From the general formula for calculating the efficiency of planetary geartrains, the efficiency of the double crank ring-plate-type pin-cycloidal gear planetary drive isderived. To prove the theory, an experimental st...From the general formula for calculating the efficiency of planetary geartrains, the efficiency of the double crank ring-plate-type pin-cycloidal gear planetary drive isderived. To prove the theory, an experimental study has been conducted. The tested value of theefficiency of a sample set of the new-type drive in the experiment agrees with the calculated one.It shows that the new-type drive is of not merely high bearing capacity, but also quite highefficiency.展开更多
A dynamic quasi-continuum model is presented to analyze free vibration of plate-type cubic crystal nano-materials.According to the Hamilton principle,fundamental governing equations in terms of displacement components...A dynamic quasi-continuum model is presented to analyze free vibration of plate-type cubic crystal nano-materials.According to the Hamilton principle,fundamental governing equations in terms of displacement components and angles of rotations are given.As an application of the model,the cylindrical bending deformation of the structure fixed at two ends is analyzed,and a theoretical formula evaluating the fundamental frequency is obtained by using Galerkin's method.Meanwhile,the solution for the classical continuous plate model is also derived,and the size-dependent elastic modulus and Poisson's ratio are taken in computation.The frequencies corresponding to different atomic layers are numerically presented for the plate-type NaC l nano-materials.Furthermore,a molecular dynamics(MD)simulation is conducted with the code LAMMPS.The comparison shows that the present quasi-continuum model is valid,and it may be used as an alternative model,which reflects scale effects in analyzing dynamic behaviors of such plate-type nano-materials.展开更多
Several types of acoustic metamaterial(AM)plates have been developed to achieve low-frequency and wide bandgaps,which are adjusted by their geometric configurations and material properties.This paper combines the clas...Several types of acoustic metamaterial(AM)plates have been developed to achieve low-frequency and wide bandgaps,which are adjusted by their geometric configurations and material properties.This paper combines the classical plate theory and the characteristics of piezoelectric materials,and uses the plane wave expansion method(PWEM)to derive the bandgap theoretical model of plate-type metastructures.The dispersion curves of the structures composed of elastic materials,piezoelectric materials,and functionally graded(FG)materials are compared and studied,and verified with the finite element simulation results.Then,the effects of temperatures,piezoelectric parameters,scatterer shapes,scatterer distributions,scatterer tapers,rubber layers,and spiral groove configurations on the bandgap of plate-type metastructures are discussed,and the material and geometric parameters are optimized with the genetic algorithm(GA).This study provides a reference for the design of low-frequency broadband structures.展开更多
基金This project is supported by National Natural Science Foundation of China (No.50175011).
文摘From the general formula for calculating the efficiency of planetary geartrains, the efficiency of the double crank ring-plate-type pin-cycloidal gear planetary drive isderived. To prove the theory, an experimental study has been conducted. The tested value of theefficiency of a sample set of the new-type drive in the experiment agrees with the calculated one.It shows that the new-type drive is of not merely high bearing capacity, but also quite highefficiency.
文摘A dynamic quasi-continuum model is presented to analyze free vibration of plate-type cubic crystal nano-materials.According to the Hamilton principle,fundamental governing equations in terms of displacement components and angles of rotations are given.As an application of the model,the cylindrical bending deformation of the structure fixed at two ends is analyzed,and a theoretical formula evaluating the fundamental frequency is obtained by using Galerkin's method.Meanwhile,the solution for the classical continuous plate model is also derived,and the size-dependent elastic modulus and Poisson's ratio are taken in computation.The frequencies corresponding to different atomic layers are numerically presented for the plate-type NaC l nano-materials.Furthermore,a molecular dynamics(MD)simulation is conducted with the code LAMMPS.The comparison shows that the present quasi-continuum model is valid,and it may be used as an alternative model,which reflects scale effects in analyzing dynamic behaviors of such plate-type nano-materials.
文摘Several types of acoustic metamaterial(AM)plates have been developed to achieve low-frequency and wide bandgaps,which are adjusted by their geometric configurations and material properties.This paper combines the classical plate theory and the characteristics of piezoelectric materials,and uses the plane wave expansion method(PWEM)to derive the bandgap theoretical model of plate-type metastructures.The dispersion curves of the structures composed of elastic materials,piezoelectric materials,and functionally graded(FG)materials are compared and studied,and verified with the finite element simulation results.Then,the effects of temperatures,piezoelectric parameters,scatterer shapes,scatterer distributions,scatterer tapers,rubber layers,and spiral groove configurations on the bandgap of plate-type metastructures are discussed,and the material and geometric parameters are optimized with the genetic algorithm(GA).This study provides a reference for the design of low-frequency broadband structures.
