Design And Compression Properties Of Sinusoidal Negative Poisson’s Ratio Structure By Laser Melting Forming

Negative Poisson’s ratio structures have different deformation behavior than ordinary materials,expanding(or contracting)in the direction perpendicular to the external force under uniaxial stretching(or compressing)conditions.This characteristic makes the structure itself exhibit many superior properties.Compared with traditional structures,the negative Poisson’s ratio structures are provided with stronger shear resistance,indentation resistance,fracture resistance and higher energy absorption capacity.As a light-weight and high-performance structure,the negative Poisson’s ratio structure has great application prospects in the fields of biomedicine,aerospace,automotive industry,and smart sensors.The rapid development of additive manufacturing technology has made the complex lattice structure that was difficult to manufacture in the early stage a reality,and has attracted extensive research.Among them,the negative Poisson’s ratio structure has also attracted widespread attention from researchers all over the world.Although researchers have achieved a lot of achievements in the study of negative Poisson’s ratio structures,it is still necessary to continue to develop new structures and explore the mechanical properties of new negative Poisson’s ratio structures to enrich the variety of negative Poisson’s ratio structures.Therefore,this paper designs a negative Poisson’s ratio unit cell structure composed of sinusoidal struts crosscombined through the forward design method,and calls it a sinusoidal negative Poisson’s ratio structure.The designed sinusoidal negative Poisson’s ratio structure was prepared by selective laser melting technology,and the research method combining finite element simulation and experiment was used to explore the influence of different design parameters(sine amplitude,porosity and cell size)on the mechanical properties and Poisson’s ratio of sinusoidal negative Poisson’s ratio structure under quasi-static uniaxial compression load law of influence;and reveal the deformation behavior of sinusoidal negative Poisson’s ratio structures and the mechanism of negative Poisson’s ratio behavior;finally,the mechanical properties and deformation behavior of the sinusoidal negative Poisson’s ratio structure under dynamic loads are further studied by constructing the finite element model of split Hopkinson pressure bar.The main research results of this paper are as follows:(1)The stress-strain curve of a sinusoidal negative Poisson’s ratio structure during quasi-static uniaxial compression can be divided into three stages,namely,the linear elastic stage,the stress plateau stage and the densification stage,in which the stress plateau stage has a stress Strengthening behavior,and a multi-segment sequentially enhanced stress plateau can be observed.(2)The sinusoidal amplitude,porosity and cell size have significant effects on the quasi-static compression properties and Poisson’s ratio of the sinusoidal negative Poisson’s ratio structure.Under the same conditions,the larger the sinusoidal amplitude and the higher the porosity,the lower the compressive capacity and energy absorption capacity of the sinusoidal negative Poisson’s ratio structure,but the more obvious the negative Poisson’s ratio effect;and the larger cell size,the stronger the compressive capacity and energy absorption capacity of the sinusoidal negative Poisson’s ratio structure,and the less significant the negative Poisson’s ratio effect.(3)The high strain rate load has a significant effect on the compressive strength and negative Poisson’s ratio effect of the sinusoidal negative Poisson’s ratio structure,and the compressive strain becomes larger with the increase of the strain rate.