The multi-layer cylindrical helicoidal fiber structure(MCHFS)exists widely in biological materials such as bone and wood at the microscale.MCHFSs typically function as reinforcing elements to enhance the toughness of ...The multi-layer cylindrical helicoidal fiber structure(MCHFS)exists widely in biological materials such as bone and wood at the microscale.MCHFSs typically function as reinforcing elements to enhance the toughness of materials.In this study,we establish a shear lag-based pullout model of the cylindrical helicoidal fiber(CHF)for investigating interlayer stress transfer and debonding behaviors,with implications regarding the underlying toughening mechanism of MCHFS.Based on the shear lag assumptions,analytical solutions for the stress and displacement fields of the MCHFS during the pullout are derived by considering the CHF as a cylindrically monoclinic material and verified through the 3D finite element simulation.It is found that the helical winding of CHF results in both axial and hoop interlayer shear stresses.Both the helical winding angle and the elastic moduli of the fiber and matrix have significant influences on interlayer stress transfer.This work reveals a new interlayer stress transfer mechanism in the MCHFS existing widely in biological materials.展开更多
Hydrovoltaic power generators that convert water-nanomaterial interactions into electricity represent a promising route for sustainable energy harvesting.However,most previous studies have relied on non-stretchable pl...Hydrovoltaic power generators that convert water-nanomaterial interactions into electricity represent a promising route for sustainable energy harvesting.However,most previous studies have relied on non-stretchable planar designs,requiring continuous water flow or ionic solutions.Here,we present a fully stretchable hydrovoltaic cell(FSHC)with a parallel double-helix configuration of neat and oxidized carbon nanotube(CNT)fibers wound around an elastomeric core.This winding-locked double-helix architecture ensures mechanical robustness and stable electrical properties under strain.When immersed in quiescent deionized water,the FSHC generates~0.31 V and~22.4µA/cm^(2),maintaining reliable performance up to 200%strain.To demonstrate its potential in wearable applications,the FSHC is integrated into a fabric glove.Moreover,multiple FSHCs connected in series or parallel provide sufficient power to drive a twisted CNT fiber actuator.This study introduces a deformable hydrovoltaic platform for fiber-based energy harvesters,broadening their applicability to wearable electronics and self-powered actuation.展开更多
This paper deals with the concurrent multi-scale optimization design of frame structure composed of glass or carbon fiber reinforced polymer laminates. In the composite frame structure, the fiber winding angle at the ...This paper deals with the concurrent multi-scale optimization design of frame structure composed of glass or carbon fiber reinforced polymer laminates. In the composite frame structure, the fiber winding angle at the micro-material scale and the geometrical parameter of components of the frame in the macro-structural scale are introduced as the independent variables on the two geometrical scales. Considering manufacturing requirements, discrete fiber winding angles are specified for the micro design variable. The improved Heaviside penalization discrete material optimization interpolation scheme has been applied to achieve the discrete optimization design of the fiber winding angle. An optimization model based on the minimum structural compliance and the specified fiber material volume constraint has been established. The sensitivity information about the two geometrical scales design variables are also deduced considering the characteristics of discrete fiber winding angles. The optimization results of the fiber winding angle or the macro structural topology on the two single geometrical scales, together with the concurrent two-scale optimization, is separately studied and compared in the paper. Numerical examples in the paper show that the concurrent multi-scale optimization can further explore the coupling effect between the macro-structure and micro-material of the composite to achieve an ultralight design of the composite frame structure. The novel two geometrical scales optimization model provides a new opportunity for the design of composite structure in aerospace and other industries.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.12020101001,12021002,12372324,and 12272239)supported by the National Innovation and Entrepreneurship Training Program for College Students(No.202210056136).
文摘The multi-layer cylindrical helicoidal fiber structure(MCHFS)exists widely in biological materials such as bone and wood at the microscale.MCHFSs typically function as reinforcing elements to enhance the toughness of materials.In this study,we establish a shear lag-based pullout model of the cylindrical helicoidal fiber(CHF)for investigating interlayer stress transfer and debonding behaviors,with implications regarding the underlying toughening mechanism of MCHFS.Based on the shear lag assumptions,analytical solutions for the stress and displacement fields of the MCHFS during the pullout are derived by considering the CHF as a cylindrically monoclinic material and verified through the 3D finite element simulation.It is found that the helical winding of CHF results in both axial and hoop interlayer shear stresses.Both the helical winding angle and the elastic moduli of the fiber and matrix have significant influences on interlayer stress transfer.This work reveals a new interlayer stress transfer mechanism in the MCHFS existing widely in biological materials.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(No.NRF-RS-2021-NR060086,No.RS-2023-00240008,and No.RS-2025-00560512)the Industrial Technology Innovation Program(Alchemist Project)(RS-2025-02634714)funded by the Ministry of Trade,Industry&Energy(MOTIE),Koreathe Institute of Information&communications Technology Planning&Evaluation(IITP)grant funded by the Korea government(MSIT)(No.RS-2025-02263277).
文摘Hydrovoltaic power generators that convert water-nanomaterial interactions into electricity represent a promising route for sustainable energy harvesting.However,most previous studies have relied on non-stretchable planar designs,requiring continuous water flow or ionic solutions.Here,we present a fully stretchable hydrovoltaic cell(FSHC)with a parallel double-helix configuration of neat and oxidized carbon nanotube(CNT)fibers wound around an elastomeric core.This winding-locked double-helix architecture ensures mechanical robustness and stable electrical properties under strain.When immersed in quiescent deionized water,the FSHC generates~0.31 V and~22.4µA/cm^(2),maintaining reliable performance up to 200%strain.To demonstrate its potential in wearable applications,the FSHC is integrated into a fabric glove.Moreover,multiple FSHCs connected in series or parallel provide sufficient power to drive a twisted CNT fiber actuator.This study introduces a deformable hydrovoltaic platform for fiber-based energy harvesters,broadening their applicability to wearable electronics and self-powered actuation.
基金financial support for this research was provided by the Program (Grants 11372060, 91216201) of the National Natural Science Foundation of ChinaProgram (LJQ2015026 ) for Excellent Talents at Colleges and Universities in Liaoning Province+3 种基金the Major National Science and Technology Project (2011ZX02403-002)111 project (B14013)Fundamental Research Funds for the Central Universities (DUT14LK30)the China Scholarship Fund
文摘This paper deals with the concurrent multi-scale optimization design of frame structure composed of glass or carbon fiber reinforced polymer laminates. In the composite frame structure, the fiber winding angle at the micro-material scale and the geometrical parameter of components of the frame in the macro-structural scale are introduced as the independent variables on the two geometrical scales. Considering manufacturing requirements, discrete fiber winding angles are specified for the micro design variable. The improved Heaviside penalization discrete material optimization interpolation scheme has been applied to achieve the discrete optimization design of the fiber winding angle. An optimization model based on the minimum structural compliance and the specified fiber material volume constraint has been established. The sensitivity information about the two geometrical scales design variables are also deduced considering the characteristics of discrete fiber winding angles. The optimization results of the fiber winding angle or the macro structural topology on the two single geometrical scales, together with the concurrent two-scale optimization, is separately studied and compared in the paper. Numerical examples in the paper show that the concurrent multi-scale optimization can further explore the coupling effect between the macro-structure and micro-material of the composite to achieve an ultralight design of the composite frame structure. The novel two geometrical scales optimization model provides a new opportunity for the design of composite structure in aerospace and other industries.
