Study on Standardization of Thermography for Separation Detection of Finish Material on External Wall of Building

本研究定量阐明了热成像技术在建筑外墙面砖、砂浆等饰面材料分离检测中的适用性。本会计年度的研究成果总结如下：1)利用实物试件进行实验讨论；通过使用带有人工缺陷的试样，阐明了这种检测方法在实验室水平上的局限性。本实验的参数为：人工缺陷的面积、深度和厚度；季节、日照、测量时间；试件内外表面风速和热差。特别为了提高实验的再现性，本实验采用了太阳-空气温度的热控制，并在计算温度中加入日照热流密度。2)数据分析程序的开发；将数据分析程序应用于建筑外墙饰面材料分离检测，需要解决许多问题。在本财政年度，在数据分析中规划了以下几点考虑：几何校正；热梯度校正；污迹和风速校正。3)非定常热传导有限元分析；延续上一财年，采用三维有限元法对含各种缺陷的想象外墙模型进行非定常热传导分析。参数为缺陷的面积、深度和厚度；墙体内外表面热差；以及加热和冷却的效果。将分析结果与实验结果进行了比较，明确了该方法在理想状态下的局限性和最佳条件。

In this study, applicability of thermography for separation detection of finish material, such as tile and mortar, on external wall of building are clarified quantitatively.The results in this fiscal year are summarized as follows :1) Experimental discussion using the real size specimen ; The limitation of this detection method on laboratory level is clarified by using specimens with artificial defects. The parameters in this experiment are as follows : area, depth and thickness of artificial defects ; season, insolation and measuring time ; wind velocity and thermal difference between inner and outer surface of specimen. Especially, in order to improve the reproducibility, this experiment was carried out using thermal control with sol-air temperature, that is added to calculated temperature equal to heat flux by insolation.2) Development of program for data analysis ; Many problems should be resolved in order to apply the program for data analysis to separation detection of finish material on external wall of building. In this fiscal year, a few considerations were programd in the data analysis as follows : geometrical correction ; thermal gradient correction ; stain and wind velocity correction.3) Unsteady heat conduction analysis by FEM ; Being continued from the last fiscal year, unsteady heat conduction analysis on imagined external wall model with various defects was carried out by using three dimensional finite element method. Parameters are area, depth and thickness of defect ; thermal difference between inner and outer surface of wall ; and effect of heating and cooling. The analytical results are compared with experimental results, and the limitation and the best condition for this method under ideal status is clarified.