Miniaci M, Gliozzi A S, Morvan B, Krushynska A, Bosia F, Scalerandi M, Pugno N M
University of Le Havre, Laboratoire Ondes et Milieux Complexes, UMR CNRS 6294, 75 Rue Bellot, 76600 Le Havre, France.
Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy.
Phys Rev Lett. 2017 May 26;118(21):214301. doi: 10.1103/PhysRevLett.118.214301.
The appearance of nonlinear effects in elastic wave propagation is one of the most reliable and sensitive indicators of the onset of material damage. However, these effects are usually very small and can be detected only using cumbersome digital signal processing techniques. Here, we propose and experimentally validate an alternative approach, using the filtering and focusing properties of phononic crystals to naturally select and reflect the higher harmonics generated by nonlinear effects, enabling the realization of time-reversal procedures for nonlinear elastic source detection. The proposed device demonstrates its potential as an efficient, compact, portable, passive apparatus for nonlinear elastic wave sensing and damage detection.
弹性波传播中非线性效应的出现是材料损伤开始的最可靠、最敏感的指标之一。然而，这些效应通常非常小，只能使用繁琐的数字信号处理技术才能检测到。在此，我们提出并通过实验验证了一种替代方法，利用声子晶体的滤波和聚焦特性自然地选择并反射由非线性效应产生的高次谐波，从而实现用于非线性弹性源检测的时间反转过程。所提出的装置展示了其作为一种用于非线性弹性波传感和损伤检测的高效、紧凑、便携、无源设备的潜力。
