关键词: 单元网格密度, 材料阻尼, 高频导波, 群速度, 节点幅值叠加

Abstract: The low attenuation of high-frequency guided waves (greater than 1 MHz) in anchoring bolts makes it of great potential application value. However, the complexity of numerical calculation of high-frequency guided waves makes it very difficult to determine its propagation characteristics. It is not realistic to rely only on experiments to determine the optimal excitation wave in different anchorage bolts, so it is of great significance to establish a numerical model of high-frequency guided wave propagation. In this study, we first used the finite element software to construct a numerical model of the steel rod to examine the influence of the radial and axial element mesh density and material damping on the propagation process of high-frequency guided waves. And then, we employed the amplitude superposition and sum of all cross-section nodes as well as empirical mode decomposition (EMD) method to process data. Finally, we obtained the basic propagation characteristics of high-frequency guided waves in steel rods that are consistent with the theoretical results in the literature and experimental test results. The research results show that the element grid density, the setting of material damping value, and the vibration superposition of particles at different positions are the keys to reproducing the basic propagation characteristics of high-frequency guided waves.

Key words: cell grid density, material damping, high-frequency guided waves, group velocity, superposition of node amplitude