Buckling And Energy Absorption Of Thin-Walled Origami Tube And Corrugated Tube Subjected To Axial Impacting

The process of collision is essentially an energy transformation. During collision the kinetic energy is transformed into deformation energy and other forms of energy. In the structural crashworthiness design, plastic deformation of the structure should absorb as much of the impact kinetic energy as possible in order to ensure the safety of protected personnel and property. The ideal energy absorption member is that the initial peak force should be as small as possible and fluctuation range is small in order to absorb more energy at the plastic deformation stage. Thin-walled metal structure is a kind of light weight, low cost, easy manufacture and high energy absorption efficiency components, and widely used in engineering as important impact energy absorbing structure.The thin-walled origami tube and corrugated tube are studied in this paper. Introduce the particular pattern on the surface of the square tube and circular tube to promote the structure deformation and collapse according to the pattern. Dynamic responses of thin-walled origami tube and corrugated tube under axial impacting are simulated using finite element software. Buckling modes, deformation mechanism and energy absorption capabilities are systematically studied. The main conclusions are drawn as follows:The thin-walled origami tube with pre-designed different fold angles based on the square tube is obtained. The geometric fold angle equation of the origami tube is derived through theoretical analysis. Dynamic buckling and energy absorption of thin-walled origami tubes with six different fold angles under axial impacting are simulated using finite element software LS-DYNA, and compared with the square tube. Numerical results show that deformation modes of origami tube can be classified into three stages, the initial peak stage, the stable progress buckling stage and the densification stage. The initial peak force of origami tube is significantly lower than that of the square tube, and the fluctuation range of the square tube is larger than that of the origami tubes in the stable progress buckling stage. The folding angle is one of important influence factors on the initial peak force and mean force. The pre-designed fold angle demonstrates some obvious advantages at reduce initial peak force and the fluctuation range of impact force curves which are smoother than the square tube. In addition, the specific energy absorption of the origami tubes are lower than the square tube, while the crush force efficiency and specific total efficiency of origami tube with a certain folding angle is higher than the square tube.The thin-walled corrugated tube with pre-designed sinusoidal patterns based on the traditional circular tube is obtained. Dynamic buckling, energy absorption and response process of corrugated tubes with sinusoidal patterns under axial impacting are simulated using LS-DYNA. The effects of buckling and energy absorption are analyzed by change the wavelength, amplitude and radius-thickness ratio. Numerical results show that the initial peak force of corrugated tubes is significantly lower than that of the circular tube. In addition, the bottom contact force of corrugated tube is equal to0before the densification stage and takes advantage of these great properties of corrugated tube which can be used to design protective structures in industry. The deformation modes of corrugated tubes with sinusoidal patterns can be classified into three crushed modes, including dynamic asymptotic buckling, dynamic plastic buckling and transition buckling. The result shows that the main parameters that affect the deformation of corrugated tube consist of impact velocity and radius-thickness ratio. With the increase of radius-thickness ratio or impact velocity, dynamic plastic bulking gradually changed to dynamic asymptotic buckling. Compression distance, initial peak force, specific energy absorption and stroke efficiency of corrugated tube changed with impacting velocity.Finally, dynamic plastic buckling mechanical model is established based on the certain assumptions. The theoretical equation of the impact force ratio and displacement of corrugated tubes is developed. The theoretical results reveal that the deformation of the plastic hinge depends on wavelength, amplitude and the angle of circular segment. When the wavelength is constant value, the deformation increases with the increase of the amplitude, when the amplitude is constant value, the deformation decreases with the increase of the wavelength. The theoretical results exhibit good agreement with the numerical simulation results by changed the amplitude and the wavelength.