A split spectrum processing ( SSP) algorithm was proposed to estimate the time of flight (ToF) of the damage-scattered fundamental symmetrical (S0) mode by comparing the instantaneous amplitude variation degree (IPVD) of a captured wave signal and that of a benchmark signal in a damage case, so as to realize the ultrasonic guided wave-based damage identification. Wave signals captured from an intact aluminum plate were firstly acquired in ideal environment (without noise) as a benchmark one. Then, a notch was artificially introduced into an aluminum plate and the wave signals captured from the notched aluminum plate ( damage case) were acquired in different environments ( without and with noise) . Test results demonstrated that even though the captured wave signal from the damage case has a lower signal-to-noise ratio (SNR) , the IAVD of the captured wave signal extracted with SSP algorithm is almost not influenced by noise. As result, the proposed SSP algorithm was capable of estimating the ToF of the damage-scattered So mode with higher precision, regardless of very strong noise disturbance, so as to identify successfully the notch in an aluminum plate further combining with the triangulation algorithm.%利用分谱处理(SSP)算法,通过比较基准波信号和检测波信号的瞬时幅值变化度(IAVD)来评估损伤散射的基础阶对称(S0)模式的飞行时间(ToF),最终实现基于超声导波的损伤识别.首先在理想的工作环境中(无噪声),对无缺陷的铝板进行检测,并把所采集的波信号作为基准信号.然后在不同的工作环境中(无噪声和有噪声)检测带有切缝缺陷的铝板,并把所采集的波信号作为检测信号.实验结果表明,当检测波信号的信噪比较低时,噪声能量严重干扰了检测波信号的能量分布.然而,SSP算法所提取的检测波信号的IAVD几乎不受噪声的干扰,因此利用SSP算法能够有效地抵抗强噪声的干扰,精确地评估损伤散射的S0模式的ToF,并进一步结合三角定位算法成功地定位出铝板中的切缝缺陷.
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