A proper lattice structure consisting of homogeneous material is designed in this paper to investigate the maximum bandwidth of perfect lattice structures and tunable property of waveguide with linear geometric defect by means of selecting optimal geometric lattice cell. A simulation model based on finite element method is used to calculate dispersion curves and transmission spectrums of lattice structures with different geometric parameters. Meanwhile, a simplified theoretical model of unit cell, which considers the mass of grid bar and stiffness of node area, is applied to validate the accuracy of simulation result and may provide an effective approach for prediction of band gap lower boundary. Then, the validated numerical results show different orders of widest band gap that can be realized by different optimal geometric structures. Moreover, waveguide property can be effectively controlled and manipulated by changing defect parameters. The present study may establish theoretical and simulation foundation to control and manipulate band structures and other acoustic propagation characteristics of waveguide devices.

中文翻译：

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周期性网格结构中可调带隙和波导的几何优化

本文设计了一种由均质材料构成的合适的晶格结构，通过选择最优几何晶格单元来研究完美晶格结构的最大带宽和具有线性几何缺陷的波导的可调谐特性。采用基于有限元法的仿真模型计算不同几何参数的晶格结构的色散曲线和透射谱。同时，采用考虑网格条质量和节点区域刚度的简化晶胞理论模型验证了模拟结果的准确性，为带隙下边界的预测提供了一种有效的方法。然后，经过验证的数值结果显示了可以通过不同的最佳几何结构实现的不同数量级的最宽禁带宽度。而且，通过改变缺陷参数可以有效地控制和操纵波导特性。本研究可为控制和操纵波导器件的能带结构和其他声传播特性奠定理论和仿真基础。