# Design and Simulation Analysis of a New Type of Assembled UHPC Collision Avoidance
## 3 Performance Analysis of Design Parameters
### Performance Analysis of UHPC Tank Wall Reinforcement Ratio Parameters  
Different reinforcement ratios of the collision avoidance device UHPC box wall are simulated numerically. Considering the actual engineering needs, this research mainly includes four conditions: Condition C1: p = 4%, Condition C2: p = 5%, Condition C3: p = 6%, and Condition C4: p = 7%. The differences due to the reinforcement ratio are mainly reflected in the strength and flexible deformation of the collision avoidance float box. The time-history curves of the bow collision depth under different reinforcement ratios are shown in Figure 25. The changes in the bow collision depth curves under the four conditions are approximately the same. The maximum depth of the bow collision is reached in a short period of time after the impact initiation, and then there is a small rebound. The maximum impact depth of the bow increases with the increase of the reinforcement ratio; however, this is a gradual phenomenon: the maximum impact depths of the bow are 1.47 m and 1.49 m when the reinforcement ratio is 6% and 7%, respectively, and the maximum impact depth of the bow is relatively small (1.21 m) when the reinforcement ratio is 4% and 5%. This shows that the reinforcement ratio of the UHPC box wall is better for the ship protection when reinforcement ratio is 4% and 5%. The energy curves of the collision avoidance device under the four conditions are shown in Figure 26. The trends of the collision avoidance device energy curves under the four conditions are similar, reaching their peak values at approximately 1.6 s, then decreasing slightly and tending to stabilize at approximately 2.2 s. This is due to the elastic deformation and energy absorption of the collision avoidance device during the initial stage of the impact and some elastic deformation that occurs after the impact. When the reinforcement ratio is 5%, the maximum absorbed energy of the collision avoidance device is 26.3 MJ, and the plastic deformation energy is 24.6 MJ after stabilization. The difference between them is 1.7 MJ, which is only approximately 6.9% of the plastic deformation energy of the device. It can be seen that the main absorbed energy of the collision avoidance device is the plastic deformation of the device. When the reinforcement ratio is 6%, the deformation absorption  
Figure 24: Collision avoidance performance of the device under different wall thickness. Figure 25: Bow impact depth time-history curve. of the collision avoidance device is mainly caused by the plastic deformation of the device. The plastic deformation energy is 15.87 MJ after stabilization. In Figure 27, the time-history curves of the impact force under the four working conditions are given. It can be seen in this figure that the peak values of the impact force under Conditions C1, C2 and C3 are obviously smaller than those under Condition C4. At the same time, the peak values of the impact force under these three conditions are 27.5%, 31.6%, and 30.9%, respectively. A double-layer and two-way reinforcement arrangement can directly affect the overall strength of the collision avoidance floating box. When the reinforcement ratio is 7%, the rigidity of the floating box is the largest, and a larger rigid body displacement occurs in the initial stage of the impact. The peak value of the impact force directly impacting the pier is the largest, reaching 30.73 MN, which does not take full advantage of the plastic energy absorption. Therefore, the device cannot absorb energy during the collision process. The ship kinetic energy is the smallest. At the same time, when the reinforcement ratio is 5%, the peak value of the impact force on pier is the smallest, which is 24.13 MN, and the impact duration, which is 2.60 s, is the longest. This is substantially consistent with the design concept of a flexible the collision avoidance device.