马尾松木材空洞开裂残损的雷达检测成像初探

发布时间：2018-10-11 20:07

【摘要】：本研究以木结构古建筑常用的马尾松木材为研究对象,采取人工模拟的方法在马尾松木段端部制作中心空洞及外缘开裂的残损,通过开展残损木材的雷达探测及成像影响因素研究,给出不同残损在雷达检测下的表现形态,实现木材内部空洞和外缘开裂残损的快速识别及表征。研究结果表明:利用雷达无损检测技术可以实现木材内部空洞和外缘开裂残损的快速检出,而对残损大小的评估,雷达检测面积与实际残损面积存在偏差;当雷达探测到木材内部空洞时,其交界面会出现强烈的黑-白-黑形态图像,对应的反射波形为谷-峰-谷;当雷达探测到木材外缘开裂等凹陷特征时,其图像上会出现不同于正常背景的纵向干扰条纹;木材外缘开裂并不严重影响内部空洞残损的检出,木材表面存在贴合紧密的树皮或保护性地仗对内部残损的识别也无明显影响;木材含水率对雷达检测结果影响较为显著,在其他条件一定时,木材含水率越高,其雷达检测残损面积越小;雷达检测结果受含水率等因素影响,其残损的检测边界可能会产生一定的偏移,因此,在实际检测中应根据雷达检测图像进行深度方向的延伸分析。通过本研究可知:雷达无损检测技术可以实现木材空洞和开裂残损的快速检出,但对于残损的定量评估有待于进一步研究。
[Abstract]:In this study, the wood of Pinus massoniana (Pinus massoniana), which is commonly used in ancient wooden structures, was used to make central cavities and dehiscence at the end of Pinus massoniana segment by artificial simulation. Through the research of radar detection and imaging factors of damaged wood, the appearance of different damaged wood under radar detection is given, and the quick identification and characterization of interior cavity and outer edge crack and damage of wood are realized. The results show that the rapid detection of interior cavity and outer crack and damage can be realized by using radar nondestructive testing technology. However, there is a deviation between the radar detection area and the actual damage area in the evaluation of the damage size. When the interior cavity of wood is detected by radar, a strong black-white-black shape image will appear at the interface, corresponding reflection waveform is valley-peak-valley, and when radar detects the depressions of wood outer edge, The longitudinal interference stripes will appear on the images, and the cracks on the outer edge of the wood do not seriously affect the detection of the internal cavity damage. There is no obvious effect on the identification of internal damage by the existence of closely bonded bark or protective bark on the wood surface, and the moisture content of wood has a significant effect on the results of radar detection, and the higher the moisture content of wood is, the higher the wood moisture content is when other conditions are fixed. The smaller the area of radar detection is, the smaller the detection result is, and the more the moisture content is, the more the detection boundary may be. Therefore, the depth extension analysis of radar detection image should be carried out according to the actual detection. Through this study, we can know that radar nondestructive detection technology can be used to detect the wood cavity and crack damage quickly, but the quantitative evaluation of the damage needs further study.
【作者单位】：中国林业科学研究院木材工业研究所;故宫博物院;
【基金】：国家自然科学基金项目(31570711) 故宫博物院科研课题(KT2015-06)
【分类号】：S781.5;TN957.52

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