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    陈勇平, 高甜, 李德山, 郭文静. 马尾松木材空洞开裂残损的雷达检测成像初探[J]. 北京林业大学学报, 2017, 39(3): 112-118. DOI: 10.13332/j.1000-1522.20160313
    引用本文: 陈勇平, 高甜, 李德山, 郭文静. 马尾松木材空洞开裂残损的雷达检测成像初探[J]. 北京林业大学学报, 2017, 39(3): 112-118. DOI: 10.13332/j.1000-1522.20160313
    CHEN Yong-ping, GAO Tian, LI De-shan, GUO Wen-jing. Preliminary study on radar detection and imaging of cavities and cracks of Pinus massoniana[J]. Journal of Beijing Forestry University, 2017, 39(3): 112-118. DOI: 10.13332/j.1000-1522.20160313
    Citation: CHEN Yong-ping, GAO Tian, LI De-shan, GUO Wen-jing. Preliminary study on radar detection and imaging of cavities and cracks of Pinus massoniana[J]. Journal of Beijing Forestry University, 2017, 39(3): 112-118. DOI: 10.13332/j.1000-1522.20160313

    马尾松木材空洞开裂残损的雷达检测成像初探

    Preliminary study on radar detection and imaging of cavities and cracks of Pinus massoniana

    • 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: Masson pine (Pinus massoniana), which is a commonly used wood species in ancient timber buildings was studied in this paper, and cavities in the centre and cracks at the edge were artificially made at the end of the wood columns to simulate the common damages in ancient timbers. Radar non-destructive testing technology was adopted to detect the man-made damages, and the influencing factors for radar imaging were studied. By analysis of the specific patterns of the radar waves, rapid identification and characterization of the cavity and crack damages of the wood columns can be realized. The results indicated that the radar non-destructive testing technology can be used to detect the internal cavities and external cracks of wood columns rapidly, although there is a discrepancy between the detected damage area by the radar and the actual damage area. When the cavities inside the column were detected by the radar wave, strong black-white-black patterns will appear at the interface of the radar image and the corresponding reflection waveform is valley-peak-valley. By contrast, when the external damages such as cracks on the surface were detected, longitudinal interference stripes differing from the normal background will appear on the radar image. The detection of internal cavities is not severely affected by the presence of the external cracks, and also the closely attached bark or base coat on the surface will not pose a significant negative influence on the identification of the internal damages. The moisture content of timber was found to have an impact on the radar detection results. With other conditions fixed, the higher the moisture content of the timber is, the smaller the damage area detected by the radar technology is. The estimated boundary of the cavity damages may be offset slightly under the influence of other factors such as the moisture content; therefore, in actual testing, extended analysis in depth direction should be preformed based on the radar image. All of the results illustrated that the radar non-destructive testing technology can be used to detect the cavity and crack damages of timber rapidly, but the quantitative characterization of the damages needs to be further studied.

       

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