【摘要】 发展一种基于原子尺度的有限元动力学方程,其动态行为跨越了从原子尺度到宏观尺度.理论计算该方程的色散关系和动力学散射特征.在此基础上,基于滤波器的概念,设计低通滤波边界条件用于减少网格增大带来的高频反射波,同时又保证低频振动波传播不受影响.通过一维数值模拟,计算了能量反射和透射系数,展示低通滤波边界条件可以吸收高频反射波而不影响低频波的传播.更多还原

【Abstract】 An atomic-based finite element method is developed,spanning from atomic scale to macroscopic one. With theoretical deduction dispersion relation and dynamic scattering behavior are calculated. For spurious reflection caused by non-uniform grid,lowpass filter boundary condition is designed to effectively eliminate the reflection of high-frequency phonons,while keeping low-frequency ones transparent. These schemes are demonstrated with numerically calculating reflection and transmission coefficients in onedimensional modeling.更多还原