| Fiber reinforced composites,due to their characteristics of low density,high performance,easy manufacturing and flexible designability,has become one of the key new materials to replace the traditional metals and realize the purpose of lightweight.Fiber reinforced composites are made of reinforced fiber bonded by toughening resin matrix.Among them,environmentally friendly and widely sourced basalt fiber has been investigated and used as the reinforced fiber in the preparation of fiber reinforced composites,becoming one of the most important strategic materials in the future.Considering that the traditional fiber reinforced composites have an imperfect structure design scheme,which lead to a limited improvement of mechanical performance,their use will be limited in many challenging and difficult working environments in the future.Therefore,it is urgent to make full use of the designability of fiber reinforced composites and introduce new structural design schemes to support the development of a new generation of fiber reinforced composites.As we all know,the creatures have evolved a perfect biological structure in harmony with the living environment gradually,after billions of years of "natural selection,survival of the fittest".Based on this,bionics is proposed,which is to design and prepare bio-inspired materials with excellent properties creatively,by observing the biological morphologies,establishing bio-inspired models and utilizing the mapping relationship between biological structure and properties.Bio-inspired design concept has been proved to be efficient and feasible in designing new materials.Herein,inspired by the perfect unity of biological structure and performance,several bio-inspired composites with excellent mechanical properties were designed and manufactured by basalt fiber reinforced composites,including the mantis shrimp's dactyl club structure with equal helicoidal arrangement in the periodic region,sinusoidal shape in the impact region and the mantis shrimp's telson structure with variable thickness helicoidal arrangement,which are formed to improve impact resistance;lobster shell structure with both helicoidal arrangement and channel sandwich which is evolved to enhance the attack force.The mechanical properties of bio-inspired composites,including impact resistance and flexural resistance,were analyzed and discussed by means of finite element simulation and experiments.The main contents were as follows.(1)Inspired by the equal helicoidal structure in periodic region of mantis shrimp's dactyl club with excellent mechanical properties,four bio-inspired equal helicoidal laminated composites with different helicoidal angles were prepared with basalt fiber/epoxy resin composites,including 12.8°/ one period(UTBFRP/12.8°),25.7°/ two periods(UTBFRP/25.7°),45°/ three periods(UTBFRP/45°)and 90°/ orthogonality(UTBFRP/90)°,to discuss the effect of helicoidal angle and periodic number on mechanical properties in equal helicoidal laminated design.The best impact performance and flexural stability appeared in the composites with the helicoidal angle of 25.7°.Therefore,the mechanical properties of fiber reinforced composites could be improved effectively by mantis-shrimp-inspired equal helicoidal laminated composite.(2)Based on the equal helicoidal structure,inspired by the sinusoidal structure in impact region of mantis shrimp's dactyl club with excellent mechanical properties,the sinusoidal structure in impact region of mantis shrimp's dactyl club was introduced into the design of the equal helicoidal laminate composite and a bio-inspired equal helicoidal-sinusoidal laminated composite was designed and manufactured with basalt fiber/modified cyanate resin composites.Low-velocity impact and three-point flexural tests were carried out on the bio-inspired composites.It was found that the bio-inspired composites inherited the function of inducing crack deflection and prolongating crack path from the equal helicoidal structure.In addition,the sinusoidal structure improved the flexural resistance by changing the load path.Further to observe and analyze the failure morphologies,asymmetrical and serrated cracks distribution were presented obviously.Therefore,the mantis-shrimp-inspired equal helicoidal-sinusoidal laminated composite improved the flexural resistance significantly.(3)Based on the equal helicoidal-sinusoidal structure,inspired by the variable helicoidal structure of mantis shrimp's telson with excellent mechanical properties,a bio-inspired variable helicoidal-sinusoidal laminated composite was manufactured with basalt fiber/expoy resin composites by optimizing the equal helicoidal structure,to further improve the impact resistance of fiber reinforced composites.The peak impact force of bio-inspired variable helicoidal laminated composite was increased by 0.5%compared with UTBFRP/25.7°,which had the best performance among bio-inspired equal helicoidal laminated composites.The fact benefited from the different crack propagation paths in different helicoidal periods which caused by the different helicoidal angles.Moreover,the bio-inspired variable helicoidal-sinusoidal laminated composite inherited the excellent flexural performance of sinusoidal structure.Therefore,the bio-inspired variable helicoidal-sinusoidal laminated composite not only maintained the flexural resistance,but also optimized the impact resistance.(4)Based on the variable helicoidal-sinusoidal structure,inspired by the channel sandwich structure of lobster shell with excellent mechanical properties,a mantisshrimp-inspired variable helicoidal-sinusoidal combined with lobster-inspired channel sandwich composite with basalt fiber/expoy resin composites and aluminum foam core was designed and manufactured.Specifically,the mantis-shrimp-inspired variable helicoidal-sinusoidal laminated composite worked as the top face and the traditional laminated composite with orthogonal arrangement acted as the bottom face.In terms of mechanical properties,the impact resistance of the bio-inspired composite was improved through the variable helicoidal structure and the channel sandwich structure to induce crack deflection,and the peak load was 6012.1 N at the impact energy of 40 J.The deformation energy absorption of the sinusoidal structure and the channel sandwich structure made the flexural absorption energy reached 41.91 k N·mm,which improved the flexural resistance.Here,inspired by biological structure,several bio-inspired basalt fiber reinforced composites were designed and prepared based on the special structures of periodic region and impact region in mantis shrimp's dactyl club,mantis shrimp's telson and lobster shell.As a result,the bio-inspired composites had the similar structures to the original creatures,while inheriting the corresponding excellent performances.This work revealed the mapping relationships between structures and performances,providing a new design concept and technical support for the research and development of new lightweight and high-strength materials in the future. |
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