scholarly journals Numerical Study of Elastic Wave Propagation Characteristics in Cracked Rock

2014 ◽  
Vol 02 (06) ◽  
pp. 391-396
Author(s):  
Kaifeng Han ◽  
Ruiqi Cao
2020 ◽  
Vol 56 (1) ◽  
pp. 18-28
Author(s):  
He-Xiang Wu ◽  
Xin-Chun Zhang ◽  
Ying Liu

In contrast to the dynamic response characteristics, few propagation characteristics of elastic waves have been described on cellular materials, to date. In view of the development trend of emerging metamaterials on multi-functional, detailed characterization of elastic wave in honeycombs becomes an important task in order to assess their performances. This study investigates the propagation characteristics of elastic wave in square-packed circular honeycombs through combining theoretical analysis and numerical simulation. We also establish a one-dimensional circular chain model to discuss the influence mechanism of impact velocities, material parameters, and structural parameters on the elastic wave propagation characteristics in square-packed circular honeycombs. The influence relations are quantified and a semi-empirical theoretical expression for assessing characterization is presented, which extends theory of elastic wave propagation speed from solid materials to square-packed circular honeycombs. The assessment equation fully describes the elastic wave propagation speed and stress amplitude variation with location during propagation in square-packed circular honeycombs, and the results are consistent with the experimental data from the literature. The findings herein are aimed at providing an assessment equation with simple form for engineering applications easily and providing theoretical basis for elastic wave control and multi-functional combination design of metamaterials.


2018 ◽  
Vol 25 (3) ◽  
pp. 517-528 ◽  
Author(s):  
Ping Wang ◽  
Qiang Yi ◽  
Caiyou Zhao ◽  
Mengting Xing

Wave propagation in the ordered and randomly disordered periodic track structure in high-speed railways are investigated theoretically and experimentally. Taking the CRTS-I double-block ballastless track structure in China as the research object, a theoretical model of periodic track structure is established. The rail is modelled as a Timoshenko beam considering the bending–torsional coupling. The dispersion curves of the periodic track structure are obtained according to the transfer matrix method and Bloch theory. Based on the Lyapunov exponent algorithm, the elastic wave propagation characteristics of the randomly disordered periodic track structure are further calculated and analyzed considering the random disorder of structure parameters. The obtained results show that the periodic track structure is characterized by band gaps, elastic wave propagation attenuates significantly within the band gap, and random disorder in the track structure can expand the attenuation regions. Finally, the band gap characteristics of the vertical/lateral flexural wave and torsional wave are verified respectively through an in situ experiment.


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