超声导波在大型薄铝板缺陷检测中的应用

 为了提高大型薄板超声检测的速度，研究了超声导波及其在大型薄铝板缺陷检测中的应用。推导了超声导波在大型薄铝板中传播的理论模型，分析了导波的波结构，设计并实践了导波检测薄铝板缺陷的方法。试验结果表明，若选取S0导波模式对1 mm薄铝板进行线扫描检测，在有缺陷的地方会出现明显的回波信号。根据缺陷回波与板端回波的传播时间差，可计算出缺陷的位置。缺陷越大，缺陷回波信号幅值越大。选择对缺陷灵敏度高的导波模式，导波法线扫描检测方式可以有效缩短检测时间，提高检测效率。

Application of Ultrasonic Guided Waves to Defect Inspection of Large Thin Aluminum Plate

To increase the speed of ultrasonic inspection for large thin plate,the ultrasonic guided waves and their applications to the defect inspection of large thin aluminum plate are studied.The theoretical model of guided waves propagated in large aluminum plate is presented.The wave structures of guided waves are analyzed.A method of detecting flaws in large thin aluminum plate with guided waves is designed and practiced.Experiment results indicate that the apparent reflect waves appear responding to the defect position in a 1 mm thick aluminum plate with S0 mode.The defect position can be evaluated in term of the time between the defect waves and reflect waves from plate edge.The larger the defect size is,the lager the reflect waves are.With guided wave modes sensitive to the defect,the line-scan method of guided waves is considerable in saving of testing time and the speed of ultrasonic testing for large plate can be improved effectively.