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In order to analyze the compression and recovery behavior of cotton fiber assembly, and to improve the quality of cotton bales. a cotton fiber assembly model is established based on the modeling idea of three-dimensional braided composite material. At the same time, the compression modulus and recovery modulus of the cotton fiber assembly are measured by experiments. The finite-element analysis of the cotton fiber assembly is carried out with the obtained compression and recovery modulus, the recovery rate and the compression power recovery rate of the cotton fiber assembly are predicted. By further study of the effect of moisture regains on the recovery rate and compression power recovery rate of cotton fiber assembly, a referenced moisture regain value of 8.8% in cotton baling process is given. The results show that the analyzed results are consistent with the actual situation; the model has certain application value. [ABSTRACT FROM AUTHOR]

In order to analyze the mesoscopic contact characteristics of cotton fiber creep, this paper uses the meso-particle discrete element method to establish a cotton fiber assembly creep microscopic model based on the existing cotton fiber creep experiment. The microscopic parameters of the Particle Flow Code contact constitutive model are calibrated according to the macroscopic mechanical indexes of cotton fiber creep obtained from experiments, and the creep strain of the cotton fiber in the instantaneous creep stage under different compressive stresses and the contact force between particles are analyzed. According to the time–temperature equivalence principle, the calculation efficiency of the viscoelastic discrete element model is optimized, which improves the time scale of the simulation test. The results show that the numerical simulation results accord with the variation characteristics of the experimental creep variables, which verifies the feasibility of the method in this paper. The research results can provide a certain reference for the deeper study of cotton fiber creep characteristics and its mechanism. [ABSTRACT FROM AUTHOR]

In order to study the variation of the drafting force of cotton slivers, a three-dimensional model of cotton slivers was proposed. The model is based on the three-dimensional network structure of the fibers in the cotton sliver. The three-dimensional network structure is simulated by an octahedron. Based on the similarity between dynamic drawing and static drawing, the static drawing simulation of the model is carried out by using ANSYS software, and the static drawing force of different quantitative cotton slivers is simulated. The results show that the average relative error of the static stretch force and dynamic drafting force is 8.09%, and the maximum relative error is less than 15%. Then, the equations of the dynamic drafting force and static stretch force are obtained by linear regression, and the drawing force under other quantitative conditions is successfully predicted. Finally, static stretching is used to simulate the influence curve of different roller spacings on the dynamic drafting force, and the results show that the simulation results are consistent with the actual situation. Therefore, the octahedral cotton sliver model is effective, and the simulation results also provide a reference for the approximate prediction of dynamic drafting force. [ABSTRACT FROM AUTHOR]

In order to analyze the stress state of the seed cotton in the process of ginning cotton, a theoretical model for cotton, namely three-dimensional braided cotton was developed. The model consists of cotton fiber bundles arranged according to the unit cell structure of a three-dimensional four-directional braided composite material. The fiber bundle has a circular section and the shape of the cross section remains unchanged along the axial direction. Based on this model, the serrated ginning process is simulated using finite-element analysis. By analyzing of the effects of different moisture regain and speed on the serration cotton ginning process, the results show that the simulation results agree with the actual situation and the model has certain applications. Compared to the laminated cotton model, the three-dimensional braided cotton model has been improved obviously. In terms of model structure, the three-dimensional braided cotton model is closer to the actual situation of cotton than the existing laminated cotton model. The whole model in the laminated cotton model is an entity, which is bonded together by multiple layers of single-layer panels at different angles. The three-dimensional braided cotton model takes into account the intertwining of fibers and apces, but does consider the distribution of cottonseed which will be the focus research. [ABSTRACT FROM AUTHOR]

The principle of cotton fiber creep recovery and stress relaxation based on viscoelasticity was studied. The constitutive model for cotton fiber creep and stress relaxation was established. The creep value and variation of cotton fibers were tested under different compressive load. The results showed that the creep and stress relaxation of cotton fibers represented nonlinear viscoelasticity. The mechanical behaviors like creep recovery and stress relaxation for cotton fibers were well evaluated by nonlinear viscoelasticity model. In the scope of the study, by adding more load, the creep recovery value of cotton fibers was increased and the creep recovery mechanical index was enlarged. As the strain value of cotton fibers increase, the mechanical index of stress relaxation was enlarged. [ABSTRACT FROM AUTHOR]

The process of cotton ginning was simulated by the finite element method in order to improve and optimize the efficiency of the process. Based on the fractal theory, a new cotton model was established by observing the morphological structure of cotton: the fractal cotton model with cotton seed. Considering the existence of seeds in actual cotton, the model assumes that the cotton fiber bundles are distributed in a fractal structure and the section is simplified as a circle. The finite element simulation of the model was carried out using ANSYS Workbench software, and the viscoelastic material parameters of cotton fibers were determined under different moisture content, the effects of different moisture contents and rotation speeds on the saw type gin stand were analyzed, and the stress and strain nephograms of cotton at different times were checked. The simulation results showed that when moisture content was between 6.1% and 7.8%, the ginning efficiency is the highest. The higher the speed of the saw tooth, the more severe the effect of ginning, but too high a speed will also affect the quality of the cotton lint. The results showed that the simulation conclusions were in line with the actual situation, and the model had certain application value. [ABSTRACT FROM AUTHOR]

In order to analyze the compressive stress state of a cotton fiber assembly in the compression process, a new cotton fiber assembly model, the tetrakaidecahedral porous cotton fiber assembly model, is presented based on the idea of three-dimensional open-cell foam material modeling. Based on the model, the compression process of cotton fiber assembly is analyzed using the finite element method. The change in the compressive stress of the cotton fiber assembly in the compression process is successfully described. The measurement method of compressive modulus of the cotton fiber assembly is also studied, and the relation between compressive modulus and relative density of the cotton fiber assembly is determined. Finally, the effect of different moisture regain on compressive stress of the cotton fiber assembly is analyzed, and the reference value of moisture regain in the cotton baling process is given. The results show that the simulation results are consistent with the actual situation. Therefore, the established model of cotton fiber assembly has validity. [ABSTRACT FROM AUTHOR]

To analyze the stress state of seed cotton in the process of cotton ginning and to improve the quality of lint, a new model for cotton, the laminated cotton model, is presented based on the idea of a composite laminate. The model assumes the cotton mass is made up of a certain number of cotton fibers, each of which has a different arrangement angle. Based on this model, the ginning process is simulated using finite element analysis. The mechanical properties of a single cotton fiber that is either machine- or hand-picked are obtained. The working condition of the ginning process is described successfully. By analyzing the influence of different working conditions on the serration cotton ginning process, the simulation results show the model prediction is reasonably consistent with existing experiments. For example, to improve the productivity and quality of lint, it is important to guarantee the saw teeth are sharp and smooth, with none being crooked or inverted, and missing teeth on each saw blade should not exceed the specified value. [ABSTRACT FROM AUTHOR]