That the rapid increasing calculation amount caused by large calculation domain has limited the parachute dropping numerical researches. To solve this problem, the traditional fixed Euler meshes were replaced by moving Lagrange meshes to describe the flow field, and then the parachute dropping process was calculated by FSI (Fluid Structure Interaction) method in this paper. A typical plane parachute was taken as the research object. The flow field surrounding the parachute-payload system was defined as the calculation domain firstly. Both the flow field and structure field were discretized by finite elements. The moving velocity of fluid meshes was calculated according to the displacement of the payload in global coordinates. In other words, the graphical deformation principle was applied to realize the computational domain followed the parachute-payload system. Then the calculation of parachute opening process was carried on in this finite space by FSI method. At last, the abundant flow field and structure field information and the deceleration characteristics curves such as velocity and acceleration were obtained by this method. In order to verify the accuracy of this method, the deceleration characteristics results were compared with experimental results. The moving meshes method could decrease the calculation amount and provide abundant results information. The method used in this paper also could provide a reference for other inflatable fabrics numerical researches.

To investigate the fundamental melt spinning behavior of the islands-in-the-sea (S/I) fibers,bicomponent melt spinning of polystyrene (PS) and polypropylene (PP) with the composition of 1 : 1 was performed using a spinning pack for preparation of S/I fibers with 1519 islands in the fiber cross-section. The sheath-core (S/C) fibers and blend fibers of the same composition were also prepared for comparison. The reduction ratio of the cross-sectional area of polymer flow from the position of the confluence of two polymer flows to the die exit for the sheath-core type spinning pack is 16 : 1, whereas that for the islands-in-the-sea type spinning pack is 3200 : 1. In this research, particular attention was paid to the behavior of polymer flow in the vicinity of spinneret. Magnitude of die-swell decreased with the increase of extrusion temperature. It was also found that the swelling was more significant for the S/I spin-line in comparison with that for the S/C spin-line. When the S/C and S/I components were exchanged from PS/PP to PP/PS, the swelling behavior of S/C spinline decreased whereas that of S/I spin-line did not show any significant change. On the other hand, magnitude of die-swell for the blend spinning was larger than that for the S/I and S/C spinnings and increased with the increase of extrusion temperature. The distance from the spinneret surface to the position of maximum spinline diameter increased in the order of S/C<S/I<blend. These results suggested that the swelling effect in the S/C and S/I spinning is governed by the viscoelastic effect whereas that in the blend spinning is caused mainly by the interfacial tension between the two components.

Lignin functions as an effective reinforcing filler for natural rubber (NR), when it was mixed with NR latex by the soft processing method. The lignin was aggregated, but localized around rubber particles in the NR latex to form a network-like structure of lignin in the NR matrix after drying. The observation clearly showed the role of filler networks for the excellent reinforcement of rubber in the case of organic filler similarly to inorganic fillers.