点支式夹层玻璃板受弯承载性能的有限元分析

点支式夹层玻璃具有良好的安全性能,当与中空玻璃结合使用时可兼具节能、安全的特性.现行规范尚未考虑夹层玻璃PVB夹层的抗剪作用,似乎显得较为保守.本文从PVB层的性能出发,使用有限元方法对点支式夹层玻璃板的受弯承载性能进行了分析,数值计算与现有试验结果吻合得较好.结果表明,在短期荷载作用下,规范设计方法显得较保守,本文建议虽然在短期荷载作用下适当的考虑PVB层的作用,但考虑幕墙工作环境,设计不宜考虑其贡献.     

四边简支夹层玻璃受弯承载力试验研究及有限元分析

通过拉伸试验和剪切试验,得到了PVB胶片的材料性能参数,并通过受弯承载力试验,研究夹层玻璃的受力特点,进而分析PVB胶片的厚度、温度变化对其承载能力的影响。试验结果表明：胶片对夹层玻璃的受力性能有显著影响,且胶片的粘结作用不能忽略,随着温度的升高,其承载力降低。运用ANSYS有限元软件对试验模型的受力性能进行数值模拟,有限元计算结果与试验结果吻合较好。试验结果和有限元分析结果均表明：现行国家规范关于夹层玻璃位移的计算值大于试验值和有限元分析值,计算偏于保守。     

胶层厚度和耐湿老化对夹层玻璃中PVB胶与玻璃界面粘结性能的影响

夹层玻璃的耐久性和安全可靠性与其界面粘结性能密切相关。本文首次提出了十字交叉法测量夹层玻璃中PVB胶与玻璃的界面拉伸和剪切粘结强度,分别研究了加载速度效应、PVB胶层厚度效应和湿度老化等的影响。结果表明:测量夹层玻璃中PVB胶与玻璃粘结强度的加载速度应选取5mm/min。当胶合层厚度相同时,界面拉伸粘结强度高于其剪切粘结强度,PVB胶层厚度越大,其拉伸粘结强度和剪切粘结强度都逐渐越低。单层PVB胶片与玻璃之间的界面拉伸粘结强度最大值为11.49MPa。耐湿老化对玻璃与PVB胶的界面粘结强度影响不大,即使老化60天后,其拉伸粘结强度也仅下降12.3%。     

中空玻璃热工性能有限元分析

在现代化的建筑中,越来越多地采用门窗与玻璃幕墙,而门窗、玻璃幕墙是建筑的主要耗能部位,中空玻璃又是门窗与玻璃幕墙的重要组成部分,其直接影响到建筑的能耗。本文通过对中空玻璃的热工性能有限元分析,并计算了各种不同类型的中空玻璃综合传热系数U,为门窗和玻璃幕墙热工设计提供了参考依据。     

夹层玻璃金属植入节点抗拉拔性能研究

结构玻璃一般采用夹层玻璃。对于夹层玻璃构件,可采用金属植入节点来实现构件间的连接,但目前缺少成熟的金属植入式节点承载力设计方法。为此,设计并制作了5个采用离子性中间层的夹层玻璃金属植入节点,通过静力试验研究金属植入节点的抗拉拔性能,得到了节点的破坏形态及节点在拔出过程中的荷载-位移曲线。试验中节点破坏由胶片脱黏控制,且具有一定的延性破坏特征。通过理论推导得到了考虑胶片拉伸及剪切变形协调的胶片内力计算方法和节点承载力计算方法,将拉伸黏接面脱黏时定义为金属植入节点的承载能力极限状态,建议设计时应保证外层玻璃具有足够的强度。通过试验结果与理论计算结果进行对比,验证了所提出承载力计算方法的合理性。     

复合材料层合板的层间应力有限元分析

本文研究复合材料层合板的层间应力,以经典板理论为基础,考虑横向剪切变形和层间相互挤压,构造每一铺层与层间胶层的位移场,采用有限元方法,应用广义势能原理确定位移场中的待定系数,从而确定层合板的位移场和应力场。采用ANSYS计算,计算结果显示,这种解法克服了经典层合板理论的缺点,提高了层间应力的计算精度。     

Free vibration analysis of laminated FG-CNT reinforced composite beams using finite element method

In the present study, the free vibration of laminated functionally graded carbon nanotube reinforced composite beams is analyzed. The laminated beam is made of perfectly bonded carbon nanotubes reinforced composite (CNTRC) layers. In each layer, single-walled carbon nanotubes are assumed to be uniformly distributed (UD) or functionally graded (FG) distributed along the thickness direction. Effective material properties of the two-phase composites, a mixture of carbon nanotubes (CNTs) and an isotropic polymer, are calculated using the extended rule of mixture. The first-order shear deformation theory is used to formulate a governing equation for predicting free vibration of laminated functionally graded carbon nanotubes reinforced composite (FG-CNTRC) beams. The governing equation is solved by the finite element method with various boundary conditions. Several numerical tests are performed to investigate the influence of the CNTs volume fractions, CNTs distributions, CNTs orientation angles, boundary conditions, length-to-thickness ratios and the numbers of layers on the frequencies of the laminated FG-CNTRC beams. Moreover, a laminated composite beam combined by various distribution types of CNTs is also studied.     

钢筋混凝土框架结构层间隔震有限元分析方法

层间隔震是当前抗震防护技术中的热点问题之一。本文首先给出钢筋混凝土弹性矩阵的等效计算方法以及普通叠层橡胶支座(RB)、铅芯橡胶支座(LRB)等效弹簧单元刚度矩阵的计算方法;接着采用ABUQUS软件建立框架数值模型并设置相应的边界条件;最后以一幢8层钢筋混凝土框架结构建筑为例,通过数值计算,比较分析了以RB橡胶支座和LRB橡胶支座作为隔震装置的两种层间隔震方案的优劣。计算结果表明:与传统结构相比,两种层间隔震方案都能大大降低上部结构的加速度、位移响应;上部结构运动近似于刚体运动,抗震效果明显。总体上看,LRB隔震方案优于RB隔震方案。本文方法对钢筋混凝土层间隔震技术的数值模拟研究有一定的意义。     

Finite element modelling of structural stainless steel cross-sections

Stainless steel's characteristic nonlinear, rounded stress–strain behaviour requires accurate recognition in numerical modelling. Its response to cold-working is far more pronounced than that of ordinary carbon steel and hence appropriate modelling of the cold-worked corner regions is very important. Despite the importance of geometrical imperfections, their measurement is not a very common practice and assumed models are generally adopted in numerical investigations—often without proper verification. This paper investigates all important aspects for modelling stainless steel cross-sections through carefully designed parametric studies. Different cross-section types have been considered and the numerically obtained load–deformation responses have been compared with selected experimental results; the findings form the basis for specific guidelines. These proposals have been verified by application to all available stainless steel stub column tests obtained from different sources. The predicted numerical results have shown excellent agreement with those obtained experimentally.     

Calibrating a high-fidelity finite element model of a highway bridge using a multi-variable sensitivity-based optimisation approach

This article presents the implementation of a calibration procedure for a finite element (FE) model of a state highway bridge using sensory data measured on the bridge. The objective is to modify the high-fidelity FE model of the bridge so that its dynamic behaviour matches, as closely as possible, that of the bridge under analysis. The bridge under investigation is a steel–concrete composite bridge that is instrumented with a wireless monitoring system to collect its vibration response under ambient vibrations. A detailed three-dimensional FE model of the bridge was developed to represent the bridge as realistically as possible. The detailed modelling can minimise the amount of uncertainty in the model and the number of parameters that require updating. A multi-variable sensitivity-based objective function is used to minimise the error between the experimentally measured and the FE-computed modal characteristics. An iterative optimisation approach has been undertaken to find the optimum structural parameters of the FE model that minimise the selected objective function. It is shown that developing a high-fidelity FE model may help simplify the model calibration process for a large structure, which is contrary to conventional thinking on the subject.     

浅析建筑夹层玻璃环境性能不合格原因及改进建议

夹层玻璃是安全性能最优的玻璃,但目前存在生产能力良莠不齐的情况,导致市场上有大量的不合格产品,且不合格情况主要出现在环境性能方面。本文通过对工厂“人、机、料、法、环”等可能导致夹层玻璃不合格的环节进行分析,提出相应的改进方法及建议,以期帮助夹层玻璃生产企业减少不合格品的产出。     

夹板式夹层玻璃抗风压性能试验研究

夹板式夹层玻璃具有良好的安全性能,已得到了越来越广泛的应用。现有关于夹板式夹层玻璃的研究还比较有限,国内现行规范尚未规定夹板式夹层玻璃的设计。本文从夹板式夹层玻璃的抗风压性能出发,以某夹板式玻璃幕墙工程抗风压性能试验为基础,研究了不同压力差对夹板式夹层玻璃作用下的挠度分布规律,并将试验结果与规范JGJ102—2003的点式玻璃计算方式的结果进行对比,并对夹板式夹层玻璃的挠度计算进行了探讨,为今后规范的进一步完善、修订及夹板式夹层玻璃在玻璃幕墙工程中的应用提供了试验依据。     

考虑接缝影响的机场刚性道面的有限元分析

以Marc有限元软件为工具,对道面面层和接缝用板单元进行模拟,考虑面层和基层之间的界面接触,建立了基于＂地基—道面结构—飞机轮载＂的相互作用的足尺9块板水泥混凝土道面三维有限元模型,应用该模型,计算了飞机当量单轮荷载作用下刚性道面结构的力学响应,得出道面各结构层模量对板底应力的关系。     

建筑玻璃风荷载与塑料窗型材杆件风荷载的探讨

在建筑围护结构中,不能忽视外窗建筑玻璃的风荷载计算。本文从《建筑玻璃应用技术规程》三个版本对玻璃的风荷载设计条款和计算公式的区别方面,探讨了外窗杆件的风荷载与建筑玻璃的风荷载计算的关系,强调在进行外窗风荷载计算时,不能忽视建筑玻璃的风荷载的计算。     

某电厂板仓钢支架结构有限元分析与验算

对某电厂钢板仓钢支架结构进行有限元分析.依据相关规范对支架结构进行验算.对支架结构提出了设计修改方案.有限元分析和计算表明,改进后的支架结构强度、刚度、稳定性符合要求.     

土—基础共同作用分析的有限元/无限元耦合方法模型研究

为考虑土—基础共同作用,建立了有限形无限元耦合方法分析模型。通过对同一结构体系分别应用有限元理论和有限形无限元耦合方法比较,研究了有限形无限元耦合体系中有限元范围在水平与竖向区域的不同取值对计算结果的影响,从而确定了有限元区域的计算范围。结果表明,有限形无限元耦合方法对于研究共同作用问题具有较高的精度和显著的经济性。     

高填方地基位移和应力分布的有限元分析

以大型通用有限元软件ANSYS为工具，对高填方地基的位移和应力分布进行了数值计算与模拟，探讨并分析了其位移和应力分布的规律。     

Finite element modelling of plate girders with web openings

This paper is concerned with a finite element model to predict the behaviour and ultimate load of plate girders with web openings. The finite element package is used to model the plate girders with web openings. Accuracy of the model is assessed by applying it to plate girders tested earlier by other researchers. Comparison of analytical results with the available experimental results for yielding patterns, ultimate load values and load–deflection relationships show good agreement between the finite element and experimental results thus validating the accuracy of the proposed model. The proposed finite element method was extended to carry out a parametric study. The study covered parameters such as web slenderness and flange stiffness.     

Finite element modelling of the pyrolysis of wet wood subjected to fire

The modelling of the pyrolysis of wet wood provides more realistic fire scenarios for structural fire design by taking into account variable thermal properties of wood which are beyond the scope of conventional structural fire design codes. The proposed numerical methodology has been written in MATLAB environment. A 2D nonlinear finite element analysis (FEA) is performed to model the pyrolysis of wet wood subjected to high temperature. The varying of thermal proprieties of wood are discussed from the point of view of changes of structure and chemical composition under fire condition. The validity of the model is established by comparing the predicted results with results from fire resistance tests presented in literature. Qualitatively, the model provides good agreement with the experimental data. It is shown that the model can handle layers of a wooden composite structure. Temperature profiles at different points in the wood sample and the two-dimensional charring depth of Laminated Veneer Lumber (LVL) panels are calculated and compared with experimental data.     

非饱和土水气两相渗流有限元数值模型

根据非饱和土水气两相渗流理论,用Galerkin法建立了用以计算非饱和土水气两相渗流流场的有限元计算模型,编制了三维有限元计算程序,并介绍了该计算模型在可挥发污染物抽气曝气组合清除法中的应用。