Elastic wave propagation in 2D-FGM hollow cylinders with curved outer surface under moving shock loading using isogeometric analysis

Author(s):  
Ahmad Yavari ◽  
Mohammad Hossein Abolbashari ◽  
Behrooz Hassani

Analysis of elastic wave propagation in a hollow cylinder with two-dimensional (2D) functionally graded material (FGM) and the curved outer surface under internal moving shock loading is the subject of this study. In the proposed method, there is no restriction on the distribution of material properties, the shape of the outer surface, and the applied shock loading. They are treated with non-uniform rational B-spline (NURBS). The isogeometric approach is developed for solving the problem to ensure precise modeling of the geometry. Also, the Newmark approach is used for full discretization of the isogeometric equations. The distributions of all elastic field quantities are determined for two types of material distributions and shock loadings. The effects of shock loadings, the shape of the outer surface, and the material distribution on the elastic wave are thoroughly examined. Propagation, reflections, and propagation speed inside the hollow cylinder are investigated. It is found that the propagation speeds of elastic waves have a distribution associated with the distribution of the material properties. Also, the shape of the outer surface can affect the amplitude of the elastic wave and the locations of concentration stress. It is concluded that the sonic boom phenomenon occurs in the solids as well as in the air.

2020 ◽  
Vol 231 (8) ◽  
pp. 3363-3385 ◽  
Author(s):  
Soroush Sepehri ◽  
Hamid Jafari ◽  
Mahmoud Mosavi Mashhadi ◽  
Mohammad Reza Hairi Yazdi ◽  
Mir Masoud Seyyed Fakhrabadi

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.


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