Design And Research Of Programmable Poisson's Ratio Lattice Structure Based On Shape Memory Polymer

The shape memory polymer material is a high polymer,which can produce a memory effect on the shape of the structure,and has the advantages of light weight and high shape recovery rate.The shape memory polymer material has been widely used in biomedicine,aerospace and other fields.The lattice structure has the characteristics of light weight,high specific strength and high specific stiffness,and its open and continuous space provides conditions for the burial of multi-functional devices.It has been widely used in many fields such as aerospace and construction facilities.However,there is little research on the combination of shape memory materials and lattice structures.Combination of these two topics can maximize the application scope of them and realize the active deformation of the lattice structure and the active change of performance characteristics.In this paper,the 3D printed carbon short fiber reinforced polylactic acid material is tested for static mechanical properties,dynamic mechanical properties,differential scanning calorimetry,shape memory performance,and relaxation performance to obtain the elastic modulus,glass transition temperature,shape memory performance,stress relaxation curve and so on of the material.Inspired by the arrow-shaped negative Poisson's ratio lattice structure,a new zero-Poisson's ratio lattice structure is proposed that can maintain a stable value of zero Poisson's ratio under large deformation,the expression of its relative density is derived,and the relationship between relative density and geometric parameters of lattice structure is explored;the relationship between its elastic equivalent mechanical properties and the geometric parameters of the lattice structure is explored through finite element simulation;This new zero-Poisson's ratio lattice structure can still maintain stable elastic equivalent performance under the condition of large deformation.Using the theory of viscoelastic mechanics,the material's relaxation experiment results were fitted with viscoelastic parameters to obtain the material's viscoelastic properties.The shape memory process simulation and result analysis of the new zero-Poisson's ratio lattice structure based on carbon short fiber reinforced polylactic acid were carried out to investigate the change of Poisson's ratio performance before and after the lattice structure deformation.