Safety Risk Assessment of Overturning Construction of Towering Structure Based on Cloud Matter–Element Coupled Model

Rapid urbanization has led to a surge in the number of towering structures,and overturning is widely used because it can better accommodate the construction of shaped structures such as variable sections.The complexity of the construction process makes the construction risk have certain randomness,so this paper proposes a cloudbased coupled matter-element model to address the ambiguity and randomness in the safety risk assessment of overturning construction of towering structures.In the pretended model,the digital eigenvalues of the cloud model are used to replace the eigenvalues in the matter–element basic element,and calculate the cloud correlation of the risk assessment metrics through the correlation algorithm of the cloud model to build the computational model.Meanwhile,the improved hierarchical analysis method based on the cloud model is used to determine the weight of the index.The comprehensive evaluation scores of the evaluation event are then obtained through the weighted average method,and the safety risk level is determined accordingly.Through empirical analysis,(1)the improved hierarchical analysis method based on the cloud model can incorporate the data of multiple decisionmakers into the calculation formula to determine theweights,which makes the assessment resultsmore credible;(2)the evaluation results of the cloud-basedmatter-element coupledmodelmethod are basically consistent with those of the other two commonly used methods,and the confidence factor is less than 0.05,indicating that the cloudbased physical element coupled model method is reasonable and practical for towering structure overturning;(3)the cloud-based coupled element model method,which confirms the reliability of risk level by performing Spearman correlation on comprehensive assessment scores,can provide more comprehensive information of instances compared with other methods,and more comprehensively reflects the fuzzy uncertainty relationship between assessment indexes,which makes the assessment results more realistic,scientific and reliable.

Random walk modeling of wake dispersion for the exhaust tower of an underground tunnel in urban area

In this paper, some experimental studies on the impact of effluent from an exhaust tower of an underground tunnel with special construction are reported. By measuring the flow field downstream of the tower in NJU meteorological wind tunnel, some flow characteristics in the make area were established. Based on these, an advanced random\|walk dispersion model was set up and applied successfully to the simulation of dispersion in the wake area. The modelling results were in accordance with wind tunnel measurements. The computed maximum of ground surface concentration in the building case was a factor of 3-4 higher than that in the flat case and appeared much closer to the source. The simulation indicated that random walk modelling is an effective and practical tool for the wake stream impact assessment.

Model experiment on anti-deformation performance of a self-supporting transmission tower in a subsidence area

A large number of high-voltage power transmission towers have recently been constructed in mining areas prone to subsidence. In order to ensure the safety of the transmission towers and the safe operation of transmission systems, it is imperative to carry out research on the anti-deformation performance of transmission towers. In our study, we performed experiments on the anti-deformation performance of a transmission tower in a subsidence area on a scale model with a geometric scale ratio of 1:5 and analyzed the failure mechanism of the tower members. The results show that, when the axial distance between two supports changes, destabilization failure most likely occurs in the members of the bottom transverse layer because some parts of the main diagonal member bars yield under the action of compression. The failure mechanism of the tower members basically coincides with the lever principle.

Modeling of a Demethanizer Tower Using Statistical Tools

Monitoring of industrial plant performance and detection on flaws is important to the successful operation on industrial production units. Malfunctioning equipment can greatly impact plant performance by reducing the efficiency and increasing the production cost. Phenomenological equations cannot properly describe industrial processes. Thus, it is necessary to develop new equations for model industrial operations. The purpose of this study is to develop an empirical model for industrial demethanizer tower which is malfunctioning due to an error in the design in one of its plates. A nonlinear statistical model was designed to predict the pressure variation in the column, and consequently, the flooding conditions. This model was validated using industrial data to predict the maximum loads in the column.

Modeling Research on a Solar Tower Thermal Collection-natural Gas Turbine Power System

塔式太阳能-燃气轮机发电系统发电成本和研发风险都低于常规太阳能热发电系统，同时能克服太阳能随机性、波动性的缺点，可以推动太阳能热发电的商业化进程。为了研究塔式太阳能与燃气轮机发电系统的能量传递与热功转化规律，以及相关结构参数与运行参数对发电系统性能的影响，该文分别建立该系统中压气机、泡沫陶瓷吸热器、燃烧室、透平4部分的传热和热功转化模型，采用Matlab软件平台编程，进行了系统运行仿真模拟，并分析了压比、孔隙率、厚度、吸热器面积、进气温度等对系统性能的影响。研究结果可为系统的设计与运行提供参考。

Research on the Three-dimensional Modeling and Optimization of a Virtual Tower Crane Based on 3DS Max, Solidworks and EON Professional

Three-dimensional modeling of virtual hoisting machinery is the critical works to structure the system of virtual construction, and the foundation to realize intelligent and interactive virtual hoisting. Aimed at enhancing the requests of image quality and stability of the virtual construction scene, taking a tower crane for example. We studied the technology of three-dimensional modeling and optimization of a virtual tower crane, and a method named two-stage model optimization was put forward. This depended on the modeling stage using Solidworks and 3DS Max and the performance optimization stage in EON. The practice of software development indicates that the proposed methods of three-dimensional modeling and optimization could satisfy the performance request of virtual construction system and be popularized to other virtual system.

An Equation of State for Fluids by Applying the Tower-Well Potential Model

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沈阳恒隆市府广场超高层塔楼风荷载分析研究

为了确定高度350.6m沈阳恒隆市府广场塔楼结构设计的风荷载,采用刚性风洞试验与风洞数值模拟相结合的方法分析塔楼的风荷载,风洞试验研究给出楼层剪力与扭矩及风致加速度。采用四种湍流模型进行风洞数值模拟,分析建筑平均风压系数、体型系数、基底剪力及倾覆力矩,并与风洞试验进行比较,得出适用于超高层建筑风洞模拟的湍流分析模型,利用该分析模型的数值风洞模拟技术,分析塔楼13个风向角的风压系数、体型系数和基底剪力,为结构风荷载取值提供依据。研究结果表明:相比于《建筑结构荷载规范》(GB 50009—2012)对近似矩形平面建筑物的体型系数的规定,RSM模型迎风面0.83、背风面-0.56,与规范矩形截面迎风面0.8、背风面-0.6最为接近;RSM模型与试验吻合最好;选取RSM模型来分析超高层等大型复杂结构风荷载,能够得到较为准确的结果。

基于组合赋权云模型的塔台管制系统运行安全评估

随着我国民航业的迅猛发展,空中交通流量不断攀升,机场塔台管制系统的运行安全面临严峻考验,因此,正确识别和评估风险成为有效提高塔台管制系统运行安全水平的重要前提。为精准且有效地完成对塔台管制系统运行的安全评估,构建了基于模糊决策实验室分析法(Decision-Making Trial and Evaluation Laboratory,DEMATEL)网络层次分析法(Analytic Network Process,ANP)熵权法云模型的塔台管制系统运行安全评估模型。首先,通过流程图法并结合人机环管的思想建立塔台管制系统运行安全评估指标体系,并采用模糊DEMATEL法确定评估指标间的相互影响关系,绘制评估指标之间的网络结构图;然后,通过ANP法确定各评估指标的主观权重,采用熵权法确定各评估指标的客观权重,并通过博弈论方法计算评估指标的综合权重;最后,将权重结果与评语层云模型结合使用对各级安全评估指标进行安全评估,通过MATLAB软件完成算例的仿真分析。结果表明:该塔台管制系统运行安全等级在一般和良好之间,仍需采取有效措施对某些风险因素进行控制;同时验证了该模型在塔台管制系统运行安全评估中具有可行性和准确性,对塔台管制系统安全评估具有指导意义。

基于节段模型测力方法的塔式起重机风荷载特性研究

塔式起重机被广泛应用于铁道工程和土木工程施工过程,属于高耸结构体系,风荷载是塔式起重机结构设计的控制性荷载。为完善《塔式起重机设计规范》(GB/T 13752—2017)和《建筑结构荷载规范》(GB 50009—2012)中的塔式起重机斜风向设计风荷载计算方法,解决风向、吊臂、平衡臂位置等因素对塔式起重机遮挡和干扰引起的设计风荷载计算问题。选取平头塔式起重机为研究对象,对塔身、吊臂、平衡臂进行多工况的节段模型测力风洞试验,研究湍流强度、节段干扰和遮挡等因素对塔式起重机节段风荷载特性的影响规律,研究不同风向下节段阻力系数分布规律,对比标准化阻力系数与当前主要规范的异同,进而探讨节段斜风向标准化阻力系数计算方法。研究结果表明湍流强度对节段阻力系数影响较小,可忽略,而平衡臂和吊臂相邻节段的干扰会减小测试节段的阻力系数;在斜风向下,由于吊臂和平衡臂之间存在相邻节段干扰,国内外规范方法的计算值均会大于干扰工况的节段风洞试验值;当前主要国家规范规定的垂直风向塔身、吊臂、平衡臂阻力系数与风洞试验测得的阻力系数值较为接近,基于风洞试验结果给出典型风向的塔式起重机各节段的风荷载系数取值可用于结构设计;基于风洞试验测试结果推导的塔式起重机斜风向风荷载计算方法具有较好的拟合效果。研究成果可推荐相关工程应用,可为相关规范的修改或补充提供参考。

超高桥塔的气弹模型风洞试验及其等效静力风荷载

为研究超高桥塔的气弹模型风洞试验方法及其等效静力风荷载,根据某实际工程中的超高桥塔建立了有限元模型,进行了动力特性计算,进而设计了相应的气弹模型,并开展了风洞试验。在此基础上,开展了超高桥塔风致振动的非线性时程计算,并基于阵风荷载因子法,对比了以位移、内力和应力为单一目标的超高桥塔的等效静力风荷载。结果表明:斜风作用下的桥塔风致振动比较显著,其影响随着风速的增大而愈加明显;当风向角为75°~90°时,超高桥塔将在风速为35~50 m·s^(-1)的区间发生顺桥向的侧弯涡振,但幅值较小;基于应力的阵风荷载因子比基于位移或内力的阵风荷载因子更加稳定,这使得基于应力的等效静力风荷载要优于基于位移或内力的等效静力风荷载,比较适合于超高桥塔。

基于BIM的飞云楼结构古建筑遗产保护模型研究

飞云楼是一项具有深厚历史文化的古建筑遗产,其结构完整性的维护对文化传承至关重要。研究采用BIM技术监测和分析其结构健康状况,为古建筑的保护与维护提供新的方法。分析结果表明,监测桁架的日均变化率高达19.173%,异常监测值达到-43.16,榫卯连接处与地基的日均变化率分别为-15.902%与-20.041%,但异常监测值分别为-46.24与-23.08。对于梁与柱子,异常日均变化率分别为-1.792%与3.594%,梁的异常监测值为17.33,柱子为-51.09。屋顶的异常日均监测值为-62.73,是所有监测部位中最高的,表明屋顶承受的应力或损伤程度可能最为严重。由此可见,该模型为飞云楼的结构性问题提供了预警,指出维护和监控的重点区域,为制定针对性的维修策略提供了依据,同时为其他古建筑的结构健康监测提供了可行的参考。

基于机器学习组合模型的远程塔台管制员情景意识水平

有效识别远程塔台管制员情景意识水平(situation awareness,SA)的主要影响因素,能够更好地为远程塔台管制设计和使用提供参考依据。首先对管制员分别在传统塔台和远程塔台环境下进行数据采集试验,分析两种环境下主、客观指标的差异性。其次,采用假设检验的方法来验证眼动指标作为评价远程塔台管制员SA的可行性。接着基于敏感眼动指标采用K-means聚类和支持向量机(support vector machine,SVM)组合模型分析方法对远程塔台管制员SA水平进行分类识别。结果表明:采用Poly核函数进行模型训练,对SA识别的准确率达到了99.72%。研究结果证实了K-means聚类与支持向量机模型组合模型可作为分析远程塔台管制员SA的有效方法。

保持细节特征的输电铁塔三维网格模型轻量化算法

针对输电铁塔三维网格模型简化后出现模型细节特征大量缺失的问题,以QEM算法为基础,提出了一种保持细节特征的输电铁塔三维网格模型轻量化算法。该算法首先确定了输电铁塔三维网格模型中的细节特征定义,然后提出了输电铁塔细节特征提取策略,并且引入细节特征显著因子和顶点近似曲率因子对QEM算法中的简化代价进行优化。实验结果表明,优化后的算法可以有效保留输电铁塔三维网格模型的重要几何特征和细节特征,避免了简化后模型出现大面积的特征缺失问题,并且相较于普通QEM算法,优化后的算法所简化的模型在最大误差、平均误差和均方差上分别至少下降了39.77%、10.64%和64.99%,实现了输电铁塔三维网格模型的高质量轻量化。

共享铁塔单/双挂载连接件承载性能研究

为研究挂载数量对挂载连接件承载能力和刚度的影响,设计了单挂载与双挂载两种挂载连接件。通过单调拟静力试验研究挂载连接件的承载能力、刚度及其破坏模式,采用有限元软件分析了螺栓直径、钢管宽度、双板件厚度、抗滑移系数和螺栓预紧力对单/双挂载连接件承载力和刚度的影响。结果表明:单/双挂载连接件的破坏模式均为钢管底部加劲肋处断裂,双挂载连接件的极限承载力和初始刚度相比于单挂载连接件分别增加了108.48%和104.27%,可通过加强钢管的上下端部提高连接件的承载力;当抗滑移系数小于等于0.1时,单挂载连接件出现滑移破坏,当抗滑移系数小于等于0.15时,双挂载连接件出现滑移破坏,在其他参数下连接件均未出现滑移破坏;相比于螺栓预紧力和抗滑移系数,螺栓直径、钢管宽度和双板件厚度对连接件的承载力和刚度影响更大;推导出的连接件极限承载力和极限位移计算公式可为同类工程设计提供参考。

密度峰值聚类在塔机损伤诊断中的应用研究

建立塔机有限元模型,获取塔机完好状态和各损伤工况的各采集点的动态位移。提出了两种模型建立方法,基于悬臂梁的双输入单输出模型和基于时域数据的动态双输入单输出模型,对基于时域数据的双输入单输出模型首先利用最小二乘法计算参数初值,进一步利用粒子群优化方法进行参数优化,提高了模型精度。以完好工况的塔机数据为基础,建立基于悬臂梁的双输入单输出模型和基于时域数据的双输入单输出模型,计算参数,建立损伤识别模型,用待检状态的位移数值拟合模型,用两种模型计算出的残差方差做损伤因子,利用密度峰值聚类方法对损伤因子进行分析,实现了对塔机的损伤判定和损伤位置的确定。这种基于密度峰值聚类的诊断方法可对塔机微小损伤进行智能诊断和位置确定,该方法只需要塔机完好状态的数据和待检状态的数据即可自动诊断,解决了塔机损伤识别中损伤数据难以获取,因而无法实现智能训练和诊断的问题。

“万花筒”的新生 深圳妇儿大厦改造案例评述

文章以MVRDV建筑事务所主持设计的深圳妇儿大厦改造项目为例,探讨了建筑在生命周期内其适应性再利用的可能性。通过体量、结构、立面三类改造策略的运用,建筑师对塔楼裙房模式的高层建筑类型进行了挑战,创造了积极的城市界面与公共空间。该项目为改革开放初期同类型高层建筑的功能置换与空间再生提供了一个范例。

多源LiDAR和UAV影像的塔式建筑物三维建模方法

塔式建筑物由于立面结构复杂,使用单一数据源进行三维建模时容易出现部分区域空洞、纹理拉花等情况。为解决此问题,本文提出一种将无人机(Unmanned Aerial Vehicle,UAV)影像、机载LiDAR数据和手持LiDAR数据进行配准融合的塔式建筑物三维建模方法。以云南省玉溪市新平县的五彩云楼为例,使用UAV和手持激光扫描仪作为数据采集设备,首先分别采集塔式建筑物的UAV影像、机载LiDAR和手持LiDAR数据,然后基于摄影测量原理生成UAV影像的点云,其次基于最近点迭代算法方法将三种数据进行配准融合,最后通过构建不规则三角网表示其三维模型。实验结果表明:将多源LiDAR和UAV影像点云配准融合后生成的三维模型结构更加完整,避免了单一数据源构建三维模型存在的空洞问题。

基于代理模型的输电塔半刚性节点弯矩-转角曲线预测方法

为了准确、高效地评估输电塔半刚性节点的力学特性,提出了一种基于代理模型的输电塔半刚性节点弯矩-转角曲线预测方法,通过引入代理模型方法近似半刚性节点几何尺寸与极限抗弯承载力、初始转动刚度之间的函数关系,建立具有较高精度的预测模型,进而结合Kish-Chen幂函数模型拟合输电塔半刚性节点的弯矩-转角曲线。结果表明,提出的基于代理模型的输电塔半刚性节点弯矩-转角曲线预测方法能减少实验和数值模拟的成本,较好地模拟输电塔半刚性节点实际受力-变形情况,为输电塔半刚性节点的工程设计和理论研究提供了参考。

海上漂浮式风电机组塔筒优化方法研究

为适应复杂多变的海上环境,高效利用风资源、减少用钢成本,开展漂浮式风电机组塔筒的结构优化设计。以船载风电机组为研究对象,引入漂浮式基础的动态响应,作为影响塔筒弯曲变形的重要约束条件。在保证风电机组稳定功率输出的前提下,以质量最轻为优化目标,以塔筒构造要求和规范为基本约束条件,建立漂浮式基础风电机组塔筒的数值优化模型,并利用遗传算法完成了模型优化。结果显示,在保证风电机组稳定性和正常功率输出要求下,塔筒的质量降低了35%,刚度提高了25%。