Deformation And Mechanical Behavior Of Torsional Energy Absorbing Structures Constructed By Folding Creases

For the past few decades,scientists have been developing metamaterials,a kind of artificial composite material with properties that natural materials don’t have,and whose properties are determined by their design structure rather than their chemical composition.And mechanical metamaterials have attracted extensive attention from scientists because of their unique mechanical properties that traditional materials do not have.Their unique and novel properties are closely related to their own structures.Through designing and preparing different structures,materials can have many unique mechanical properties.Origami structures have received wide attention in the past few years,due to the excellent mechanical properties of origami structures,some scholars have designed mechanical metamaterials inspired by origami structures.Different from the traditional origami design method using facets,A new chiral metamaterial truss structure is constructed by using the creases in the origami structure,and as a device to absorb energy through torsional deformation.The main contents of the paper are as follows:Firstly,a new chiral mechanical metamaterial truss structure was constructed by replacing the creases of the origami structure with trusses inspired by triangular cylinder origami.The parametric modeling of the truss structure was completed by using three-dimensional drawing software SOLIDWORKS,the basic geometric analysis of the structure is carried out,and the analytical model of the structure is established by using MATHEMATICA.The motion process of the structure was calculated by using energy method,and then the model was imported into ANSYS for finite element analysis to simulate the motion state of the structure under the action of load.Secondly,3D printing was carried out on the modeled truss structure,nylon FS 3300PA was used as the material,and experiments were carried out on the 3D printed samples.Experimental data and video were recorded during the experiment,and the video in the compression experiment was imported into MATLAB for binarization processing.The Angle of rotation of the sample during compression is calculated using the white paper attached to the sample.By comparing the theoretical values calculated in MATHEMATICA,the simulated values in ANSYS and the experimental values,the consistency of the three results is verified,which proves that finite element simulation can effectively predict the mechanical properties of truss structures.The control rules of initial height₀h,truss edge number n,radius r and initial Angleθ₀ on torsional deformation and mechanical response of the mechanical metamaterial structure are further studied.Finally,in order to further strengthen the energy absorption characteristics of the structure,the contact and non-contact friction energy absorption devices were designed on the basis of the double-layer truss structure,which combined the deformation energy absorption of the structure itself and the friction energy absorption between adjacent structures.Under the action of load,the mechanical response value and energy absorption value are larger.The energy absorption device was modeled with SOLIDWORKS and imported into ANSYS for finite element simulation.The simulation results were compared with the results of the 3D printed energy absorption device experiment,and the energy absorption effect of the two devices was explored.On the other hand,the programmable letter pattern is constructed by using the rotating characteristic of double truss structure.Results show that the structural torsion angle can be increased by increasing the height or decreasing the radius of the truss structure.The Young’s modulus of the structure can be increased by decreasing the height,increasing the initial angle or increasing the side number of truss structure.Negative stiffness can be introduced by decreasing the height and the initial angle or increasing the radius of the truss structure and the side number of truss structure.Reducing the height,initial angle,radius of truss or increasing the side number can increase the value of energy absorption.The mechanical properties of the structure can be significantly adjusted by changing the geometric parameters,which has good programmable design.The proposed mechanical metamaterial structures are expected to be applied in the fields of aerospace,mechanical engineering,automobile manufacturing and so on.