Research On Compressive Mechanical Properties Of Curved Origami Tube Structures

The unique geometric topology configuration of origami tube structure endows it with superior mechanical properties,such as large specific stiffness and strength,which has huge application potential in mechanical engineering,aerospace,architectural engineering and other fields.Origami tubes form different types of geometric configurations by folding along creases and space through two-dimensional planes.Although origami tube structure has shown advantages such as light weight and ultra conventional mechanical properties,most of the current research is linear crease tube structure.Because there is only one straight crease between two points,the design freedom of the structure of the paper folding tube is greatly reduced,and then the mechanical properties of the paper folding tube are limited.However,countless curve creases can be designed between two points,thus forming countless curve crease folding tube structures,which broadens the design freedom of folding tube structures and greatly enriches the design of folding tube structures with better mechanical properties.Therefore,in this paper,curve creases are introduced into two-dimensional crease expansion diagram,and explicit functions are used to quantify the shape of curve creases.After space folding,a curved paper folding tube structure is designed,and the compression mechanical properties of curved paper folding tube structure are systematically studied by experiment,simulation and parameter analysis.The main research work is as follows:(1)By introducing and quantifying curve creases to two-dimensional crease patterns,a novel curved origami tube structure is designed.The basic unit of two-dimensional plane structure is composed of two curve valleys and one curve mountain.Curve creases are characterized by six parameters w₁,w₂,w,h,r₁,r₂and quadratic functions.The linear and curved-crease folding tubes were designed,and the finite element simulation technology was used to compare the compression mechanical properties of linear and curved-crease folding structures,which proved that curved-crease structures had higher design freedom and richer mechanical properties.In order to accurately characterize the material constitutive model in finite element calculation,a curved paper folding tube structure sample was prepared by metal3D printing technology,and the mechanical properties of the material were tested by standard tensile test.In addition,to probe into the metal surface of the preparation of 3D printing paper folding the manufacturing precision of sample tube structure,with high precision three-dimensional CT scanning technique reconstruct the 3D model of curved surface origami tube samples,and the quantitative analysis of the internal error,bubble size and porosity,with in-depth analysis of curved pipe compression mechanical properties of paper and reveal the physical mechanism behind it.(2)Based on numerical simulation and experimental methods,the quasi-static axial compression mechanical properties of curved origami tubes were studied.Firstly,the supercomputing platform is used to carry out parallel computation of the quasi-static axial quasi-static compression process of curved paper folding tube,and the sensitivity analysis of the grid is carried out to determine the mesh size that compromises the computational accuracy and computational efficiency.Secondly,the quasi-static compression mechanical properties of curved paper folding tube were studied by universal material drawing machine,and compared with the finite element simulation results in the aspects of deformation mode and mechanical response,it is found that:a)the finite element simulation can accurately simulate the quasi-static compression process of curved paper folding tube;B)The curved paper folding tube shows compression and torsion characteristics during compression;C)Curved paper folding tube has good mechanical properties.Combined with CT scan results,the reason why the mechanical response obtained by the experimental method is lower than that obtained by finite element analysis is illustrated.(3)Based on the verified high-precision finite element simulation model,the influence of key design parameters on the compressive mechanical properties of curved paper folding tubes was further studied.The influence of the important geometric parameters of curved paper folding tube,such as curve valley w₁,curve mountain w₂,boundary w and thickness t,on the mechanical properties of curved paper folding tube was explored,and it was found that:When w₁is small and w₂is large,the deformation mode is"overall torsion"?"panel bending"(overall compression and torsion characteristics),while when w₁is large and w₂is small,the deformation mode changes to"upper part torsion"?"upper part panel bending"?"lower part torsion"?"lower part panel bending"(partial compression and torsion characteristics).Therefore,simply changing the curve mountain and curve valley of the basic unit can achieve a wide range of control of the overall compressive mechanical response of curved paper folding tube structure and good mechanical properties.