Elastic metamaterials are of growing interest due to their unique effective properties and wave manipulation abilities.Unlike phononic crystals based on the Bragg scattering mechanism,elastic metamaterials(EMMs)are ba...Elastic metamaterials are of growing interest due to their unique effective properties and wave manipulation abilities.Unlike phononic crystals based on the Bragg scattering mechanism,elastic metamaterials(EMMs)are based on the locally resonant(LR)mechanism and can fully control elastic waves at a subwavelength scale.Microstructural designs of EMMs in plate-like structures have attracted a great deal of attention.In this paper,the recent advances in the microstructural designs of LRbased EMM plates are reviewed.Their potential applications in the fields of low frequency guided wave attenuation,wave manipulation and energy trapping at a subwavelength scale,and structural health monitoring are discussed.展开更多
The fracture behavior and mechanism of PST crystals of a Ti 49%(mole fraction)Al alloy have been studied by using in situ straining and micromechanical calculation. The three dimensional micromechanical model represen...The fracture behavior and mechanism of PST crystals of a Ti 49%(mole fraction)Al alloy have been studied by using in situ straining and micromechanical calculation. The three dimensional micromechanical model representing the structure of PST crystal has been built, and the stress distribution ahead of the sharp and blunt crack tips either parallel to lamellar interface or perpendicular to the lamellae has been calculated by using finite element method based on linear elasticity of PST crystals. The experimental results show that the fracture behaviors and mechanisms are strongly dependent on the angle of loading axis to the lamellae. The calculation indicates that nucleation and propagation of microcrack along the interfaces are controlled by the normal stress and translamellar microcrack is controlled by shear stress ahead of crack tip.展开更多
基金supported by the Air Force Office of Scientific Research[grant no.AF 9550-15-1-0061] with Program Manager Dr.Byung-Lip(Les)Leethe National Natural Science Foundation of China[grants no.11221202,11290153,11372035].
文摘Elastic metamaterials are of growing interest due to their unique effective properties and wave manipulation abilities.Unlike phononic crystals based on the Bragg scattering mechanism,elastic metamaterials(EMMs)are based on the locally resonant(LR)mechanism and can fully control elastic waves at a subwavelength scale.Microstructural designs of EMMs in plate-like structures have attracted a great deal of attention.In this paper,the recent advances in the microstructural designs of LRbased EMM plates are reviewed.Their potential applications in the fields of low frequency guided wave attenuation,wave manipulation and energy trapping at a subwavelength scale,and structural health monitoring are discussed.
文摘The fracture behavior and mechanism of PST crystals of a Ti 49%(mole fraction)Al alloy have been studied by using in situ straining and micromechanical calculation. The three dimensional micromechanical model representing the structure of PST crystal has been built, and the stress distribution ahead of the sharp and blunt crack tips either parallel to lamellar interface or perpendicular to the lamellae has been calculated by using finite element method based on linear elasticity of PST crystals. The experimental results show that the fracture behaviors and mechanisms are strongly dependent on the angle of loading axis to the lamellae. The calculation indicates that nucleation and propagation of microcrack along the interfaces are controlled by the normal stress and translamellar microcrack is controlled by shear stress ahead of crack tip.
