混沌腔体换能器在反向滤波弹性检测中的应用及其仿真研究

Application of a chaotic cavity transducer in inversal filter elastic detection and numercial simulation research

针对传统单通道时间反转无损检测成像质量低,检测灵敏度差的问题,通过混沌腔体换能器(Chaotic Cavity Transducer:CCT)的应用,极大提高聚焦检测的能力。CCT的使用可以更好的利用介质的各经历态特性,其有效解决了单通道时间反转检测中的幻影成像及边界应力增加的问题。实验过程中采用了线性调频激发信号源(Chirped Excitation:CE)及反向滤波技术(Inverse Filter:IF),他们分别能够携带更多的能量及利用更多反转信号的模态,进而有效的提高信号聚焦的质量。为了更好的理解混沌腔体换能器的特性,采用了非连续Galerkin算法对其聚焦性能进行了数值仿真和分析。数值仿真的结果及混响介质检测与成像的实现,验证了CCT与CE及IF结合应用的有效性和高效性。

Addressing the problems of low quality focalization and low efficency of detection in traditional one channel time reversal Nondestructive Testing （NDT）, a Chaotic Cavity Transducer （CCT） has been proposed and employed to improve focalization and detection. The CCT takes advantage of a medium＇s inherent ergodicity, solving the problems of ＂phantom＂ image and increased strain at the boundary of test media. For improved focalization, the Chirped Excitation （CE） source signal and Inverse Filter （IF） technique were used. CE leads to enhanced energy transfer into the test sample, while an IF uses more eigenmodes of reversal signal. In order to better understand the properties of CCT, numerical simulations were carried out using the nodal Discontinuous Galerkin Finite Element Method （DG-FEM）. Results of numerical simulation of the CCT and the realization of image detection on reverberant raedium confirmed the high quality focalization and high efficency resulting from the combined implementation of CCT, CE and IF.