Preparation And Properties Of Bionic Fiber Reinforced Composites With High Performance Based On Hedgehog Spines

With the rapid development of the national economy and continuous progress in the engineering field,the demand for the work efficiency of engineering materials is constantly increasing.That is,to maintain the safety and legal standards of the carrying equipment while reducing the weight of equipment components,solve the conflict between the two key characteristics of lightweight materials and excellent mechanical properties,and achieve lightweight and high-strength coordination.At the same time,it is also one of the most critical and core issues of sustainable development,which is of great significance to the environment,energy saving and economic benefits.It is difficult for single metal or alloy such as magnesium,aluminum,titanium and other light metal materials to fully meet its needs because of its high temperature performance is not good,expensive and other shortcomings.The new materials with high performance and multi-functional development trend emerge at the historic moment.The fiber reinforced composite materials with low density fiber and matrix materials have the advantages of integrated design and manufacturing of material,structure and function due to its extremely high specific strength and modulus.It is increasingly applied in aerospace,rail cars,deep sea exploration,civil engineering,sports goods,medical equipment and other industries.Through millions of years of survival,organisms have developed fine-grained micro and nano structures,resulting in bottom-up design strategies at ambient temperatures that often exhibit a unique combination of high performance and lightweight.In order to adapt to the growing environment requirements(light and strong),hedgehogs have evolved spines,epidermal appendages derived from hair that cover the whole back and side of the body to protect the internal soft body,and make the defense mechanism of the skin appendages more perfect and more active.Falling from a height of 8meters at a speed of 15m/s,hedgehog will have a relatively high instantaneous speed when it hits the ground.If there is no effective means to buffer the energy,irreversible damage will be caused to its internal tissues and nerves.However,the single spines densely distributed on the back and side of the body,weighing about4 mg,can protect the internal body intact.The integrity of the hollow fiber structure of spines can be maintained even when subjected to external forces far greater than their own weight.when subjected to external attacks or predation,the spines dissipate energy through large deformation transfer of more than 60%.Spines have superior mechanical properties under limited material utilization,and the performance is far beyond the composition of natural materials,demonstrating the efficient design of nature,and providing a natural template for the research of life science,engineering science,materials science and other fields.Therefore,exploring the internal functional mechanism of hedgehog spines can provide inspiration for the bionic design of a new generation of high-performance materials.In this paper,Erinaceus europaeus spines,adult hedgehog spines were selected as the research object.The key factors affecting the performance of hedgehog spines,such as non-smooth surface morphology,three-dimensional morphology of biological keratin fibers,multi-scale structure,material composition,macro and micro mechanical properties,were studied in depth.The mechanism of light weight and high strength was revealed.The bionic light weight and high strength composite materials were designed and prepared by using three-dimensional fiber braiding technology and fiber surface modification technology taking hedgehog spines as biomimetic prototype.Furthermore,the design and manufacture of the bionic anti-instability three-dimensional braiding composite materials and its performance test were carried out by taking the multi-stage porous structure as the design inspiration.In terms of the mechanism of light weight and high strength of biomaterials:(1)The spines are a kind of composite materials that its modulus decreases gradually from the outside to the inside.This non-uniform distribution can improve mechanical properties by relieving stress concentration.With a hierarchical structure ranging from molecular level to nanometer scale to macro structure,spines are a biofiber reinforced composite with functional gradient.The hierarchical fiber reinforced composite can improve overall strength,flexibility and energy absorption.(2)The spines are hollow porous structures,which are composed of a large number of unidirectional layered fibers.Fiber bridging,dislocation slip and distortion are internal toughening methods of microscopic fibers,which make the toughness of biological structures higher than that of artificial materials.The cracks of spines generated between layers of fibers not propagate in a straight line,but constantly deflect and distort,thus increasing the propagation path of cracks and dissipating a lot of energy.This progressive damage mode can improve the resistance to external forces.(3)The variable cross-section characteristics of spines are not only conducive to picking up food and attacking prey,but also easier to penetrate the matrix,reduce the penetration load and delay buckling.The specific strength of the spines is 0.76N/mg and 0.94N/mg,which is larger than that of the 201 stainless steel rod with the same diameter,which is 0.53N/mg.It is a kind of biomaterials with both toughness and strength.Based on the analysis of the light weight and high strength mechanism of biomaterials,the key elements were further extracted for biomimetic design,and the biomimetic material-structure-function integrated finite element model was constructed and analyzed numerically.Based on 3D visualization model design and optimization,bionic lightweight high-strength fiber reinforced composites were prepared.And the failure mode of bionic composite material is explored.The design and manufacture of the fiber reinforced composite based on the light weight and high strength mechanism of the hedgehog spine can be divided into the following aspects:(1)The key feature of the hedgehog spine is the hollow porous structure,and the corresponding threedimensional model is established.It was determined that the spine structure could raise the critical buckling load and enhance the buckling resistance.A compromise strategy is adopted to prevent buckling: it has the highest critical buckling load under tangential load,while maintaining a high critical buckling load under axial compression.Biomimetic spine structure can be more effective in cushioning impact,having higher material utilization efficiency and better impact resistance.(2)The biomimetic lightweight and high-strength composite materials were prepared by three-dimensional fiber integrated braiding technology,fiber surface modification technology and hand paste molding technology.The bending strength and bending modulus of biomimetic modified three-dimensional braiding composite materials were increased by about 39.8%and 18.8%,respectively,and the compression strength and deformation resistance were increased by about 28.7% and 46.7%,respectively.Compared with the traditional honeycomb structural materials and glass fiber three-dimensional braided composite materials,the biomimetic modified three-dimensional braided composite has higher specific strength,indicating better light and high strength performance.(3)Inspired by spines’ multi-stage porous structure,the bionic anti-instability three-dimensional braided composite materials are designed and manufactured.The specific strength is increased by about 240% respectively.The overall stability and light and high strength performance are further improved.The main innovations of this paper are:(1)By analyzing the key factors affecting performance of hedgehog spines,such as non-smooth surface morphology,bio-keratin fiber three-dimensional morphology,multi-scale structure,material composition,macro and micro mechanical property,the material-structure-function integration model was established.The mechanism of "light and high strength" of hedgehog spines was revealed by utilizing the external rigid and internal flexible material characteristics to achieve stress homogenization.It provides a theoretical basis for the design of bionic fiber reinforced composites under different working conditions and loads.(2)Based on the analysis of mechanical properties,macro and micro structure characteristics,light and high strength mechanism of hedgehog spines,combined with glass fiber surface modification technology,three-dimensional fiber integrated weaving technology and hand coating molding technology,the bionic light and high strength composite material is designed and manufactured,which provides a preliminary exploration for the design and application of a new generation of light and high strength engineering materials.(3)The hierarchical porous structure in the spines was found.When subjected to external forces,the materials around the pore could relax the local stress by utilizing the deformation of the pore space.The mechanism of load transfer and anti-instability of the hierarchical porous structure was revealed,and the corresponding porous foam equivalent structure model was established.To sum up,take hedgehog spine,a typical representative of anti-instability,light weight and high strength properties,as biological prototype,revealing the internal and external toughening mode of hedgehog spines as functional gradient biological fiber reinforced composites.Based on its mechanism,the design and preparation of bionic lightweight high strength three-dimensional braided composite materials are studied.On this basis,inspired by the multi-stage porous structure of spines,a kind of bionic anti-instability,lightweight high-strength composite functional material applied to the key components was developed,and the corresponding research and exploration was carried out for the design and application of new engineering materials.