Study On Damping Performance Of Negative Poisson's Ratio Metamaterials

The negative Poisson's ratio metamaterial structures has become the mainstream direction of domestic and foreign scholars because of its excellent energy absorption characteristics.However,the current research results mainly focus on the static performance and impact energy absorption of the structure.The damping performance of the structures are also limited to the study of conventional hexagonal concave honeycombs and arrow honeycomb structures.This thesis is from the research institute to ensure that the deformable mirror driver is not damaged under the aerospace launch vibration.This thesis mainly analyzed the damping performance of a new type of negative Poisson's ratio metamaterials-sinusoidal metamaterials.The structural dimensions of standard two-dimensional and three-dimensional sinusoidal metamaterials were determined.The geometrical dimensions of the standard two-dimensional structures are the wall thickness of the structure and the magnitude of the sinusoid.The geometry variable of a standard three-dimensional structures is the magnitude of the sinusoid.Based on this,several special structures are proposed.Subsequently,the calculation method of the equivalent Poisson's ratio of two-dimensional and three-dimensional structures in the case of large deformation is introduced.The finite element software was used to simulate the stretching and compression of the structure.And the equivalent Poisson's ratio of the structure was calculated using the formula.The influence of the geometric parameters of the structure on the equivalent Poisson's ratio was found by analysis.In order to analyzed the influence of geometric parameters on the vibration damping performance of two-dimensional and three-dimensional sinusoidal metamaterials,the finite element modal analysis method was used to analyze the natural frequency and damping loss factor of the structure.The damping loss factor of a three-dimensional structure is generally larger than that of a two-dimensional structure.Aiming at the problem that the deformable mirror might be destroyed under the vibration of space launch,the vibration damping performance based on two-dimensional and three-dimensional sinusoidal metamaterials was analyzed.The acceleration response under harmonic and random vibrations was analyzed using finite element software.Comparing the results of the response with the expected indicators,it was found that the vibration damping base has obvious damping effect under actual conditions,but there was still a certain gap with the expected indicators.Because the use of a sinusoidal metamaterial structure did not meet the actual vibration reduction requirements,a way to arrange the sinusoidal metamaterial structure regularly was proposed.Through analysis,it was found that a reasonable combination of sinusoidal metamaterial structure can achieve better vibration damping effect.This discovery provided an optimized and improved direction for the deformable mirror damping base.Stereo Lithography Appearance(SLA) was used to process the vibration absorber base,and it was found that the processing accuracy of the two-dimensional structure formed by this technology is very high,while the processing of the three-dimensional structure deviates greatly from the designed structure size.