Research On Low-velocity Impact Resistance Of Biomimetic Spiral Composite Structure Based On 3D Printing

The biomaterial-inspired composites can adjust the mechanical properties of the structure through the strategy of exploiting advantages and avoiding disadvantages,such as the damage tolerance and impact resistance of the structure.The results show that the microstructure of a variety of excellent biomaterials is that the uniaxial nanofiber layer is arranged into a spiral shape periodically,which is characterized by light weight,high strength and significant impact resistance and damage tolerance.However,how to optimize the structure of this biomimetic spiral composite structure to achieve its maximum impact resistance has not been studied.Inspired by the microstructure of this biomimetic spiral composite structure,a circular plate model with 6,8 and 10 layers of 0°,15°,30°,45°,60°,75° and 90° was designed in this paper.In this paper,the 3D printing molding technology of the model was first studied,and the bionic spiral structure model was prepared after the off-line printing method,printing temperature,printing layer thickness,printing speed and other optimal printing technological parameters were obtained.Then using deflection low-speed impact testing machine to carry out the dynamic impact test at low speed,the Angle of different layer thickness and layer structure of the low speed impact resistance,the influence of the test results show that as the Angle of layer and the change of the layers(thickness),the structure of the low speed impact resistance can be improved accordingly,the thicker the layer thickness,the smaller the spiral Angle of layer(except 0 °),the better the performance of structure impact resistant,and vice versa;In order to verify the test and make up the deficiency of the test,the numerical simulation of the impact of isotropic circular plate is also carried out by using LS-DYNA software.The numerical simulation results show that the thicker the layer,the stronger the impact resistance of the structure.With the change of impact velocity,the structural response and failure process also change greatly.With the increase of impact velocity,the structure gradually develops from crack propagation failure to penetration failure.Through analysis and research,the reason why the impact resistance of the structure can be improved by improving the rotation Angle of the layer is that while giving full play to the tensile strength of the monolayer material,rotating the layer can effectively avoid the structural failure occurring in the weakness of the monolayer material,that is,the anisotropy of the structure can be effectively improved.This in order to enhance the protection performance of important engineering structures provides a more convenient method of improving with the maturity of concrete 3 d printing technology,expect to apply this kind of spiral printing layer structure during the construction of concrete structure,in order to improve the impact resistance of concrete structure,resistance to penetration ability,at the same time also can achieve economic and rapid construction,application prospect.