虚拟层合单元法分析预应力混凝土桥梁能够给出令人满意的结果,并且具有划分单元数目少、计算效率高、适应性强的优点。     

大吨位整孔预制箱梁模板设计与施工

杭州湾跨海大桥南引桥上部结构采用50 m整孔预制箱梁,对大吨位整孔预制箱梁施工的底模、外侧模、液压内模、端模结构设计方案和施工技术进行了详细的介绍。     

250000 DWT超大型矿砂船双层底局部短纵桁的设计与优化

基于CCS规范对结构强度有限元计算,分析了超大型矿砂船的双层底中纵桁产生高应力的原因,并根据有限元计算结果提出了解决方案。通过分析比较各方案,最终选择了增加双层底局部短纵桁的形式。重点阐述了设置局部短纵桁的目的、产生的影响,并通过精细网格计算分析,对双层底局部短纵桁的加强方式进行改进,得到更优的节点形式。     

Prediction of the vibratory properties of ship models with realistic structural configurations produced using additive manufacturing

The use of flexible ship models to determine the dynamic behaviour of full-scale ships in waves and to compare the accuracy of numerical predictions has increased in the past few years. Segments attached to a flexible uniform backbone of suitable but simple cross section is the preferred solution. Although such models are relatively easy to manufacture with conventional processes, they do not represent accurately the structural detail, for example, of a container ship. The limitations of conventional manufacturing constraints can be potentially overcome by use of modern technologies such as additive manufacturing. Designing detailed elastic ship models requires the determination of dynamic material properties, in addition to the manufacturer mechanical properties.In this investigation, a detailed but easy-to-implement method is developed, and applied to a uniform container ship-like model, to identify the material properties that are relevant to the calculation of the natural frequencies of 3D printed thin-walled structures. It is demonstrated that modal testing of 3D printed specimens, combined with FEAmodelling, can be used to accurately predict the natural frequencies of much more complex thin-walled structures. This method allows investigators to acquire all information necessary during the design stage of 3D printed structures without having to resort to full material characterisation.     

The design and commissioning of a fully elastic model of a uniform container ship

Experimental hydroelasticity has not followed the rapid evolution of its computational counterpart. Hydroelastic codes have changed significantly in the past few decades, moving to more detailed modelling of both the structure and the fluid domain. Physical models of ships are, even today, manufactured with a very simplified structural arrangement, usually consisting of a hollow rectangular cross section. Appropriate depiction of the internal structural details ensures that properties relevant to antisymmetric vibration are scaled accurately from the real ship to the model. Attempts to create continuous, ship-like structures had limited success, as manufacturing constraints did not allow for much internal structural detail to be included. In this investigation, the first continuous model of a ship with a detailed internal arrangement resembling a container ship is designed, produced using 3D printing and tested in waves. It is demonstrated that the global responses of the hull in regular head waves agree well with theory and past literature, confirming that such a model can represent the behaviour of a ship. Furthermore, it is found that the model is capable of capturing local responses of the structure, something that would be impossible with “traditional” hydroelastic ship models. Finally, the capability of the model to be used to investigate antisymmetric vibrations is confirmed. The methodology developed here opens a whole new world of possibilities for experiments with models that are tailored to the focus of the investigation at hand. Moreover, it offers a powerful tool for the validation of modern state-of-the-art hydroelastic codes. Ultimately, it creates the next step in the investigation of dynamic responses of ship structures, which contribute significantly to accumulating damage of the hull. Better understanding of these responses will allow designers to avoid over-engineering and use of big safety factors to account for uncertainties in their predictions.     

单肢薄壁高墩连续刚构施工稳定性分析

近年来,单肢薄壁连续刚构桥施工失稳破坏频繁发生,损失严重。以西南某桥为背景,先对每个施工阶段进行线性分析,找出各阶段最不利荷载组合,然后分析出最大悬臂阶段各荷载工况、高墩初始缺陷、是否考虑几何非线性等因素对稳定性的影响程度。最后,提出处理建议和措施。