Ciampa Francesco, Scarselli Gennaro, Pickering Simon, Meo M
Department of Mechanical Engineering, University of Bath, Bath BA2 7AY, UK.
Department of Engineering for Innovation, University of Salento, via per Monteroni, Lecce 73100, Italy.
Ultrasonics. 2015 Sep;62:147-55. doi: 10.1016/j.ultras.2015.05.011. Epub 2015 May 23.
This paper presents a nonlinear elastic wave tomography method, based on ultrasonic guided waves, for the image of nonlinear signatures in the dynamic response of a damaged isotropic structure. The proposed technique relies on a combination of high order statistics and a radial basis function approach. The bicoherence of ultrasonic waveforms originated by a harmonic excitation was used to characterise the second order nonlinear signature contained in the measured signals due to the presence of surface corrosion. Then, a radial basis function interpolation was employed to achieve an effective visualisation of the damage over the panel using only a limited number of receiver sensors. The robustness of the proposed nonlinear imaging method was experimentally demonstrated on a damaged 2024 aluminium panel, and the nonlinear source location was detected with a high level of accuracy, even with few receiving elements. Compared to five standard ultrasonic imaging methods, this nonlinear tomography technique does not require any baseline with the undamaged structure for the evaluation of the corrosion damage, nor a priori knowledge of the mechanical properties of the specimen.
本文提出了一种基于超声导波的非线性弹性波层析成像方法，用于对受损各向同性结构动态响应中的非线性特征进行成像。所提出的技术依赖于高阶统计量和径向基函数方法的结合。由谐波激励产生的超声波形的双相干性用于表征由于表面腐蚀而在测量信号中包含的二阶非线性特征。然后，采用径向基函数插值法，仅使用有限数量的接收传感器就能在面板上实现对损伤的有效可视化。在受损的2024铝面板上通过实验证明了所提出的非线性成像方法的稳健性，即使接收元件很少，也能高精度地检测到非线性源位置。与五种标准超声成像方法相比，这种非线性层析成像技术在评估腐蚀损伤时不需要与未受损结构的任何基线，也不需要试样力学性能的先验知识。
