基于红外热成像的古建筑墙内暗柱材料缺失检测  

Material deficiency test of fully-concealed wood column in walls of ancient buildings based on infrared thermal imaging

作　　者：王皓宇 彭林 张厚江[1,2] 雷智勋 王辉 张典[3] 唐家英 管成[1,2] Wang Haoyu;Peng Lin;Zhang Houjiang;Lei Zhixun;Wang Hui;Zhang Dian;Tang Jiaying;Guan Cheng(School of Technology,Beijing Forestry University,Beijing 100083,China;Joint International Research Institute of Wood Nondestructive Testing and Evaluation,Beijing Forestry University,Beijing 100083,China;The Palace Museum,Beijing 100001,China)

机构地区：[1]北京林业大学工学院,北京100083 [2]北京林业大学木材无损检测国际联合研究所,北京100083 [3]故宫博物院,北京100001

出　　处：《北京林业大学学报》2024年第3期132-144,共13页Journal of Beijing Forestry University

基　　金：故宫博物院科研项目(201909012)。

摘　　要：【目的】墙内暗柱是木结构古建筑的重要承重构件之一,因其处于潮湿和缺乏通风的环境,故多存在腐朽及由严重腐朽导致的材料缺失等缺陷,容易失去原有的承载能力和稳定性。墙内暗柱自身构造导致现有的检测手段受限,易造成不可逆的损坏。故本研究基于红外热成像原理开展墙内暗柱材料缺失缺陷检测理论与试验研究,以期为基于红外热成像的墙内暗柱缺陷状况无损检查方法的建立奠定部分前期基础。【方法】首先,从理论角度探讨古建筑墙内暗柱传热过程,推导稳态下木柱区域与纯墙体区域的温度公式,分析影响木柱材料缺失缺陷区域温度变化的因素;然后,建立试验模型,进行墙内暗柱缺陷红外检查试验,采集红外图像;最后,通过分析所获得的红外热图,探讨墙内暗柱材料缺失缺陷大小与墙体表面温度分布之间的关系。【结果】(1)理论研究表明:由于木材的横向导热系数远小于墙体导热系数,加热面加热温度相同的情况下,木柱墙体外表面所对应的温度偏低;墙内暗柱的检测效果主要受到缺陷尺寸,即缺陷高度、缺陷深度的影响。(2)试验结果表明:在稳态热传导下,木柱处的墙体外表面温度要低于纯墙体,即木柱处红外图像的颜色更浅;木柱缺陷的存在会使缺陷处墙体表面温度变高,红外图像颜色变深;木柱缺陷高度越大,缺陷导致的高温范围越大;木柱缺陷深度越大,缺陷区域温度值越高。(3)在非稳态热传导下,木柱中线温差分别与木柱缺陷高度(R^(2)≥0.964)、深度(R^(2)≥0.951)呈极强的正相关。(4)在木柱缺陷较小的情况下,墙体表面温度不因缺陷的存在而发生明显改变。【结论】木柱的缺陷高度与深度是影响缺陷红外热成像检测效果的主要因素,红外热成像法应用于古建筑墙内暗柱材料缺失缺陷的筛查与评估是可行的。[Objective]Fully-concealed wood column is one of the important load-bearing components of ancient wood buildings.Due to its humidity and lack of ventilation,it often has defects such as decay and material deficiency caused by serious decay,and it is easy to lose the original carrying capacity and stability.The structure of fully-concealed wood column in walls makes the existing detection methods limited and easy to cause irreversible damage.Therefore,based on the principle of infrared thermal imaging,this study carried out theoretical and experimental research on the detection of material deficiency of fully-concealed wood column in walls,in order to lay a part of the preliminary foundation for the final establishment of the non-destructive inspection method of fully-concealed wood column defects in walls based on infrared thermal imaging.[Method]Firstly,the heat transfer process of fully-concealed wood column in walls of ancient buildings was discussed from the theoretical point of view,and the temperature formula of the wood column area and the pure wall area under steady state was deduced,and the factors affecting the temperature change in the material deficiency defect area of the wood column were analyzed.Then,the test model was established,and the infrared inspection test of fully-concealed wood column in walls was carried out to collect the infrared image.Finally,by analyzing the infrared heat map,we discussed the relationship between the material deficiency defect size of fully-concealed wood column in walls and the temperature distribution of the wall surface.[Result](1)The theoretical research showed that the transverse thermal conductivity of wood was much smaller than that of the wall,and the temperature corresponding to the outer surface of the wood column wall was lower given the same heating temperature on the surface.The detection effect of the fully-concealed wood columns in the detection wall was mainly affected by the defect size,i.e.,the defect height and the defect depth.(2)The test results s

关 键 词：古建筑 墙内暗柱 缺陷 红外热成像 无损检测 

分 类 号：TU366.2[建筑科学—结构工程] TN29[电子电信—物理电子学]