Based on the flow simulation in the condensing zone of compact spinning with lattice apron and a bead-elastic rod dynamic model of the flexible fiber,trajectories of fibers with different negative pressure are simulat...Based on the flow simulation in the condensing zone of compact spinning with lattice apron and a bead-elastic rod dynamic model of the flexible fiber,trajectories of fibers with different negative pressure are simulated by specially designed Matlab procedure.Then displacement components of fibers at YZ profile under different negative pressure conditions are extracted and compared.The results show that the fibers of different initial positions gradually converge,and are interlaced for position change in yarn cross-section,caused by the airflow in the condensing zone.Finally,compact-spun yarn with different negative pressure and conventional ring spun yarn are produced and their twists are tested.Both the results of simulation and experiments illustrate the existence of additional twists.Also the relationship between additional twists and negative pressure is verified.展开更多
Compact spinning with pneumatic grooves is a spinning process to gather fibers by blended actions of airflow and mechanical forces.Modified from the ring spinning system,the lateral compact spinning with pneumatic gro...Compact spinning with pneumatic grooves is a spinning process to gather fibers by blended actions of airflow and mechanical forces.Modified from the ring spinning system,the lateral compact spinning with pneumatic grooves can improve yarn appearance and properties due to generated additional twists.In this study,we investigated additional twists of the lateral compact spinning with pneumatic grooves via a finite element(FE)method.An elastic thin rod was used to model a fiber to simulate its dynamic deformation in the three-dimensional space,and the space bar unit was used to simplify the fiber model for the dynamic analysis.The stiffness equation of the elastic rod element and the dynamic equation of the rigid body mass element were derived from the differential equation of the elastic thin rod.In the analysis of the nonlinear geometric displacement of the space elastic thin rod unit,the large deformation problem was solved with the stepwise loading successive approximation.The simulation results explained the mechanism of generating additional twists,and the experiment results proved the existence of additional twists.The study demonstrated that the FE model is effective for predicting additional twists of fiber bundles in the agglomeration zone,and for simulating the fiber motion in the compact spinning with pneumatic grooves.展开更多
The technological process of compact spinning and the compact procedure of fiber band in compact field are briefly illustrated. The motions of fiber band in compact field are discussed theoretically from which tilting...The technological process of compact spinning and the compact procedure of fiber band in compact field are briefly illustrated. The motions of fiber band in compact field are discussed theoretically from which tilting angle of suction slot in profile tube, additional twists created by fiber band’s rotating around its own axis and ultimate twists in compact yarn are deduced accordingly. The existence of additional twists is also verified through experiments.展开更多
文摘Based on the flow simulation in the condensing zone of compact spinning with lattice apron and a bead-elastic rod dynamic model of the flexible fiber,trajectories of fibers with different negative pressure are simulated by specially designed Matlab procedure.Then displacement components of fibers at YZ profile under different negative pressure conditions are extracted and compared.The results show that the fibers of different initial positions gradually converge,and are interlaced for position change in yarn cross-section,caused by the airflow in the condensing zone.Finally,compact-spun yarn with different negative pressure and conventional ring spun yarn are produced and their twists are tested.Both the results of simulation and experiments illustrate the existence of additional twists.Also the relationship between additional twists and negative pressure is verified.
基金This work is supported in part by China Scholarship Council and National Key R&D Program of China(Grant No.2017YFB0309100).
文摘Compact spinning with pneumatic grooves is a spinning process to gather fibers by blended actions of airflow and mechanical forces.Modified from the ring spinning system,the lateral compact spinning with pneumatic grooves can improve yarn appearance and properties due to generated additional twists.In this study,we investigated additional twists of the lateral compact spinning with pneumatic grooves via a finite element(FE)method.An elastic thin rod was used to model a fiber to simulate its dynamic deformation in the three-dimensional space,and the space bar unit was used to simplify the fiber model for the dynamic analysis.The stiffness equation of the elastic rod element and the dynamic equation of the rigid body mass element were derived from the differential equation of the elastic thin rod.In the analysis of the nonlinear geometric displacement of the space elastic thin rod unit,the large deformation problem was solved with the stepwise loading successive approximation.The simulation results explained the mechanism of generating additional twists,and the experiment results proved the existence of additional twists.The study demonstrated that the FE model is effective for predicting additional twists of fiber bundles in the agglomeration zone,and for simulating the fiber motion in the compact spinning with pneumatic grooves.
基金Sponsored by Shanghai Rising Star Program, No .02QF14005
文摘The technological process of compact spinning and the compact procedure of fiber band in compact field are briefly illustrated. The motions of fiber band in compact field are discussed theoretically from which tilting angle of suction slot in profile tube, additional twists created by fiber band’s rotating around its own axis and ultimate twists in compact yarn are deduced accordingly. The existence of additional twists is also verified through experiments.
