Mechanical Properties Of Origami Structures Considering Engineering Materials And Non-zero Thickness

Origami structures have the characteristics of variable shape,adjustable stiffness and excellent energy absorption.Therefore,they have been gradually applied into the fields of buckling-restrained brace,vehicle and ship protection,flexible electronics,intelligent instruments and structures.However,there are still some fundamental scientific problems such as difficult design of origami crease,disharmony between non-zero thickness configuration and folding performance,strong coupling between material and mechanical properties.Origami creases considering engineering materials and non-zero thickness have become one of the key points of engineering origami research for their wider engineering applications.Therefore,origami structures can be deformed reasonably along the predetermined creases and exhibit excellent mechanical properties.Based on the previous research,this paper takes engineering materials and the design of crease with non-zero thickness as the point of penetration.From a single crease element to complex origami structures,the mechanical properties of structure are evaluated through stress deformation,buckling mode,energy dissipation and fatigue properties.The main research works are as follows:(1)Considering the non-zero thickness of engineering origami,10 crease elements are proposed and designed.The entire folding process is simulated and analyzed by finite element software ABAQUS.The crease composed of three rows of oblong holes exhibits excellent mechanical properties by comparing the force,the moment,deformation characteristics,energy absorption characteristics,etc.Ensuring enough rigidity,it has a stable stress process and small peak force with no obvious stress concentration phenomenon in the process of cyclic folding and expansion.Moreover,it has a better energy absorption characteristic.(2)Based on the optimized crease,the effects of parameters(thickness t,hole width w,hole length l,hole spacing b and row spacing d)on its mechanical properties is studied which provides an important reference for the engineering design and application.The results show that t,b and d are larger,l and w are smaller,the initial stiffness is greater,the greater the force,the fuller the bending moment-angle lag curve,and the smaller the residual deformation.In addition to d,t,b and d are larger,l and w are smaller,the specific energy absorption of the crease will be larger,and the stronger the energy consumption capacity.(3)Considering engineering material properties,the morphological evolution of three rows of long round hole crease is analyzed during the folding process.When the required origami structure has high rigidity and good energy absorption,mild steel,stainless steel,Q235 and Q345 can be satisfied.When the structure needs to have a better deformation energy absorption under the premise of less force,brass and aluminum should be used.If the economic benefits are considered,the aluminum material is preferred.It can make origami structures have a more ideal energy absorption capacity while reducing the initial peak load.(4)Based on the crease design considering non-zero thickness and engineering materials,three rows of oblong hole creases are applied to origami structures.To explore their buckling deformation characteristics during folding,Rhino and Grasshopper are used for parametric design and modeling for origami structures(Kresling symmetrical/antisymmetrical origami tubes,Diamond origami tubes,Yoshimura origami tubes,Miura-ori metamaterials and Rotorigami protective structures).Compared with the corresponding non-perforated origami structures,the stress concentration phenomenon is greatly reduced because of the redistributed internal force.The panel is induced to be reasonably deformed along the fold.Under the premise of the energy effect,the initial peak load and peak load are greatly reduced.In this case,the structure can be deformed and absorb energy in advance under a smaller buckling load.Therefore,the above origami structure can be applied to vehicle and ship protection devices,intelligent mechanical anti-collision devices and buckling-restrained brace.(5)Based on theory of fatigue,the simulation of ABAQUS and FE-SAFE is used to predict the fatigue life of the origami structures.Therefore,the Manson-Coffin formula is used to calculate the theoretical fatigue life.The influence of five basic parameters is evaluated on its fatigue performance.Except for thickness t,the effects of other parameters of the crease element are nonlinear on the fatigue performance.Moreover,we explore the influence of different engineering materials on the fatigue performance.The crease using aluminum not only make the structure less stressed,but also have a long fatigue life.Finally,the effects of crease openings are explored on the fatigue performance for non-zero thickness origami structure.Compared with the origami structures without holes,the fatigue life of origami structures with openings is increased by at least 2.5 times.Therefore,crease openings can effectively improve the fatigue life of origami structures.