声屏障夹芯板隔声性能的研究

通过数值模拟对不同厚度、不同芯材密度的金属面夹芯板隔声量进行计算,并与试验值作比较,验证了软件模拟的可行性.利用数值模拟方法分析钢板的厚度,芯材的厚度、密度与隔声量之间的关系,以共振频率为分界点,拟合金属面夹芯板隔声量的计算公式.比较表明,试验值与计算值误差较小,可以为工程实践提供指导.     

彩钢复合夹芯板建筑体燃烧性能试验研究

采用大尺度实体火试验方法,综合分析比较了岩棉、B1级聚氨酯、B1级聚苯乙烯彩钢复合夹芯板建筑体的试验现象、火焰蔓延特性、环境温度等燃烧特性试验数据。结果表明,岩棉芯材彩钢复合夹芯板相对安全,聚氨酯芯材彩钢复合夹芯板建筑体因板缝拼接处采用可燃软质泡沫存在安全隐患,聚苯乙烯芯材彩钢复合夹芯板在试验过程中出现全面燃烧,火灾危险性很大。     

格构腹板增强泡桐木夹芯复材板的弯曲性能试验

采用真空导入工艺,制备了格构腹板增强泡桐木夹芯复材板。对不同格构腹板厚度和不同腹板间距的试件进行四点弯曲试验,研究其破坏模式、跨中应变和跨中挠度情况。试验结果表明:增加腹板厚度能有效提高夹芯板的极限承载力,提高幅度随腹板厚度的增加而减小;减小格构腹板间距也能提高夹芯板的极限承载力,提高幅度随格构腹板间距的减小而减小。采用铁木辛柯梁理论,考虑弯曲和剪切变形的共同影响,推导出板材跨中挠度计算式;采用经典夹芯梁理论预估了试件的受弯极限承载力,挠度和承载力的理论值与实测值均吻合较好。     

酚醛泡沫彩钢夹芯板防火性能研究

通过实验对酚醛泡沫彩钢夹芯板的防火性能进行了研究,重点介绍了彩钢夹芯板常用芯材燃烧性能对比实验研究、酚醛泡沫彩钢板防火性能实验研究。试验证明,以酚醛泡沫为芯材的酚醛泡沫彩钢夹芯板具有很好的防火性能。     

格构增强泡沫夹芯复合材料单向板弯曲疲劳研究

作为近年来兴起的的新型材料,格构增强泡沫夹芯复合材料具有轻质高强的优势,其通过在芯材之间加入格构腹板有效地提高了复合材料单向板的抗弯性能。本项研究对格构增强型泡沫夹芯复合材料单向板的弯曲性能进行了静态试验和疲劳试验,并应用统计学理论与累积损伤模型对疲劳试验结果进行了分析,结果表明其疲劳统计寿命服从Weibull分布,并以此为基础建立了在一定可靠度下的双对数疲劳方程和单对数疲劳方程。累积损伤模型能较好地反映单向板损伤发展的过程,在此基础上完善了格构复合材料单向板的疲劳寿命方程。研究结果表明,格构腹板的加入对提高泡沫夹芯复合材料单向板的弯曲疲劳性能有重要作用。     

新型混合芯材复合材料夹芯板受弯性能试验研究

研制一种真空成型工艺制作的基于轻木-泡沫混合芯材的复合材料夹芯板。采用四点弯曲力学性能试验研究复合材料夹芯板的受弯破坏形态以及芯材组分对复合材料夹芯板弯曲力学性能的影响。结果表明,复合材料夹芯板的破坏模式不同于花旗木板,表现为GFRP腹板的剪切破坏。复合材料夹芯板的抗弯承载力及刚度大于花旗木板;夹芯板提高芯材和GFRP的利用效率;随着混合芯材夹芯板芯材成分比例的不同,峰值挠度基本相同,但随着花旗木芯材比例的减小,峰值承载力和抗弯刚度降低。     

爆炸荷载作用下夹芯板的动力响应研究

为了得到夹芯板在爆炸荷载下的动力响应,采用试验、能量法和有限元分析方法对其进行研究.首先,介绍一种可用于夹芯板抗爆性能研究的试验系统装置及其试验结果;其次,将夹芯板的变形过程分为3个阶段,假定夹芯板通过芯材的压缩变形、面板的拉伸和弯曲消耗爆炸荷载作用到夹芯板上的能量,通过能量平衡方程得到夹芯板的变形量;最后,采用有限元...     

建筑用绝热金属面夹芯板抗弯承载力的试验研究

金属面夹芯板是很常用的建筑保温隔热材料。目前,最新夹芯板国家规范仅包括岩棉和聚氨酯的承载力设计公式,对其他面夹芯板没有涉及。通过对48个不锈钢、铝板、秸秆面夹芯板抗弯试验和27个材料性能试验,得到各种芯材的基本材料性能以及不同夹芯板的抗弯承载力,为统一抗弯承载力公式的推导打下基础。     

岩棉夹芯板的耐久性

以聚苯乙烯、聚氨酯为芯材的金属夹芯板在建筑工业中得到广泛应用。但由于其芯材耐火性差，限制了其在防火要求较高建筑中的应用，而且在国内、外施工和使用中已发生数起大型火灾造成巨大经济损失。因此，国外先后开发和发展了具有良好力学性能和耐火性能的岩棉夹芯板。近...     

彩钢夹芯板房和帐篷的防火间距研究

对灾区过渡安置点搭设板房常用的彩钢聚苯乙烯(EPS)夹芯板和聚氨酯(PU)夹芯板结构、防火性能进行分析,同时对安置点内帐篷材质、燃烧性能进行介绍。在彩钢夹芯板房火灾实验基础上,用火灾案例和FDS模拟方法验证分析实验结论,研究确定彩钢夹芯板房和帐篷的防火间距。     

Experimental and numerical study of temperature developments in PIR core sandwich panels with joint

This paper presents the results of an experimental and numerical investigation of temperature developments in sandwich panels consisting of steel sheeting and polyisocyanurate (PIR) core. Fire experiments were carried out on individual PIR sandwich panels and PIR sandwich panels with joint. The fire test results were used to validate a temperature dependent thermal conductivity model for PIR, through numerical heat transfer modelling using the general finite element package ABAQUS. The fire test results indicate that the temperatures at the joint on the unexposed side of a sandwich panel is initially lower than that on the panel. However, at high temperatures, the ablation of PIR core creates large gaps up to 25 mm. Due to high radiation within the gap, the joint temperature becomes much higher than the panel temperature. The results of a numerical parametric study indicate that if the joint gap can be controlled to be no greater than 5 mm, the joint and the panel temperatures on the unexposed surface would be similar. Joint gaps of 10 mm or greater would result in joint temperatures much higher than panel temperatures and would reduce the sandwich panel system insulation performance of less than 60 min even though the panel may be able to reach much longer standard fire resistance rating.     

110 kV高压电缆着火过程数值模拟研究

为了研究综合管廊局部空间内电缆接头内热源作用下的着火过程,通过运用数值模拟软件FDS三维传热和热解模型对110 kV高压电缆接头着火过程建模分析.研究了内外热源对电缆着火过程的不同影响,分析了不同运行状态下的温度分布情况,对比了不同缆芯材料的热传导作用对电缆着火过程的影响.结果表明,正常运行和短时过载状态下,电缆的火灾...     

Hybrid Progressive Damage Prediction Model for Loaded Marine Sandwich Composite Structures Subjected to a Fire

The risk of fire, and of fire-related structural degradation, represents an ever present challenge to the safe design of marine sandwich composite structures. Current state-of-the-art fire analysis and damage assessment tool has ignored the coexistence of discrete (delamination) and continuum damage in a sandwich composite structure after a fire exposure. To capture the synergistic interaction between the discrete and continuum damage and their compounding effects to the final failure, a fire damage assessment tool for a marine composite sandwich structure was developed by integrating the 1D fire model of a composite sandwich panel with a hybrid progressive damage prediction module within the LS-DYNA3D computational framework. The 1D fire model for a combustible skin and decomposable core was employed to characterize the temperature and mass dependent heat conduction, energy consumption resulting from the decomposition, and the energy transfer associated with vaporous migration. For a given thermal and mechanical damage of a sandwich composite system, a multi-scale solution framework was formulated to determine the material response and failure at the structural level from the damage progression at its constituent, ply, and laminated plate level. The delamination failure along an interface was characterized by a cohesive element approach with a user-defined cohesive law while the diffuse damage resulting from the fiber/tow/matrix failure in the sandwich composite was characterized using a continuum damage model. A loaded sandwich beam with and without a fire was considered to demonstrate the effects of fire damage on the ultimate strength of the sandwich structure.     

钢筋混凝土T形截面梁温度场精确算法

研究标准升温曲线作用下混凝土T形截面梁温度场的变化,对混凝土T形截面梁进行60 min和75 min火灾试验;介绍三维、二维导热微分方程,采用有限元和有限差分的混合方法计算截面温度场,计算中考虑了混凝土、钢筋的热工性能和混凝土的水分蒸发对温度场的影响,计算结果与试验结果吻合较好。实验和计算结果表明,T形梁翼缘内的温度分布与单面受火板相似,腹板内的温度分布与三面受火矩形截面梁相似;T形截面内,腹板角部温度最高,翼缘下部腹板由侧面向核心区温度下降最快。     

A simple method for combining fire and structural models and its application to fire safety evaluation

To consider the actual fire characteristics in the fire response analysis of building structures and to simplify the complex relationship between the fire analysis model and the structural finite element analysis model, a spatio-temporal model of the fire temperature and heat flux boundary for heat conduction analysis is developed. The proposed model adopts a two-way orthogonal polynomial approach for fitting the discrete data from the fire simulation and obtains continuous spatial polynomial equations. It is shown to be accurate for capturing the distributions of temperature and heat flux that are required for a heat conduction analysis and a thermal mechanical coupling analysis. Finally, the model is implemented through user-subroutines UTEMP and DFLUX in ABAQUS, and it is applied to a new archive in Beijing. The results show that this method may be used to combine fire simulation and structural analysis for the safety evaluation of structures under fire.     

火灾下圆钢管混凝土柱的有限元计算

钢管混凝土组合柱在实际工程应用中有其优良的工作和施工性能。火灾发生时,由于核心混凝土的吸热作用,延缓了钢管的升温,很大程度上提高了钢管混凝土柱的耐火极限。在已有模型的基础上,对圆形截面核心混凝土高温下的材料模型进行了修正,基于ABAQUS大型有限元平台建立了圆形截面钢管混凝土柱的有限元模型,并利用其模型进行了耐火极限的计算,有限元计算结果与国内外相关的试验数据进行了对比,验证了有限元模型的正确性,并对其火灾下轴向变形-受火时间的全过程进行了分析。可在此基础上进一步开展钢管混凝土抗火相关的研究工作。     

Experimental study on the influence of different thermal insulation materials on the fire dynamics in a reduced-scale enclosure

Four scaled (1:5) fire experiments with two identically classified types of commercially available sandwich panels incorporating either stone wool (SW) or polyisocyanurate (PIR) foam as cores were conducted using a modified version of the ISO 13784-1 (Reaction to fire tests for sandwich panel building systems — Part 1: Small room test) standard. This was to assess the suitability of scaled experiments for assessing sandwich panel fire behavior. In the modified version of the test standard (scaled and full experiments), the fire severity was increased to simulate fires that could occur in commercial premises. This was achieved by prolonging and doubling the heat release rate output of the gas burner at the end of the experiments. Furthermore, non-structural damages such as screw-hole damages were applied to the enclosures to reflect real life observations.The results showed differences in the fire behavior, depending on whether the enclosures were constructed of panels filled with SW or PIR insulation material. The mass losses of the insulation materials showed significant contribution from the PIR cores, regardless of fire load and the non-structural damage.The qualitative behavior with respect to the “flashover” failure criterion, as stated in the ISO 13784-1, was successfully obtained in all of the scaled experiments. As such, the scaled experiments mimicked the behavior of the full scale SW experiments to a satisfactory degree. However, the PIR compartments failed considerably earlier in the full scale tests than in the scaled experiments. Therefore, it can be concluded that when the energy contribution from the core material remained negligible compared to the gas burner, the measured parameters matched quite well. Therefore, if the insulating core material does not dominate the fire dynamics of the compartment and the energy from the gas burner dictates the fire scenario then the scaled set-up will predict the temperature in the full scale compartment. Based on this and with further development with respect to, especially, time, this kind of scaled experiments could be a valuable testing method for assessment of the behavior of sandwich panel, and therefore merit further studies and eventually increased use.     

建筑用绝热金属面夹芯板受火时隔热性能研究

通过对夹芯板受火时隔热性能进行有限元分析研究,得到不同厚度岩棉夹芯板和聚苯乙烯泡沫EPS及聚氨酯TPU夹芯板的耐火极限,并与试验值进行对比;最后,针对通常不符合防火下隔热要求的夹芯板提出改进措施,以满足规范要求.     

中空夹层方钢管再生混凝土柱火灾后剩余承载力

为研究中空夹层方钢管再生混凝土柱火灾后剩余力学性能,运用有限元分析软件ABAQUS建立了ISO 834标准火灾作用后中空夹层方钢管再生混凝土柱的有限元模型,分析了截面温度场和应力场的变化规律。在此基础上分析了混凝土强度、钢材强度、计算长度、受火时间、空心率、混凝土取代率、偏心率等参数对构件火灾后剩余力学性能的影响;结合大量计算结果给出了中空夹层方钢管再生混凝土柱火灾后剩余承载力简化计算公式。结果表明:构件的火灾后剩余承载力随钢材强度和混凝土强度的增加而增加;构件火灾后剩余承载力随计算长度和受火时间的增加,总体呈降低趋势,当受火时间超过60 min时,构件火灾后剩余承载力急剧降低;空心率和混凝土取代率对构件火灾后剩余承载力影响较小,构件火灾后剩余承载力随空心率的增加而降低,随混凝土取代率的增加先增加后降低;构件火灾后剩余承载力随偏心率的增加而降低;所提公式计算精度良好,可为中空夹层方钢管再生混凝土柱抗火设计提供参考。     

预应力钢结构锚固节点瞬态温度场分析

根据试验数据,建议了热铸锚填料锌铜合金和冷铸锚填料环氧树脂/钢丸混合物的比热容及导热系数计算公式.基于热传导理论和ABAQUS数值传热模拟平台,进行了ISO834标准火灾下锚固节点截面瞬态温度分布的参数分析.结果表明:随着受火时间的延长,热铸锚杯壁截面温度分布非均匀性逐渐显现,锌铜合金填料的升温速率显著低于锚杯壁;冷铸锚杯壁截面温度分布较均匀,包裹钢丝的填料区域较填料其他区域温度分布非均匀性降低.总体上,锚头沿中心轴的温度分布非均匀性显著,且升温明显滞后于环境温度,无防火保护的情况下锚杯内壁界面处的填料将在较短时间内失效.所提出的热铸锚截面瞬态升温理论计算式,为预应力钢结构锚头抗火承载力验算提供了理论依据.