薄弱环节对复合材料吸能元件轴向压溃性能的影响综述

薄弱环节设置是复合材料吸能结构设计的关键技术之一,良好的薄弱环节设计可以使复合材料结构在碰撞中产生稳定的渐进压溃从而吸收较多的碰撞能量。文章详细阐述并讨论了复合材料吸能元件薄弱环节的几何特征、引发机制及薄弱环节对复合材料吸能元件轴向压溃性能的影响,并将现有的薄弱环节归纳为七种典型的形式。在此基础上,指出了今后需要进一步研究的课题,包括:应变率效应对薄弱环节引发机制及吸能元件轴向压溃性能的影响;T型薄弱环节的引发机制及其在复合材料圆管中的应用;SMA薄弱环节的原理和设计方法;三维编织复合材料结构元件的薄弱环节和轴向压溃性能。     

海洋混凝土结构

如果设计合理,施工规范,即使在诸如北海或北极那样的恶劣环境下,近海混凝土构筑物也能发挥关键作用.该类近海构筑物大多应用于石油与天然气行业.已经研发了一种技术用于该类承担巨大荷载的钢筋混凝土结构的设计与施工,包括集成设计、规范施工技术及重视施工管理.在近海的海洋环境中有无数的普通混凝土构筑物,如历经了近一个世纪的码头与桥...     

异地分布式桥梁结构远程协同拟动力试验

为了解决现代工程结构日趋复杂化与单个实验室的规模及试验能力之间的矛盾,介绍了桥梁结构远程协同拟动力试验的基本原理、数值积分方法及应用程序的开发。针对目前结构试验中广泛使用的MTS系统,提出了2种不同的控制方法来实现试验程序与MTS控制系统的连接。利用网络化结构实验室系统NetSLab在美国南加州大学及中国3所高校之间进行了六跨桥梁结构的远程协同拟动力试验。试验结果表明：该系统可将异地分布的单一结构实验室通过互联网连接在一起,形成功能强大的网络结构实验室以进行大型桥梁结构系统的远程协同拟动力试验,从而提高综合试验能力,并达到资源共享的目的。     

跨座式单轨路中高架站建筑结构标准化设计

跨座式单轨交通高架车站占有很大比例,高架站中又以侧式站居多。结合重庆轨道交通3号线南延伸段工程,对路中高架3层侧式站建筑结构主要技术参数标准化设计进行讨论。     

山西省综改区大运路桥美学构思与力学研究

山西省综改区大运路桥跨越潇河,向北连接太原中心城区,是潇河产业园区产业发展的主要轴线和对外联系的主要通道,设双向8车道。桥梁方案以水文化为主题,提炼曲线元素,演绎成两跨反对称外倾小拱与一跨斜跨大拱组合而成的闭合螺旋形空间纽带拱桥,跨径布置为(65+110+110+65) m,具有反对称结构的多样与统一、DNA螺旋结构的丰富空间以及黄金分割比例的匀称美观等特点。结构体系选用合理的拱梁组合体系,在拱圈横梁下设置减隔震支座;稳定性和动力性能分析研究表明:由于造型导致的不合理受力仍然在可控范围;综合考虑景观和受力特性,推荐采用矢跨比为1/3.5、外倾角为25°、拱轴线系数为1的设计参数,以及半封闭钢箱梁、钢箱拱、叉耳式吊杆锚固等结构形式。     

Vibration transmission characteristics of composite laminate joints based on power flow北大核心CSCD

[目的]为了研究复合材料层合板连接节点的振动传递特性,提出一种采用有限元功率流法并结合功率流可视化技术的分析方法。[方法]首先,验证用有限元实体单元功率流描述板壳振动的有效性;然后,引入功率流传递率评价指标,提出有限元模型功率流传递率的计算方法,并以导纳功率流法计算结果为参照来验证其有效性;最后,建立嵌入式连接和螺钉连接这2种复合材料层合板的连接模型,计算其功率流传递率曲线和典型功率流矢量图。[结果]对比验证结果表明,2种连接模型的振动传递路径和功率流传递率存在明显差异。[结论]有限元功率流法直观反映了连接结构的振动传递能力及振动能量传递路径,可为复合材料结构设计提供参考。     

Experimental investigation into the effects of air pockets on wave-in-deck loads of offshore structures

In this paper, air entrapment during slamming is an investigation subjected to an experimental method of inquiry, analysed alongside a theoretical approach obtained from previous attempts to address similar matters. The experiment consisted of assembling three different sizes and depths of artificially created pockets underneath the 1:75 deck model of a 76 m × 76 m prototype to encourage air entrapment and study how this entrapped air affects local and global loads. A parametric study is ultimately conducted on the geometry of the pocket, altering area and depth to observe the response to the pressure. Air entrapment effects were observed to reduce the magnitudes of impact pressure inside the pocket while slightly altering the force time histories in x and z-directions. Force magnitudes for global forces are significantly close to the smooth deck results. However, horizontal force data are slightly higher than their corresponding smooth deck due to additional surfaces inside the pocket. In addition, a parametric study of the depth and size of the pocket reveals that pocket depth is the dominant parameter that affects the impact pressure inside a pocket.     

新城路综合管廊工程盾构机适应性分析

盾构法作为城市综合管廊暗挖施工的重要方法，随着城市化的不断深入，所面临的施工现场条件也越来越复杂。通过新城路综合管廊工程的施工重点、难点与应对措施，论证土压平衡式盾构机在珠三角深厚软土层及各种现场工况下的适用性，可为类似工程提供参考意义。     

Planar multibody dynamics of floating Y-method installation system and the lowering of subsea equipment based on finite element modeling

The subsea equipment installation is a complex operation that demands a precise and reliable approach to avoid the accidental losses of lives and equipment damage. The multibody installation system is overwhelmed with the dynamic behavior and responses of the system, which signifies the importance of analysis of the Multibody Dynamic System (MBDS). The modeling of MBDS is challenging and complicated due to the interconnectivity and nonlinearity assigned to them. In this paper, the planar dynamics of a floating multibody system are attained by employing two tugboats and a payload with a contextual offshore installation scenario to be applied in a water depth of over 1500 m. The lifting operation is nine degrees of freedom (9-DOF) multibody model done with the help of two strands and three bodies having 3-DOF each. The coupled equations of motion are established by deploying the Velocity Transformation Technique. The hydrodynamic and two-strand forces are simplified as linear, while the hydrostatic and mooring forces are treated as nonlinear external loads. The numerical solution to the equations for the MBDS is obtained from the Runge Kutta Method of Fourth-Order. Furthermore, the Finite Element Modeling approach discusses the installation operation using Y-method. The results of the proposed numerical model are validated by comparing it with the numerical simulation from OrcaFlex, and the results from both models are found to be in good agreement. The findings of this study will help improve the safe and stable installation of deep-water multibody structures.     

水利与水运工程关于内河重力墙结构的设计差异

水利与水运工程虽同属土木工程范畴的水工建筑物,但由于长久以来服务对象的区别,所属行业分支及管理部门不同,以及两个行业之间缺乏有效沟通,因此设计中间遵循的基本原则及设计思路存在较大差异。对同一结构物设计,其工期、造价往往会有较大区别。以内河重力墙结构为例,对水利与水运工程的设计差异及各自的设计特点进行分析,以期今后的水工结构物设计能够融合两个系统设计理念的精髓,形成统一的设计思路和标准,达到安全、耐久、节约投资的目的。