Fromme Paul, Wilcox Paul D, Lowe Michael J S, Cawley Peter
Department of Mechanical Engineering, University College London, WC1E 7JE, UK.
IEEE Trans Ultrason Ferroelectr Freq Control. 2006 Apr;53(4):777-85.
The prototype of a guided ultrasonic wave array for the structural integrity monitoring of large, plate-like structures has been designed, built, and tested. The development of suitably small transducers for the excitation and measurement of the first antisymmetric Lamb wave mode Ao is described. The array design consists of a ring of 32 transducers, permanently bonded to the structure with a protective membrane, in a compact housing with the necessary multiplexing electronics. Using a phased addition algorithm with dispersion compensation and deconvolution in the wavenumber domain, a good dynamic range can be achieved with a limited number of transducers. Limitations in the transducer design and manufacture restricted the overall dynamic range achieved to 27 dB. Laboratory measurements for a steel plate containing various defects have been performed. The results for standard defects are compared to theoretical predictions and the sensitivity of the array device for defect detection has been established. Simulated corrosion pitting and a defect cut with an angle grinder simulating general corrosion were detected.
已设计、制造并测试了用于大型板状结构结构完整性监测的导波超声阵列原型。描述了用于激发和测量第一反对称兰姆波模式Ao的尺寸合适的小型换能器的研制情况。该阵列设计由32个换能器组成的环构成，通过保护膜永久粘结到结构上，置于带有必要复用电子设备的紧凑外壳中。在波数域中使用具有色散补偿和反卷积的相加法算法，用有限数量的换能器即可实现良好的动态范围。换能器设计和制造方面的限制使实现的总体动态范围限制在27 dB。已对含有各种缺陷的钢板进行了实验室测量。将标准缺陷的测量结果与理论预测进行了比较，并确定了阵列装置检测缺陷的灵敏度。检测到了模拟的腐蚀点蚀以及用角磨机切割模拟一般腐蚀的缺陷。
