## 3 Results
### Energy Characteristic Analysis  
The relationship between impact toughness and strain rate of PCCY and ACCY test pieces is shown in the Figure 7. The following conclusions can be drawn: the impact toughness of the PCCY test piece group and the ACCY test piece group is closely related to strain rate and impact velocity, and the addition of aluminum oxide fiber also changes the impact toughness of the test piece. An exception to this is that the impact toughness of the 1 ACCY test piece decreases slightly under a high strain rate and impact velocity; for example, at 98.87 s\({}^{-1}\) and 8.99 m/s, it decreased from 1784.7 kJ/m\({}^{3}\) to 1711.2 kJ/m\({}^{3}\) at 114.79 s\({}^{-1}\) and 10.09 m/s, respectively. Other test groups showed that the strain rate level changed from low to high, and the impact toughness was significantly improved. In order to better understand the relationship between dynamic elastic modulus and strain rate, the relationship between strain rate and dynamic elastic modulus of specimens in the PCCY and ACCY test groups is linearly fitted. See Formula (3) for specific treatment results. Under a similar strain rate and impact velocity, an appropriate amount of aluminum oxide fiber gives the concrete matrix additional impact toughness. The overall impact toughness is composed of two parts: the toughness provided by aluminum oxide fiber and the toughness provided by the concrete matrix. Aluminum oxide fiber is used to replace the concrete matrix in an appropriate amount, so that the fiber is pulled from the concrete matrix by external force during the impact process, and part of the toughness provided by the concrete matrix is replaced in this process. For example, the impact toughness of the 2 ACCY test group is better than that of the PCCY test group. From the fitting data, it can be found that adding an appropriate amount of aluminum oxide fiber improves the growth rate of impact toughness. In Formula (3), the slope of 2 PCCY is higher than that of other test groups. The impact of aluminum oxide fiber with higher content on impact toughness is basically consistent with the situation of high content in the strength characteristics section of this paper. \[\left\{ \begin{array}{ll}\text{PCCY}:&IT=-502.11+18.659\tilde{\overline{e}}&(R ^{2}=0.9956)\\ 1\text{ACCY}:&IT=-464.38+20.154\tilde{\overline{e}}&(R^{2}=0.7816)\\ 2\text{ACCY}:&IT=-732.63+23.872\tilde{\overline{e}}&(R^{2}=0.9286)\\ 3\text{ACCY}:&IT=-500.01+18.528\tilde{\overline{e}}&(R^{2}=0.9712)\\ 4\text{ACCY}:&IT=-531.92+18.339\tilde{\overline{e}}&(R^{2}=0.8929)\\ 5\text{ACCY}:&IT=-694.13+18.854\tilde{\overline{e}}&(R^{2}=0.9015)\\ \end{array} \right. \tag{4}\]  
### Energy Characteristic Analysis  
The peak strain of each group of specimens is the abscissa value, corresponding to the highest point in the stress-strain curve. It is the strain at the beginning of failure after the specimen exceeds the critical value of the linear stage in the process of impact compression. If the applied impact compression load is suddenly unloaded at this time, the specimen cannot return to the original linear change shape, and the maximum compressive effect is expressed to the outside world. It can be seen from the figure that when the strain rate of each component group is lower than 95 s\({}^{-1}\) and the impact speed is less than 9 m/s, the peak strain increases with the increase in strain rate and impact speed. When the strain rate is higher than 95 s\({}^{-1}\) and the impact speed is greater than 9 m/s, the group of 3 ACCY, 4 ACCY, and 5 ACCY still follows the above increasing law. The peak strain of the PCCY, 1 ACCY, and 2 ACCY specimen groups shows test values different from the above law. Although the overall trend is increasing, the peak strain in individual test groups shows variation. In order to analyze the relationship between peak strain and strain rate, they are linearly fitted, and the fitting condition is poor, R\({}^{2}\) values are lower than 0.5, and the solid is omitted.