Size effects on the mixed modes and defect modes for a nano-scale phononic crystal slab |
| |
Authors: | Jun JIN Ningdong HU Hongping HU |
| |
Institution: | 1. Department of Mechanics, School of Aerospace Engineering, Huazhong University of Science and Technology, Wuhan 430074, China;2. Hubei Key Laboratory of Engineering Structural Analysis and Safety Assessment, Huazhong University of Science and Technology, Wuhan 430074, China |
| |
Abstract: | The size-dependent band structure of an Si phononic crystal (PnC) slab with an air hole is studied by utilizing the non-classic wave equations of the nonlocal strain gradient theory (NSGT). The three-dimensional (3D) non-classic wave equations for the anisotropic material are derived according to the differential form of the NSGT. Based on the the general form of partial differential equation modules in COMSOL, a method is proposed to solve the non-classic wave equations. The bands of the in-plane modes and mixed modes are identified. The in-plane size effect and thickness effect on the band structure of the PnC slab are compared. It is found that the thickness effect only acts on the mixed modes. The relative width of the band gap is widened by the thickness effect. The effects of the geometric parameters on the thickness effect of the mixed modes are further studied, and a defect is introduced to the PnC supercell to reveal the influence of the size effects with stiffness-softening and stiffness-hardening on the defect modes. This study paves the way for studying and designing PnC slabs at nano-scale. |
| |
Keywords: | band structure phononic crystal (PnC) nonlocal strain gradient theory (NSGT) size effect |
|
| 点击此处可从《应用数学和力学(英文版)》浏览原始摘要信息 |
| 点击此处可从《应用数学和力学(英文版)》下载免费的PDF全文 |