改进的HHT在复合材料盒段损伤检测中的应用

DAMAGE DETECTION OF COMPOSITE WINGBOX STRUCTURES USING IMPROVED HILBERT-HUANG TRANSFORM

提出一种基于结构振动和改进希尔波特黄变换的结构损伤检测方法,利用改进的希尔波特黄变换技术,研究悬臂机翼盒段结构的损伤检测问题。改进的希尔波特黄变换由三部分组成,小波分析、希尔波特黄变换及一种简单但有效的经验模式函数选择方法。用改进的希尔波特黄变换处理完好盒段结构与损伤盒段结构在方波信号激励下的动力响应信号,从中提取出结构损伤信息指标——瞬时能量变化量作为损伤特征参数。结果表明,所构造的结构损伤特征量对表征复杂结构小损伤具有较好的灵敏度。

A vibration-based approach to detect damage in a cantilever composite wingbox is studied using the improved Hilbert- Huang transform （HHT）. The improved HHT is composed of HHT with wavelet packet transform （WPT） and a simple but effective method for intrinsic mode function （IMF） selection. In order to obtain structural dynamic responses, which imply plentiful damage informarion, the composite wing boxes were excited by a contrived square wave signal. Then, the dynamic responses of intact wingbox and damaged wingbox are disposed using improved HHT. Hilbert spectrums of dynamic response signals are obtained. Finally, a feature index vector of structural damage, i.e. the variety quantity of instantaneous energy △E1 , is extracted. The obtained results show that the proposed damage feature index vector is sensitive to composite structural damage.