Achieving high strength,deformability and toughness in polymers is important for practical industrial applications.This has remained challenging because of the mutually opposing effects of improvements to each of thes...Achieving high strength,deformability and toughness in polymers is important for practical industrial applications.This has remained challenging because of the mutually opposing effects of improvements to each of these properties.Here,a self-assembling nacre-like polymer composite is designed to achieve ex-tremely tough with increasing strength.This special design significantly improved polymer’s mechanical properties,including an ultra-high fracture strain of 1180%,a tensile strength of 55.4 MPa and a toughness of 506.9 MJ/m^(3),which far exceed the highest values previously reported for polymer composites.This ex-cellent combination of properties can be attributed to a novel toughening mechanism,achieved by the synergy of the domain-limiting effect of metallic glass fragments with the strain-gradient-induced orien-tation and crystallisation within the polymer during stretching.Our approach opens a promising avenue for designing robust polymer materials in armour and aerospace engineering for a range of innovative applications.展开更多
Morphing technology is one of the most effective methods to improve the flight efficiency of aircraft.Traditional control surfaces based morphing method is mature and widely used on current civil and military aircraft...Morphing technology is one of the most effective methods to improve the flight efficiency of aircraft.Traditional control surfaces based morphing method is mature and widely used on current civil and military aircraft,but insufficiently effective for the entire flight envelope.Recent research on morphing wing still faces the challenge that the skin material for morphing should be both deformable and stiff.In this study,a continuous morphing trailing-edge wing with a new multi-stable nano skin material fabricated using surface mechanical attrition treatment technology was proposed and designed.Computational fluid dynamics simulation was used to study the aerodynamic performance of the continuous morphing trailing-edge wing.Results show that the lift coefficient increases with the increase of deflection angle and so does the lift-drag ratio at a small angle of attack.More importantly,compared with the wing using flaps,the continuous morphing trailing-edge wing can reduce drag during the morphing process and its overall aerodynamic performance is improved at a large angle of attack range.Flow field analysis reveals that the continuous morphing method can delay flow separation in some situations.展开更多
基金This work was financially supported by the Shenzhen-Hong Kong Science and Technology Innovation Cooperation Zone Shen-zhen Park Project(No.HZQB-KCZYB-2020030)the RGC Gen-eral Research Fund(No.AoE/M-402/20,CityU 11209918)+1 种基金the RGC Theme-based Research Scheme(No.T13-402/17-N)the Ma-jor Program of Changsha Science and Technology Project(No.kh2003023).
文摘Achieving high strength,deformability and toughness in polymers is important for practical industrial applications.This has remained challenging because of the mutually opposing effects of improvements to each of these properties.Here,a self-assembling nacre-like polymer composite is designed to achieve ex-tremely tough with increasing strength.This special design significantly improved polymer’s mechanical properties,including an ultra-high fracture strain of 1180%,a tensile strength of 55.4 MPa and a toughness of 506.9 MJ/m^(3),which far exceed the highest values previously reported for polymer composites.This ex-cellent combination of properties can be attributed to a novel toughening mechanism,achieved by the synergy of the domain-limiting effect of metallic glass fragments with the strain-gradient-induced orien-tation and crystallisation within the polymer during stretching.Our approach opens a promising avenue for designing robust polymer materials in armour and aerospace engineering for a range of innovative applications.
基金This work is supported by the Major Program of National Natural Science Foundation of China(No.:NSFC51590892)the Shenzhen Municipal Science and Technology Innovation Commission of China(No.:JCYJ20160229165310679).
文摘Morphing technology is one of the most effective methods to improve the flight efficiency of aircraft.Traditional control surfaces based morphing method is mature and widely used on current civil and military aircraft,but insufficiently effective for the entire flight envelope.Recent research on morphing wing still faces the challenge that the skin material for morphing should be both deformable and stiff.In this study,a continuous morphing trailing-edge wing with a new multi-stable nano skin material fabricated using surface mechanical attrition treatment technology was proposed and designed.Computational fluid dynamics simulation was used to study the aerodynamic performance of the continuous morphing trailing-edge wing.Results show that the lift coefficient increases with the increase of deflection angle and so does the lift-drag ratio at a small angle of attack.More importantly,compared with the wing using flaps,the continuous morphing trailing-edge wing can reduce drag during the morphing process and its overall aerodynamic performance is improved at a large angle of attack range.Flow field analysis reveals that the continuous morphing method can delay flow separation in some situations.
