膨胀型防火涂料

在英格兰和威尔士《建筑规范(BuildingRegulation)》的许可文件B中,是这样描述防火安全的,“建筑物的设计和建造必须保证,在发生火灾时,建筑物能保持相当长时间的稳定性。”那么“相当长时间”是多长时间呢?在该文件中,依据建筑物不同的高度和用途,规定了不同的耐火时间,从30 m     

膨胀型过氯乙烯防火涂料

本文介绍了以过氯乙烯为成膜物质,添加成炭剂、脱水催化剂、发泡剂制备膨胀型防火涂料的组成、工艺、性能和防火效果。采用正交试验法讨论了主要组成成分对涂料的防火性能的影响。     

非膨胀型防火涂料等效热传导系数研究

基于防火涂料标准耐火试验方法,对涂覆非膨胀型防火涂料的钢板试件和工字型钢试件进行了耐火试验,用所得的试件升温曲线计算非膨胀型防火涂料的热传导系数随涂层温度变化曲线.提出将涂层温度为400~800℃时的热传导系数平均值作为涂层等效热传导系数,并用以进行被保护钢构件火灾下升温计算,所得钢构件的升温曲线与试验测得的升温曲线符合良好.参数分析表明,等效热传导系数与试件截面形状系数无关,与涂层厚度相关,表明用小尺寸钢板试件耐火试验结果计算所得的等效热传导系数可用于预测其他被保护钢构件在火灾下的升温.对不同涂层厚度热传导系数进行线性拟合,提出以涂层厚度20mm时的等效热传导系数作为非膨胀型防火涂料等效热传导系数特征值.     

非膨胀型无机防火涂料的热解分析

对SWH室外厚型钢结构防火涂料在高温试验的基础上进行了热重分析。在升温速率为25℃／min下热解,得到防火涂料的热重曲线（TG）、微商热重曲线（DTG）和差热曲线（DTA）。发现样品的失重过程由干燥和初挥发段,升温段,热解段,剩余物质加热段4个阶段组成,并对所得曲线进行了详细分析。结果表明：在200～400（期间,SWH室外厚型钢结构防火涂料的阻热性能减弱。     

膨胀型防火涂料

介绍了ＪＹ－ＦＨＺ膨胀型防火涂料阻燃体系的确定,催化剂、发泡剂、成炭剂、成膜物及颜填料等助剂的选用,以及生产配方、生产工艺的设计和施工注意事项等。     

膨胀型防火涂料防火组分热分析

本文利用DSC25型差示扫描量热仪对膨胀型防火涂料中阻燃剂各主要成分的热性能进行分析,研究它们的热分解过程及其相互作用的情况,探讨其阻燃机理,以便为阻燃剂配方的合理选择提供依据.     

水性膨胀型电缆防火涂料

本文主要在提高水性防火涂料柔韧性的方面做了一些工作，并得到了一种各方面性能都较好的防火涂料。     

防火涂料的发展和膨胀型防火涂料阻燃机理的探讨

本文概述了防火涂料的发展,介绍了膨胀型防火涂料的组成,并采用先进的仪器和分析方法如差热分析法（DTA）,热重量分析法（TG）、电子扫描电子显微镜（SEM）、X射线衍射（XRD）、傅里叶变换红外光谱（FTIR）对膨胀型防火涂料的阻燃机理进行了探讨。     

用有限元法解算室内火灾下钢构件截面温度场

介绍了一种用有限元法确定在室内局部火灾条件下钢构件截面温度场的方法 ,以一个具体火灾房间为例 ,介绍了有限元的建模、分网、加载及求解的技巧     

温度场和温度应力的有限元分析

阐述了平面温度场与温度应力进行有限元分析的全过程,结合ANSYS大型软件对温度场与温度应力进行了模拟计算,为实际工程中考虑温度场与温度应力的作用提供了依据。     

Effects of partial fire protection on temperature developments in steel joints protected by intumescent coating

This paper presents experimental results of temperature distribution in fire in four typical types of steel–concrete composite joint (web cleat, fin plate, flush endplate and flexible endplate) with different fire-protection schemes. The test specimens were unloaded and the steelwork of each joint assembly was exposed to a standard fire condition [ISO 834, 1975: Fire Resistance Tests, Elements of Building Construction, International Organization for Standardization, Geneva] in a furnace. In total, 14 tests were conducted, including 4 tests without any fire protection and 10 tests with different schemes of fire protection. The main objective of these tests was to investigate the effects of three practical fire-protection schemes as alternatives to full fire protection of the entire joint assembly. The three alternative methods of fire protection were: (1) protecting a segment, instead of the entire length, of the beams; (2) unprotected bolts and (3) protecting the columns only. The main results of these tests are: (1) if all the steel work (excluding the bolts) in the joint assembly was protected, whether or not protecting the bolts had very little effect on temperatures in the protected steelwork other than the bolts. The bolt temperatures were higher if they were not protected than if they were protected, but the unprotected bolt temperatures in a joint with fire protection to other steelwork were much lower than bolt temperatures in a totally unprotected joint; (2) as far as joint temperatures are concerned, protecting a segment of 400 mm of the beam was sufficient to achieve full protection and (3) if only the column was protected, only the joint components that were in the immediate vicinity of the column (such as welds) developed noticeably lower temperatures than if the joint assembly was unprotected, but due to heat conduction from the unprotected steel beams, these temperature values were much higher than if the joint assembly was protected. Furthermore, the column temperatures in the joint region were much higher than the protected column temperatures.     

防火涂料破损对钢构件温度分布的影响

采用有限元数值分析得出了防火涂料局部破损后钢构件的温度分布规律,提出了临界破损长度的概念。分析了柱长、防火涂料厚度、截面形状系数,以及标准火灾升温时间对防火涂料局部破损后钢构件温度分布的影响。给出了破损长度和其影响区域内温度分布的计算公式,可供结构抗火性能分析和设计参考。     

非标准火灾下结构温度场分析方法

提出一种基于FDS 火灾模型与COMSOL 结构力学模型的温度场转换方法,并通过MATLAB 编写相应软件实现该方法,进而对建筑构件进行热传递分析。以矩形混凝土薄板为例,采用该方法对其进行数值模拟,计算结果显示,FDS 模型与COMSOL 模型中温度场变化一致,通过对比两个模型的测点温度,结果显示误差最大为6.8%。该方法可以用于研究实际火灾中温度对建筑结构的力学性能的影响,为提高建筑韧性提供了一种热力耦合方法。     

Load-temperature-deformation behaviour of partially protected steel columns in fires

In recent years many tests have been carried out to assess the fire resistance of steel members at elevated temperatures. These tests are very expensive to undertake and the results obtained for similar tests carried out in different furnaces can vary quite considerably. Analytical methods have been developed for determining the fire resistance of steel members but these are often only concerned with predicting the collapse condition and may not allow the behaviour of the member to be fully analysed as the temperature increases. A finite element program (ELTEMP) has been developed by the authors to assess the behaviour of steel columns at elevated temperatures. The effects of temperature gradients over the cross-section, such as occurs, for instance, in the case of members built into fire-resistant masonry walls, are included. The validity of the program has been checked by comparing results obtained from ELTEMP with those from actual fire resistance tests for both uniform and nonuniform temperature distributions. The comparisons show that ELTEMP generally gives good correlation with test results. Two small-scale model tests undertaken for this purpose are described.     

热反射隔热涂料对混凝土温度场的影响规律研究

日光辐射下结构内部产生的温度荷载是混凝土桥梁及轨道等结构的主要荷载,通过特殊措施改变结构温度场可降低结构荷载,从而降低结构的造价或减小结构的不利温度应力(及变形)。探讨了混凝土表面涂刷反射隔热涂料对混凝土温度场的影响规律,通过模拟日光照射,测试了反射隔热涂料对不同强度等级的混凝土试件表面温度、芯部温度、温升(降)速率及温度梯度的影响规律。结果表明,白色反射隔热涂料可有效地降低混凝土的表面温度、芯部温度、温升(降)速率,并可显著降低混凝土的温度梯度。研究结果为主动降低特殊混凝土结构温度荷载提供了一种新思路。     

大体积粉煤灰混凝土水闸墙温度场分析

从某大体积粉煤灰混凝土水闸墙现场监测温度出发，分析了大体积粉煤灰混凝土温度场的计算原理，利用有限元软件对该水闸墙的温度场进行了有限元数值模拟分析，并将有限元分析结果与现场实测结果进行了比较。     

平板对接焊的温度场和应力场有限元分析

针对中厚板在焊接过程中存在残余应力和变形,运用ANSYS热-结构的耦合分析功能,对焊接温度场和应力场进行了模拟计算。结果表明,焊缝区及附近存在较大的焊接残余拉应力,应力最大值接近或超过材料的屈服强度,离开焊缝区后焊接残余应力迅速衰减为压应力。     

某拱形结构混凝土浇筑温度场仿真分析

根据瞬态热传导方程,用有限元分析软件对拱形结构混凝土动态浇筑过程进行模拟和对温度场进行仿真分析。结果表明,采用有限元仿真分析混凝土浇筑温度场是可行的;混凝土内部最大温升在浇筑30.84h时达到峰值,约为62℃;混凝土内部最大温度梯度发生在浇筑22.42h时,为46.4℃/m;混凝土内部最大温度应力发生在浇筑35.84h时,最大温度第一主应力为0.070MPa。根据温度梯度随时间的变化规律,对现场混凝土适时采取保温隔热措施,防止了拱形结构混凝土温度裂缝的产生。