Design And Mechanical Property Analysis Of Novel Chiral Compression-torsion Coupling Metamaterial

Mechanical metamaterial is a focus in current research.In recent years,many new phenomena and physical properties have been discovered.As a kind of mechanical metamaterial,the torsional effect of the compression-torsion coupling metamaterial makes the axial stress state change to the circumferential stress state due to the artificial design of the microstructures.This characteristic attracts more and more scholars' attention.It subverts people's perception of deformation response of materials or structures under load,and it has a bright prospect.However,there are few studies on compression-torsion coupling metamaterials.The design and analysis of structures that can produce torsion effect are imperfect,and the existing research shows that the effect of torsion is small.In this paper,compression-torsion coupling metamaterial will be designed to make its compression-torsion coupling effect better.The reason why the torsion effect of previous studies are small is analyzed.It is found that there are two main factors affecting its torsion: One is that the mutual counteraction of the cells themselves,and the other is that the cell joint is too restrictive.At the same time,the elastic constants of a novel twodimensional chiral compression-torsion coupling metamaterial are analyzed with various geometric parameters is also analyzed,and give its change rule.Photosensitive resins were selected as materials to fabricate a novel two-dimensional chiral compressiontorsion coupling metamaterial,and the basic mechanical parameters were measured by experiments.Subsequently,the test equipment was improved to measure the torsion angle accurately,and the test samples with different geometric parameters were tested.The simulated and measured results are in good agreement with each other.It is proved that the experimental equipment used in this paper can measure the torsion angle accurately.By comparison,it is found that the novel two-dimensional chiral compression-torsion coupling metamaterial designed in this paper has a certain increase in torsional effect compared with the previous study.A novel three-dimensional chiral compression-torsion coupled metamaterial is designed based on reducing the constraints at the junction of cells.The geometric model is established and the influence of each geometric parameter on the torsion of the whole structure is analyzed by finite element simulation.The results show that the geometric parameters of the chiral structure parallel to the loading direction have a great influence on the overall performance,and the change of geometric parameters of chiral structures vertical to the loading direction has little effect on the overall performance.Moreover,the novel three-dimensional chiral compression-torsion coupling metamaterial has a certain increase in torsion effect compared with the previous research results.