## 3 Results
### Spatiotemporal Evolution Characteristics of Acoustic Emission Parameters  
Under different loading rate conditions, the variation curves of acoustic emission ring-down counts over time for samples were plotted based on the acoustic emission data obtained from the experiment, aiming to analyze the evolution characteristics of acoustic emission ring-down counts of samples. Due to the significant difference in the order of magnitude of acoustic emission ring-down counts before and at the moment of sample failure, the analysis was divided into two stages for precise examination, as shown in Figure 6.  
Figure 6a,b reveal that at a 0.1 kN/s loading rate, acoustic emission counts are mostly under 100, evenly distributed until a surge to 352 just before failure and peaking at 7023 counts at failure, averaging 443 counts/s. According to Figure 6c,d, at a loading rate of 0.5 kN/s, before the peak load, the acoustic emission ring-down counts during the loading process show a slow increasing trend over time, mostly below 200 counts, with a higher value of 886 counts appearing close to sample failure, and the highest value of 10,839 counts at the moment of failure, followed by several weaker ring-down counts, with an overall average level of approximately 3259 counts/s. According to Figure 6e,f, at a loading rate of 1.0 kN/s, before the peak load, the acoustic emission ring-down counts during the loading process exhibit a rapid increasing trend over time, generally below 400 counts, with a higher value of 502 counts appearing close to sample failure, and two higher values of 15,057 and 16,207 counts at the moment of failure, followed by fewer ring-down counts, with an overall average level of approximately 9336 counts/s. According to Figure 6g,h, at a loading rate of 5.0 kN/s, before the peak load, the acoustic emission ring-down counts during the loading process exhibit an exponential rapid increasing trend over time, with ring-down counts mainly concentrated just before sample failure and with high values, reaching up to 1547 counts, with several higher values appearing at the moment of failure, up to 13,718 counts, followed by several weaker ring-down counts, with an overall average level of approximately 15,046 counts/s. To analyze the evolution characteristics of the acoustic emission energy of samples under different loading rate conditions, variation curves of acoustic emission energy over time for samples under different loading rates were plotted based on the acoustic emission data. Given the significant difference in the magnitude of acoustic emission energy before and at the moment of sample failure, the analysis was also divided into two stages for precise examination, as shown in Figure 7.  
Figure 5: The fitting relationship between tensile strength and tensile stress change rate. Figure 6: Evolution characteristics of acoustic emission ringing count under different loading rates. Figure 7: Evolution characteristics of acoustic emission energy under different loading rates. Figure 7a,b indicate that at a 0.1 kN/s loading rate, acoustic emission energy remains low, under 100 ms\(\cdot\)mV, before peaking at 5333 ms\(\cdot\)mV upon failure, averaging 122 ms\(\cdot\)mV/s. In Figure 7c,d, with a 0.5 kN/s rate, energy ranges up to 250 ms\(\cdot\)mV before reaching a maximum of 20,533 ms\(\cdot\)mV at failure, with an average of 1224 ms\(\cdot\)mV/s. Figure 7e,f show that at 1.0 kN/s, energy levels are below 300 ms\(\cdot\)mV until spiking to 25,808 ms\(\cdot\)mV at failure, averaging 3493 ms\(\cdot\)mV/s. Lastly, Figure 7g,h at 5.0 kN/s show energy levels up to 350 ms\(\cdot\)mV before a peak of 29,242 ms\(\cdot\)mV at failure, with an average of 9166 ms\(\cdot\)mV/s, illustrating a significant increase in acoustic emission energy as loading rates rise.