摘要
用红外热像无损检测技术对飞机铝合金板背面的腐蚀进行无损评估,分析试验系统的腐蚀探测能力,检验理论分析和一些数据处理方法的有效性。检测对象包括参考试件和存在自然腐蚀的真实飞机结构件。在检测参考试件上的以机制平底孔加化学腐蚀处理而制作的替代腐蚀缺陷时,时间域傅里叶变换法可获得最高的信噪比(SNR),在1.8mm铝板上直径大于10mm的各个缺陷区,腐蚀探测极限的估计值约为10%。对带有自然腐蚀的飞机铝合金件的检测表明,原始热像或简单处理算法,如时间平均,就能提供很高的SNR值。而一些先进处理算法,如脉冲相位法(PPT)、主分量分析(PCA)、多项式拟合和相关分析,在检测飞机铝板的自然腐蚀时其有效性值得怀疑。用三维传热数值计算对飞机铝试件的热无损检测进行了理论分析,所得到的理论温度分布及其变化过程与实测值相近。对一维腐蚀表征方法在航空铝板检测中的有效性进行了检验,证明该方法是有效的。
Rear-surface corrosion on aviation aluminum panels is evaluated by infrared thermal nondestructive testing （TNDT）. The Corrosion detection capability of the experiment setup is analyzed. The validity of theoretical analysis and some available data processing algorithms are verified. In the inspection of a reference sample with fiat-bottomed hole surrogates of corrosion, the highest signal-to-noise ratio （SNR） is ensured by Fourier transformation in time domain; the corrosion detection limit has been estimated as about 10% in defect areas with diameter larger than 10 mm on 1.8 mm-thick aluminum panels. The inspection of a naturally-corroded aircraft panel shows that high SNR values can be provided by original thermal images or simple processing algorithms, such as averaging, however the validity of some advanced algorithms, such as pulsed phase thermography （PPT）, principle component analysis （PCA）, polynomial fitting and correlation analysis, is doubtful in detecting naturally-corroded aircraft panels. The thermal NDT of the aircraft aluminum sample is analyzed by numerical solution to the corresponding 3D heat conduction problem, the theoretical temperature distribution and evolution are similar to the measured values. A well known 1D corrosion characterization approach is verified on aviation aluminum plates, and is proven to be valid.
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2009年第3期208-214,共7页
Journal of Mechanical Engineering
基金
国家自然科学基金(60672101)
航空科学基金(2006ZD51030)
北京市教育委员会共建资助项目
关键词
铝合金
腐蚀
热无损检测
红外热像
估计
Aluminum Corrosion Thermal nondestructive testing Infrared thermography Evaluation
