Metamaterials are defined as artificially designed micro-architectures with unusual physical properties,including optical,electromagnetic,mechanical,and thermal characteristics.This study investigates the compressive ...Metamaterials are defined as artificially designed micro-architectures with unusual physical properties,including optical,electromagnetic,mechanical,and thermal characteristics.This study investigates the compressive mechanical and heat transfer properties of AlSi10Mg gradient metamaterials fabricated by Laser Powder Bed Fusion(LPBF).The morphology of the AlSi10Mg metamaterials was examined using an ultrahigh-resolution microscope.Quasi-static uniaxial compression tests were conducted at room temperature,with deformation behavior captured through camera recordings.The findings indicate that the proposed gradient metamaterial exhibits superior compressive strength properties and energy absorption capacity.The Gradient-SplitP structure demonstrated better compressive performance compared to other strut-based structures,including Gradient-Gyroid and Gradient-Lidinoid structures.With an apparent density of 0.796,the Gradient-SplitP structure exhibited an outstanding energy absorption capacity,reaching an impressive 23.57 MJ/m^(3).In addition,heat conductivity tests were performed to assess the thermal resistance of these structures with different cell configurations.The gradient metamaterials exhibited higher thermal resistance and lower thermal conductivity.Consequently,the designed gradient metamaterials can be considered valuable in various applications,such as thermal management,load-bearing,and energy absorption components.展开更多
This study aims to discuss the propagation characteristics of seismic Lamb wave and surface wave in a new radial gradient supercell seismic metamaterial(RGSSM).Different from the traditional seismic metamaterials with...This study aims to discuss the propagation characteristics of seismic Lamb wave and surface wave in a new radial gradient supercell seismic metamaterial(RGSSM).Different from the traditional seismic metamaterials with simple unit cells,the RGSSM consists of the supercells arranged periodically along the radial direction,and these supercells are composed of five kinds of unit cells with gradient filling rates.The dispersion curve and attenuation spectrum of the Lamb wave in RGSSM are studied with the finite element method combined with the supercell technology,generating a very low-frequency ultra-wide bandgap of 3.98-20 Hz,and a forbidden band generated by the localized modes forms multi-harmonic oscillators inside the supercell.Furthermore,it is found that the Young’s modulus of the soil is more sensitive to the effect of bandgap.In terms of surface wave,the RGSSM can produce rapid attenuation in the low frequency range of 5.2-8.5 Hz.Finally,a 3D model is designed to demonstrate the shielding performance of RGSSM against the seismic surface wave.The proposed RGSSM provides a new idea for the seismic isolation of ultra-wide and low-frequency seismic waves.展开更多
A polarization-insensitive unidirectional spoof surface plasmon polariton（SPP） coupler mediated by a gradient metasurface is proposed. The field distributions and average Poynting vector of the coupled spoof SPPs ar...A polarization-insensitive unidirectional spoof surface plasmon polariton（SPP） coupler mediated by a gradient metasurface is proposed. The field distributions and average Poynting vector of the coupled spoof SPPs are analyzed. The simulated and experimental results support the theoretical analysis and indicate that the designed gradient metasurface can couple both the parallel-polarized and normally-polarized incident waves to the spoof SPPs propagating in the same direction at about 5 GHz.展开更多
基金Supported by National Natural Science Foundation of China(Grant No.12272045)the BIT Research and Innovation Promoting Project(Grant No.2023YCXZ025).
文摘Metamaterials are defined as artificially designed micro-architectures with unusual physical properties,including optical,electromagnetic,mechanical,and thermal characteristics.This study investigates the compressive mechanical and heat transfer properties of AlSi10Mg gradient metamaterials fabricated by Laser Powder Bed Fusion(LPBF).The morphology of the AlSi10Mg metamaterials was examined using an ultrahigh-resolution microscope.Quasi-static uniaxial compression tests were conducted at room temperature,with deformation behavior captured through camera recordings.The findings indicate that the proposed gradient metamaterial exhibits superior compressive strength properties and energy absorption capacity.The Gradient-SplitP structure demonstrated better compressive performance compared to other strut-based structures,including Gradient-Gyroid and Gradient-Lidinoid structures.With an apparent density of 0.796,the Gradient-SplitP structure exhibited an outstanding energy absorption capacity,reaching an impressive 23.57 MJ/m^(3).In addition,heat conductivity tests were performed to assess the thermal resistance of these structures with different cell configurations.The gradient metamaterials exhibited higher thermal resistance and lower thermal conductivity.Consequently,the designed gradient metamaterials can be considered valuable in various applications,such as thermal management,load-bearing,and energy absorption components.
文摘This study aims to discuss the propagation characteristics of seismic Lamb wave and surface wave in a new radial gradient supercell seismic metamaterial(RGSSM).Different from the traditional seismic metamaterials with simple unit cells,the RGSSM consists of the supercells arranged periodically along the radial direction,and these supercells are composed of five kinds of unit cells with gradient filling rates.The dispersion curve and attenuation spectrum of the Lamb wave in RGSSM are studied with the finite element method combined with the supercell technology,generating a very low-frequency ultra-wide bandgap of 3.98-20 Hz,and a forbidden band generated by the localized modes forms multi-harmonic oscillators inside the supercell.Furthermore,it is found that the Young’s modulus of the soil is more sensitive to the effect of bandgap.In terms of surface wave,the RGSSM can produce rapid attenuation in the low frequency range of 5.2-8.5 Hz.Finally,a 3D model is designed to demonstrate the shielding performance of RGSSM against the seismic surface wave.The proposed RGSSM provides a new idea for the seismic isolation of ultra-wide and low-frequency seismic waves.
基金Project supported by the China Postdoctoral Science Foundation(Grant No.2015M580849)the National Natural Science Foundation of China(Grant Nos.61471292,61501365,61471388,6133100541404095,and 41390454)
文摘A polarization-insensitive unidirectional spoof surface plasmon polariton（SPP） coupler mediated by a gradient metasurface is proposed. The field distributions and average Poynting vector of the coupled spoof SPPs are analyzed. The simulated and experimental results support the theoretical analysis and indicate that the designed gradient metasurface can couple both the parallel-polarized and normally-polarized incident waves to the spoof SPPs propagating in the same direction at about 5 GHz.
