In-plane crushing behavior and energy absorption design of composite honeycombs

Theoretical analysis and numerical simulation methods were used to study the in-plane crushing behavior of single-cell structures and regular and composite honeycombs.Square,hexagonal,and circular honeycombs were selected as honeycomb layers to establish composite honeycomb models in the form of composite structures and realize the complementary advantages of honeycombs with type Ⅰ and type Ⅱ structures.The effects of honeycomb layer arrangement,plastic collapse strength,relative density,and crushing velocity on the deformation mode,plateau stress,load uniformity,and energy absorption performance of the composite honeycombs were mainly considered.A semi-empirical formula for plateau stress and energy absorption rate per unit mass for the composite honeycombs was developed.The results showed that the arrangement mode of honeycomb layers is an important factor that affects their mechanical properties.Appropriately selecting the arrangement of honeycomb layers and the proportion of honeycomb layers with different structures in a composite honeycomb can effectively improve its load uniformity and control the magnitude of plateau stress and energy absorption capacity.

半导体中相干亚毫米波的产生和传播

研究了超短光脉冲在GaAs表面激发相干亚毫米波振幅随入射角变化的规律，前后向辐射比值随入射角度变化的规律，实验测量了在GaAs表面镀上极薄金属薄膜后所产生的相干亚毫米波振幅对薄膜厚度的依赖关系；利用光生载流子偶极辐射的理论模型成功地解释了实验得到的角度依赖关系和相干亚毫米波的偏振特性。