Inherent drawbacks associated with drug-eluting stents have prompted the development of bioresorbable cardiovascular stents.Additive manufacturing(3-dimentional(3D)printing)has been widely applied in medical devices.I...Inherent drawbacks associated with drug-eluting stents have prompted the development of bioresorbable cardiovascular stents.Additive manufacturing(3-dimentional(3D)printing)has been widely applied in medical devices.In this study,we develop a novel screw extrusion-based 3D printing system with a new designed mini-screw extruder to fabricate stents.A stent with a zero Poisson’s ratio(ZPR)structure is designed,and a preliminary monofilament test is conducted to investigate appropriate fabrication parameters.3D-printed stents with different geometric structures are fabricated and analyzed by observation of the surface morphology.An evaluation of the mechanical properties and a preliminary biological evaluation of 3D-printed stents with different parameters are carried out.In conclusion,the screw extrusion-based 3D printing system shows potential for customizable stent fabrication.展开更多
Intelligent structures like zero Poisson’s ratio(ZPR)cellular structures have been widely applied to the engineering fields such as morphing wings in recent decades,owing to their outstanding characteristics includin...Intelligent structures like zero Poisson’s ratio(ZPR)cellular structures have been widely applied to the engineering fields such as morphing wings in recent decades,owing to their outstanding characteristics including light weight and low effective modulus. In-plane and out-of-plane mechanical properties of ZPR cellular structures are investigated in this paper. A theoretical method for calculating in-plane tensile modulus,in-plane shear modulus and out-of-plane bending modulus of ZPR cellular structures is proposed,and the impacts of the unit cell geometrical configurations on in-plane tensile modulus,in-plane shear modulus and out-of-plane bending modulus are studied systematically based on finite element(FE)simulation. Experimental tests validate the feasibility and effectiveness of the theoretical and FE analysis. And the results show that the in-plane and out-of-plane mechanical properties of ZPR cellular structures can be manipulated by designing cell geometrical parameters.展开更多
Zero Poisson’s ratio(ZPR)mechanical metamaterials can yield no transverse displacements when unidi-rectionally compressed,and cylindrical sandwich meta-structures composed of semi re-entrant(SRE)ZPR metamaterials are...Zero Poisson’s ratio(ZPR)mechanical metamaterials can yield no transverse displacements when unidi-rectionally compressed,and cylindrical sandwich meta-structures composed of semi re-entrant(SRE)ZPR metamaterials are thus explored for applications on cylindrical shells of underwater equipment or sub-mersible structures.A group of ZPR unit cells with specified pre-strained wave propagation characteristics and adequate load-bearing capabilities is optimally designed based on the periodic boundary condition(PBC)and Bloch’s Theorem.The sound transmission and pressure-resistant performance of cylindrical sandwich meta-structures comprising the homogeneous and graded SRE ZPR unit cells are then investi-gated.The results show that the designed meta-structures can perfectly yield better vibroacoustic atten-uation behavior within the specified frequency regions corresponding to the pre-strained band gaps and safely bear the hydrostatic pressure equivalent to 1000 m depth with low weight-bulk ratios.In addition,the functionally graded metamaterial core can boost vibroacoustic performance within broader frequency ranges.展开更多
基金funding support from the Beijing Municipal Natural Science Foundation,China(Z150001)supported by Beijing Anzhen Hospital.
文摘Inherent drawbacks associated with drug-eluting stents have prompted the development of bioresorbable cardiovascular stents.Additive manufacturing(3-dimentional(3D)printing)has been widely applied in medical devices.In this study,we develop a novel screw extrusion-based 3D printing system with a new designed mini-screw extruder to fabricate stents.A stent with a zero Poisson’s ratio(ZPR)structure is designed,and a preliminary monofilament test is conducted to investigate appropriate fabrication parameters.3D-printed stents with different geometric structures are fabricated and analyzed by observation of the surface morphology.An evaluation of the mechanical properties and a preliminary biological evaluation of 3D-printed stents with different parameters are carried out.In conclusion,the screw extrusion-based 3D printing system shows potential for customizable stent fabrication.
基金supported by the National Natural Science Foundation of China(No.11872207)the Aeronautical Science Foundation of China (No. 20180952007)+1 种基金the Foundation of National Key Laboratory on Ship Vibration and Noise(No.614220400307)the National Key Research and Development Program of China (No.2019YFA708904)。
文摘Intelligent structures like zero Poisson’s ratio(ZPR)cellular structures have been widely applied to the engineering fields such as morphing wings in recent decades,owing to their outstanding characteristics including light weight and low effective modulus. In-plane and out-of-plane mechanical properties of ZPR cellular structures are investigated in this paper. A theoretical method for calculating in-plane tensile modulus,in-plane shear modulus and out-of-plane bending modulus of ZPR cellular structures is proposed,and the impacts of the unit cell geometrical configurations on in-plane tensile modulus,in-plane shear modulus and out-of-plane bending modulus are studied systematically based on finite element(FE)simulation. Experimental tests validate the feasibility and effectiveness of the theoretical and FE analysis. And the results show that the in-plane and out-of-plane mechanical properties of ZPR cellular structures can be manipulated by designing cell geometrical parameters.
基金support provided to the first author by the Natural Science Foundation of China(No.52201371)the Postdoctoral Science Foundation of China(No.2021M692043)the Postdoctoral Excellence Program of Shanghai(No.2021200)is gratefully acknowledged.
文摘Zero Poisson’s ratio(ZPR)mechanical metamaterials can yield no transverse displacements when unidi-rectionally compressed,and cylindrical sandwich meta-structures composed of semi re-entrant(SRE)ZPR metamaterials are thus explored for applications on cylindrical shells of underwater equipment or sub-mersible structures.A group of ZPR unit cells with specified pre-strained wave propagation characteristics and adequate load-bearing capabilities is optimally designed based on the periodic boundary condition(PBC)and Bloch’s Theorem.The sound transmission and pressure-resistant performance of cylindrical sandwich meta-structures comprising the homogeneous and graded SRE ZPR unit cells are then investi-gated.The results show that the designed meta-structures can perfectly yield better vibroacoustic atten-uation behavior within the specified frequency regions corresponding to the pre-strained band gaps and safely bear the hydrostatic pressure equivalent to 1000 m depth with low weight-bulk ratios.In addition,the functionally graded metamaterial core can boost vibroacoustic performance within broader frequency ranges.
