火灾下木构件温度场分布数值模拟研究  

Numerical Simulation of Temperature Distribution of Timber Members in Fire

作　　者：陈玲珠 

机构地区：[1]上海市建筑科学研究院上海市工程结构安全重点实验室,上海200032

出　　处：《结构工程师》2016年第1期31-37,共7页Structural Engineers

基　　金：上海市优秀技术带头人计划(15XD1522600);国家自然科学基金资助项目(51178115)

摘　　要：木材是可燃性材料,研究木构件的抗火性能具有重要意义。受火后木材表面发生炭化,由于炭化层的导热系数较低,木材表面的炭化层能减缓热量传递并延缓木材燃烧,因此木材受火后传热是一个非常复杂的问题。采用ABAQUS较系统地研究了木构件的截面温度场分布规律,为木构件抗火性能研究提供基础。模型中木构件采用二维平面单元模拟,材料的热工特性参数根据欧洲规范(EN 1995-1-2)取值。分别采用三面受火木梁和四面受火木柱试验结果对数值模型的可靠性进行验证,并进一步研究了木材干密度和含水率对木构件温度场分布的影响。研究表明,材料密度越大,截面相同位置处的温度越低,截面温度上升越慢;而含水率对截面温度分布影响较小。Wood is combustible material and study on the fire performance of timber members is meaningful. When exposed to fire, a charring layer develops on the surface of timber members. It protects the interior of the timber cross-section from heat. Because the thermal conductivity of the charring layer is much lower than that of the unburnt wood, it can reduce the amount of heat transferred by the surface burning to the unburnt part of the wood section. However, the heat transfer of the wood is a complicated problem. The temperature distribution of timber members was systematically analysed using the software package, ABAQUS, in this paper, providing basis for the study of the performance of timber members in fire. The two-dimensional plane element was used to model the timber members. The thermal properties of the components in the model were from Eurocode EN 1995-1-2. The model was validated by comparing numerical results of temperature field with available experimental results of three-side fire exposed timber beams and four-side fire exposed timber columns. The influence of dry density and moisture content on the temperature distribution of timber members was further studied. It was found that the temperature at the same place of the cross-section was lower and the temperature increased more slowly for timber members with larger dry density. It was also found that the moisture content had negligible influence on the temperature distribution.

关 键 词：火灾 木构件 温度分布 数值模拟 

分 类 号：TU366.2[建筑科学—结构工程]