Resisting system and failure modes of masonry domes

The research synthesized in this paper focused on ultimate strength, structural safety assessment, and collapse of masonry domes. Activity was directed at analyzing the relationships between safety factor and geometry, and carrying out research targeted at reducing the incidence and severity of structural failures in cultural buildings. This paper shows that the resisting system of a masonry dome is not the two-dimensional shell, but a one-dimensional mechanism that derives from the splitting of the shell and drum. The resisting system, whose geometry depends on the dome shape and brick or stone pattern, may include the lantern and/or the masonry constructions around the drum.Well-known domes taken from architectural cultural heritage are used to exemplify the pivotal role of geometry and construction techniques in providing ultimate strength. These examples also show the importance of considering the architectural design of the time, in structural analyses.The results found in the paper suggest how to provide masonry domes with adequate safety, using the minimal level of structural intervention; in particular, without altering the way the building reacts to applied loads. Hence, the paper helps understand how to reduce the amount of structural work, which, in turn, guarantees conservation and restoration, as well as safeguarding.The conclusions are devoted to analyzing which observations are valid for seismic assessment and how the other observations have to be modified for seismic actions.     

拉索穹形屋盖结构计算分析

采用有限元法对拉索穹形屋盖结构进行几何非线性静力计算，并对该结构的特点作了分析讨论．     

现代高炉高风温关键技术问题的认识与研究

提高风温可以有效降低高炉燃料消耗,促进高炉生产稳定顺行,是绿色低碳炼铁技术的重要发展方向之一。研究了热风炉热量传输过程和传热特性,通过传热学机理的研究解析,阐述热风炉加热面积与风温之间的关系,提出提高热流通量以改善热风炉传热的观点。研究了热风炉理论燃烧温度、拱顶温度和风温之间的关系,介绍了利用低热值高炉煤气和回收热风炉烟气余热,通过耦合预热和能量梯级利用的技术方法,实现高风温的技术创新及实践。提出了实现热风炉智能化操作的技术要素,论述了合理控制拱顶温度和抑制NO_x大量生成的工艺方法,以及有效预防热风炉炉壳晶间应力腐蚀的技术措施。指出实现低热值煤气的高效利用和高值转化,提高风温、降低燃料比和CO₂排放,是未来高炉炼铁的关键共性技术。     

真正的福斯特建筑：国会大厦

德国国会大厦随着它的修复和改造的完成,正逐渐成为新首都柏林民室的象征。在此,设计师诺曼福斯特展示了一个寻求历史与未来、旧与新、民主与政权相平衡的很好的设计实例。     

Buckling and large deformation behaviour of composite domes compressed between rigid platens

This paper aims at describing the large deformation behaviour of transversely loaded composite spherical domes. Two distinctive glass fabrics, woven and knitted, embedded in the same thermoplastic matrix, polypropylene, were utilised to produce the composite domes. The doubly curved shells with different number of plies and orientations (radius to thickness ratio in the range of 22–53) were compressed between two rigid flat platens. Load–displacement responses and deformed patterns were examined using experiments and numerical simulations. Because of the large deformation involved, a non-linear stress analysis technique has been adopted to simulate the responses. The loaded domes, both woven and knitted, display rolling-plastic hinge post-buckling response after initial buckling. Some interesting results due to orthotropy have been presented along with comprehensive material characterisations. The numerical simulations have produced very promising matching results.     

潮流水轮机导流罩的水动力设计

为了提高潮流水轮机的效率,参照风力机扩散器原理设计了一种适用于竖轴直叶片水轮机的导流罩.主要考虑潮流工作流场对称性的特点,提出了二大类型6种导流罩设计模型方案;应用Fluent软件进行水动力性能计算,确定流速大,阻力小的S3为最优型线;在导流罩出口位置增加对称的扩张门,可以进一步提高导流罩内流场的流速和稳定性;模型实验验证了S3型导流罩设计模型的有效性,加导流罩后轮机功率系数曲线整体上升,峰值可提高39%.该设计研究为导流增强型潮流水轮机的研究和实践提供了理论基础.     

双曲拱坝计算机辅助施工放样与图形处理

对变圆心变半径双曲拱坝的施工放样及计算机图形处理提出了一种通用算法，根据此算法计算拱坝施工所需要的工程数据并开发出拱坝图形处理软件，用于拱坝设计和施工．     

天线罩电磁特性的仿真分析

论述了天线罩结构参数对天线方向图的影响．采用几何光学法和射线跟踪法,分析了天线在加罩与不加罩时方向图特性的变化规律．用计算机进行了仿真分析,仿真结果说明该分析方法适用于多种天线罩电磁特性的分析,同时该方法对天线罩电磁特性的评估是有效的．     

索穹顶结构的计算分析和节点与构件控制

回顾了索穹顶结构的发展历史，并介绍了索穹顶结构的形态、特性和优点；对其成形进行了分析和设计；用非线性有限元理论对索穹顶结构进行一些非线性分析；讨论了索穹顶结构在实施技术中的节点设计、整体张拉控制技术问题；最后展望了索穹顶结构的发展应用前景。     

摩擦摆支座在K8型单层球面网壳结构中的隔震研究

为获得应用摩擦摆支座(FPB)单层球面网壳结构的抗震性能,将摩擦摆支座精细化有限元模型应用到跨度为80 m的K8型单层球面网壳结构中,对两种支承形式的网壳结构施加相同的地震波.依据结构杆件和节点动力响应对摩擦摆支座的隔震效果进行分析,讨论了在水平和竖向地震动时摩擦摆支座的摩擦系数和曲率半径对单层球面网壳地震响应的影响规律.结果表明:随着地震动强度的增强,摩擦摆支座的最优摩擦系数也随之增加;摩擦摆支座曲率半径越大网壳结构的地震响应越小.在上述研究基础上,对单层球面网壳结构如何选择摩擦摆支座进行了一些讨论.