A non-stretchable fiber rotation in planar flows has been solved. The fiber will rotate periodically or run to the asymptotical direction decided by a discriminant defined in the paper involving the fiber aspect ratio...A non-stretchable fiber rotation in planar flows has been solved. The fiber will rotate periodically or run to the asymptotical direction decided by a discriminant defined in the paper involving the fiber aspect ratio and the flow characteristics. Subsequently the fiber orientation distribution is derived directly without the bother of solving the Fokker-Planck equation. The research clearly indicates the overall configuration of a fiber rotation movement in planar flows.展开更多
Engineered cementitious composites(ECC),also known as bendable concrete,were developed based on engineering the interactions between fibers and cementitious matrix.The orientation of fibers,in this regard,is one of th...Engineered cementitious composites(ECC),also known as bendable concrete,were developed based on engineering the interactions between fibers and cementitious matrix.The orientation of fibers,in this regard,is one of the major factors influencing the ductile behavior of this material.In this study,fiber orientation distributions in ECC beams influenced by different casting techniques are evaluated via numerical modeling of the casting process.Two casting directions and two casting positions of the funnel outlet with beam specimens are modeled using a particle-based smoothed particle hydrodynamics(SPH)method.In this SPH approach,fresh mortar and fiber are discretized by separated mortar and fiber particles,which smoothly interact in the computational domain of SPH.The movement of fiber particles is monitored during the casting simulation.Then,the fiber orientations at different sections of specimens are determined after the fresh ECC stops flowing in the formwork.The simulation results show a significant impact of the casting direction on fiber orientation distributions along the longitudinal wall of beams,which eventually influence the flexural strength of beams.In addition,casting positions show negligible influences on the orientation distribution of fibers in the short ECC beam,except under the pouring position.展开更多
The algorithm for evaluation of fiber orientation distribution function (ODF) by laser scattering method based on 2 - dimentional model of fiber arrangement and the method of determining diffuse scattering intensity a...The algorithm for evaluation of fiber orientation distribution function (ODF) by laser scattering method based on 2 - dimentional model of fiber arrangement and the method of determining diffuse scattering intensity are presented. The fiber ODFs of nonwoven samples measured by the computer-program-controlled laser scattering intensity testing system are compared with that of the data obtained by microprojector method. The results show that the algorithm is feasible for assessing the fiber ODFs of nonwoven fabrics manufactured by different processing methods.展开更多
基金Project (No. 10632070) supported by the Major Program of theNational Natural Science Foundation of China
文摘A non-stretchable fiber rotation in planar flows has been solved. The fiber will rotate periodically or run to the asymptotical direction decided by a discriminant defined in the paper involving the fiber aspect ratio and the flow characteristics. Subsequently the fiber orientation distribution is derived directly without the bother of solving the Fokker-Planck equation. The research clearly indicates the overall configuration of a fiber rotation movement in planar flows.
基金This work belongs to the project No.T2021-97TD in 2021 funded by Ho Chi Minh City University of Technology and Education,Vietnam.
文摘Engineered cementitious composites(ECC),also known as bendable concrete,were developed based on engineering the interactions between fibers and cementitious matrix.The orientation of fibers,in this regard,is one of the major factors influencing the ductile behavior of this material.In this study,fiber orientation distributions in ECC beams influenced by different casting techniques are evaluated via numerical modeling of the casting process.Two casting directions and two casting positions of the funnel outlet with beam specimens are modeled using a particle-based smoothed particle hydrodynamics(SPH)method.In this SPH approach,fresh mortar and fiber are discretized by separated mortar and fiber particles,which smoothly interact in the computational domain of SPH.The movement of fiber particles is monitored during the casting simulation.Then,the fiber orientations at different sections of specimens are determined after the fresh ECC stops flowing in the formwork.The simulation results show a significant impact of the casting direction on fiber orientation distributions along the longitudinal wall of beams,which eventually influence the flexural strength of beams.In addition,casting positions show negligible influences on the orientation distribution of fibers in the short ECC beam,except under the pouring position.
基金This project is supported by Key Subject Foundation of Shanghai Educational Committee.
文摘The algorithm for evaluation of fiber orientation distribution function (ODF) by laser scattering method based on 2 - dimentional model of fiber arrangement and the method of determining diffuse scattering intensity are presented. The fiber ODFs of nonwoven samples measured by the computer-program-controlled laser scattering intensity testing system are compared with that of the data obtained by microprojector method. The results show that the algorithm is feasible for assessing the fiber ODFs of nonwoven fabrics manufactured by different processing methods.
