Simulation Of Wave Propagation And In-Piane Impact Performance Of Curved And Chiral Hybrid Star-Shaped Structure

The lightweight chiral metamaterials have good vibration isolation performance,which can realize the suppression of elastic wave propagation in the low-frequency range.Concave metamaterials have a strong impact energy absorption ability and can be used as impact resistant materials to reduce structural damage.In this paper,a two-dimensional curved and chiral hybrid star-shaped structure is proposed by combining the characteristics of chirality and concave structures.In this paper,the characteristics of two-dimensional curved and chiral hybrid star-shaped structures are studied in terms of acoustic vibration isolation and mechanical impact.First of all,the finite element software to simulate the structure of the band diagram studies the boundary of the bandgap,and modal analysis of the generating mechanism of the bandgap.The relationship between wave attenuation characteristics and structural geometrical parameters and material parameters is also analyzed.It is found that the radius of the arc and the deflection angle of the connecting rod have significant effects on the frequency range of the bandgap of the structure.After that,simulated and calculated the dispersion surface,group velocity and phase velocity of the structure,and discussed the directional attenuation characteristics of the elastic wave in the plane and the direction of energy flow in the dispersion curve.It is found that the energy flow in the structure presents anisotropy.In a certain frequency range,the equivalent medium parameters satisfy the condition that shear wave and longitudinal wave produce negative refraction,so the structure also has double negative characteristics.In this paper,a two-dimensional curved and chiral hybrid star-shaped periodic plate structure is set up,and the filtering performance of the structure is verified by finite element simulation of transmission loss.Finally,the in-plane impact simulation was carried out on the structural specimen,the corresponding influence of impact velocity on the dynamic stress and compaction strain of the platform was analyzed,and the characteristics of energy absorption in the process of structural deformation were studied.Specimens with different radii,radius gradients,angles,and angle gradients were also set to study the influence of structural parameters on energy absorption.The results show that the designed two-dimensional curved and chiral hybrid star-shaped structure not only has good acoustic performance but also has impact resistance.This simple,single-phase lightweight structure has low-frequency wide bandgap and double negative acoustic characteristics.At the same time,the structure exhibits negative Poisson’s ratio effect and has a good energy absorption effect under impact load.The metamaterial can be used to manufacture lightweight acoustic lenses,filters,and other acoustic devices.It also has a broad application prospect in vibration and noise reduction and shock resistance of structures.