| 任青文,沈雷,孙立国,严洋,顾嘉丰.开裂混凝土有效导热系数的细观数值研究[J].水利学报,2015,46(8):892-899 |
| 开裂混凝土有效导热系数的细观数值研究 |
| Numerical study of the influence of cracks on effective thermal conductivity of concrete in meso-scale |
| 投稿时间：2014-12-19 |
| DOI：10.13243/j.cnki.slxb.20141525 |
| 中文关键词: 混凝土 有效导热系数 细观尺度 裂纹 有限单元法 |
| 英文关键词: concrete effective thermal conductivity crack meso-scale finite element method |
| 基金项目:国家自然科学基金资助项目（11132003） |
|
| 摘要点击次数: 3122 |
| 全文下载次数: 40 |
| 中文摘要: |
| 通过建立一种细观数值模拟方法,研究了混凝土力学行为对其导热性能的影响,揭示了有效导热系数在拉伸破坏过程中的变化规律。研究发现,混凝土开裂明显阻碍热流通过,导致其有效导热系数显著下降,而且,有效导热系数变得各向异性,造成热流方向改变。因此在热-力耦合计算中不能忽略裂纹对温度场的影响。继而研究了骨料体积含量对开裂混凝土导热系数的影响,结果表明无论是开裂前还是开裂后,骨料体积含量越高,其导热性能越好,有效导热系数下降率越大。通过与已有试验成果比较,验证了本文细观数值模型的正确性,所给出的预测开裂前后混凝土导热系数的方法,可用于热-力耦合分析。 |
| 英文摘要: |
| A mesoscopic numerical method is presented to quantify the cooperation of concrete's mechanics and thermal behavior, and the method is used to discover the evolution of effective thermal conductivity (ETC) during uniaxial tensile failure. The results show that the decrease of ETC is significant causing the drop of heat flux,while micro-cracks are initializing and propagating. Furthermore,the ETC becomes anisotropic, which influences the direction of heat flow. This effect of cracks should be considered in thermal-mechanical coupling simulation, while former works have ignored. Also, simulations on several speci-mens with different aggregate volume fraction(AVF) indicate that AVF has a positive effect on concrete's ETC regardless crack existence. The reduction rate of ETC increases with the rise of AVF. In accordance with the mesoscopic numerical results, a semi-theoretical model based on Maxwell model is suggested for the estimation of cracked concrete ETC. The computation of numerical method and semi-theoretical model are in good agreement with the existing experimental results and can be applied for thermal-mechanical cou-pled analysis. |
|
查看全文
查看/发表评论 下载PDF阅读器 |
| 关闭 |
|
|
|