引入环形压电阵列及主动 Lamb波损伤概率检测成像算法(reconstruction algorithm for probabilistic inspection of damage,简称RAPID)监测技术对金属结构裂纹损伤的定量监测进行研究.基于裂纹损伤对响应信号直达波的作用机理,根据裂纹损伤对交叉监测路径下的响应信号变化差异性,提出十字交叉扫描方法判定裂纹方向,进而对平行或近似平行裂纹的监测路径的损伤差异性系数(signal difference coefficient,简称SDC)值进行校正,强化了裂纹方向的重构信息,完成了裂纹损伤的图像重构和定量化评估.针对不同位置及方向裂纹的监测和成像,在铝板上进行了实验验证.结果表明,提出的十字交叉扫描方法以及改进RAPID成像方法较好地识别了裂纹方向,能够定量显示裂纹长度.
Ring piezoelectric array and active Lamb wave reconstruction algorithm for probabilistic inspection of damage(RAPID)imaging is introduced to study the metal structure crack damage quantitative monitoring.Based on the mechanism that direct wave signal specifically responses to different damage,the difference of crack damage to the response signal changes under the orthogonal monitoring path,a cross scanning method is proposed to determine the damage direction,and then adjust the signal difference coefficient(SDC)value of damage with parallelly-passing or approximately parallelly-passing path.The proposed method constructs image information of reinforced damage orientation,then realize the image reconstruction and quantitative evaluation of crack damage.Experimental verification is carried out on the aluminum plate,aiming at the monitoring and im-aging of cracks in different positions and directions.The experiment results indicate that the proposed cross scan-ning method and the improved RAPID imaging method can better identify the crack direction and can quantita-tively display the crack length.