De Luca Alessandro, Perfetto Donato, Lamanna Giuseppe, Aversano Antonio, Caputo Francesco
Department of Engineering, University of Campania "L. Vanvitelli", Via Roma 29, 81031 Aversa, Italy.
Materials (Basel). 2021 Dec 23;15(1):74. doi: 10.3390/ma15010074.
The aim of this work is to propose a numerical methodology based on the finite element (FE) method to investigate the dispersive behavior of guided waves transmitted, converted, and reflected by reinforced aluminum and composite structures, highlighting their differences. The dispersion curves of such modes can help designers in improving the damage detection sensitivity of Lamb wave based structural health monitoring (SHM) systems. A preliminary phase has been carried out to assess the reliability of the modelling technique. The accuracy of the results has been demonstrated for aluminum and composite flat panels by comparing them against experimental tests and semi-analytical data, respectively. Since the good agreement, the FE method has been used to analyze the phenomena of dispersion, scattering, and mode conversion in aluminum and composite panels characterized by a structural discontinuity, as a stiffener. The research activity allowed emphasizing modes conversion at the stiffener, offering new observations with respect to state of the art. Converted modes propagate with a slightly slower speed than the incident ones. Reflected waves, instead, have been found to travel with the same velocity of the incident ones. Moreover, waves reflected in the composite stiffened plate appeared different from those that occurred in the aluminum one for the aspects herein discussed.
这项工作的目的是提出一种基于有限元（FE）方法的数值方法，以研究导波在增强铝和复合材料结构中传播、转换和反射时的色散行为，突出它们之间的差异。这些模式的色散曲线有助于设计人员提高基于兰姆波的结构健康监测（SHM）系统的损伤检测灵敏度。已经进行了一个初步阶段来评估建模技术的可靠性。通过分别与实验测试和半解析数据进行比较，已证明了铝和复合平板结果的准确性。由于一致性良好，有限元方法已被用于分析以加劲肋作为结构不连续特征的铝和复合板中的色散、散射和模式转换现象。该研究活动强调了加劲肋处的模式转换，提供了相对于现有技术的新观察结果。转换后的模式传播速度比入射模式略慢。相反，已发现反射波以与入射波相同的速度传播。此外，对于本文讨论的方面，在复合加劲板中反射的波与在铝板中反射的波有所不同。
