## 5 Simulation Analysis of Traction Dynamics of the Space Flexible Web
### Analysis of the Traditional Rope Web Unfolding Process  
In the traditional rope web launching and deployment simulation model, the shape of the mesh body adopts a hexagonal structure of the same size as the new space flexible web; The hexagonal length is 2.5 m, the grid element is a conventional quadrilateral element, the unit is 0.4167 m \(\times\) 0.4167 m, and the web rope is a circular cross-sectional flexible rope with a diameter of \(\phi\)10(mm), as shown in the figure in Figure 2 above. The flexible web rope is launched and pulled by six pullers, which are reduced to six cylinders with a diameter of 0.1 m and a height of 0.2 m on the bottom. Because of the dynamic characteristics of sizeable nonlinear deformation of the mesh rope, the flexible mesh rope is set by LINK167-unit, considering that among the many element types such as BEAM, SHELL, and SOLID, the LINK167 unit [18] is similar to the spring-unit and is only subjected to axial tension. Improper selection of the unit type will lead to incorrect solution results. The initial model is the complete unfolded state of the figure in Figure 2 above, and then the initial unfolded state is changed to the specified receiving state by speed control. Because the folding process of the web rope is complicated and the web attitude of the receiving state is difficult to be characterized, we therefore simulate the receiving state of the actual web rope before launching, employing an instantaneous receiving attitude of the flexural rope movement under speed control, and then export the element information and nodal information of the model through the output command in LS-PREPOST processing, modify the K information of the initial fully extended model, and reset the initial emitting velocity to conduct a simulation. The model processing is shown in Figure 8 below. After the model processing, 22,976 NODE messages were generated from the traditional rope web model in the receiving state. Gravity was set along the Z-axis, and air resistance was achieved by damping. These are considering that this chapter focuses on the simulation process of the traditional rope web, topological rope web, and a new type of space flexible web flying along the Z-axis, comparing and analyzing the dynamic characteristics of the new type of space flexible web. Therefore, the Z-direction launch initial velocity of six tractors is set to 50 m/s in line with the actual speed, and the X-direction and Y-direction are set separately according to the different positions of the six tractors, each tractor body's X- and Y-direction combined speed is 50 m/s so that the object can be formed in the air for a short period. The simulation run time can be taken into account in the study of the traditional roping deployment process. In the finite element model of Figure 8 above, the traction body is set to rigid body PART, and the web rope is set to flexible body PART. The connection between the two is defined by the keyword \"CONSTRAINED_EXTRA_NODESD. The parameters of the simulation material for the flexible web rope and the traction body are set out in Tables 2 and 3 below:  
Figure 8: Process of traditional rope web simulation model. Due to the significant flexible deformation problem, the solution time of the model is long, and the non-convergence is easy to occur. After solving the problem, the simulation process of projectile deployment of conventional symmetric structure flexible mesh rope is shown in Figure 8 below. Figure 9a-h represent eight typical instantaneous poses during the unfolding of the rope net. It was observed that the rope web experienced about 0.12 s from the folding and receiving state to the expansion and forming of the rope to the maximum area. According to the above traditional rope web ejecting process, mainly around the axial force of the rope web, rope deformation, and traction body (and web rope) of the movement of the analysis is shown in Figure 10 below, and diagrams a to f depict the forces on the webbing at six instantaneous moments.