# Scaled Model Simulation and Experimental Verification of Submarine Flexible Pipeline Laying System
## 3 Similarity Verification of Experimental Scaled Model
### Dynamic Similarity Simulation Verification of Scaled Model
#### 3.2.3 Similarity Verification of Dynamic Characteristics in Angle Adjustment Mechanism Adjustment  
When the flexible pipeline-laying tower system is ready to lay pipes, the angle adjusting mechanism will extend upwards, pushing the entire laying tower to be adjusted slowly from the 50\({}^{\circ}\) tilt state when it is not working to the 90\({}^{\circ}\) vertical state when it is working. During this process, the equipment loaded on the tower, such as tensioners, curvature  
Figure 11: Stress comparison between the lower support part of tensioner support and the hinge of the hydraulic cylinder.  
Figure 12: Stress at the hinge of the tower and lower support part of tensioner support.  
adjusting pulleys, pulley groups on the top of the tower, will be adjusted from the tilt state to the vertical working state with the tower.  
According to Figures 13 and 14, it can be seen that the force at the articulation point of the tower and deck will fluctuate and increase as the tower goes from inclined state to vertical state. When the tower is vertical, the force at this point reaches a maximum value. The force at the articulated joint of the tower and the angle adjustment mechanism decreases gradually with the adjustment of the tower angle. At the initial position of the tower adjustment, the force of the angle adjustment mechanism is the largest. Therefore, the scale model is basically consistent with the original stress at these two places.  
From Figure 15, it can be seen that the force at this point decreases first and then increases when the tower is vertical while the tower is adjusted from 50\({}^{\circ}\) tilt to 90\({}^{\circ}\) vertical. According to Figure 16, the upper connecting rod of the tensioner support has the greatest force at the beginning of the adjustment of the tower. It is also known from the 3D model that the upper connecting rod is under vertical tension and bears most of the load of the tensioner's dead weight; then, with the position of the tensioner adjusted, the tension of the upper connecting rod decreases. However, the tension on the supporting parts under the tensioner support decreases first and then increases gradually to the maximum load.  
Figure 14: Comparisons of forces at articulated joints of tower and angle adjustment mechanism.  
Figure 13: Comparison of forces at articulated points of tower and deck.  
By comparing the force condition of the relative joints of the tower scale model with that of the prototype after similar transformation, it can be seen that the force variation of the scale model and the prototype at the articulated joints of the tower is similar when the pipeline is laid, the tensioner support is raised, and the angle of the tower is adjusted, but the force fluctuation in the prototype is slightly larger, and these fluctuations are within a small range. In general, under the similar criteria deduced above, the scaled model and the prototype satisfy the dynamic similarity.