The former studies indicate that loading rates significantly affect dynamic behavior of brittle materials, for instance, the dynamic compressive and tensile strength increase with loading rates. However, there still are many unknown or partially unknown aspects. For example, whether loading rates have effect on crack dynamic propagating behavior (propagation toughness, velocity and arrest, etc). To further explore the effect of loading rates on crack dynamic responses, a large-size single-cleavage trapezoidal open (SCTO) specimen was proposed, and impacting tests using the SCTO specimen under drop plate impact were conducted. Crack propagation gauges (CPGs) were employed in measuring impact loads, crack propagation time and velocities. In order to verify the testing result, the corresponding numerical model was established using explicit dynamic software AUTODYN, and the simulation result is basically consistent with the experimental results. The ABAQUS software was used to calculate the dynamic SIFs. The universal function was calculated by fractal method. The experimental-numerical method was employed in determining initiation toughness and propagation toughness. The results indicate that crack propagating velocities, dynamic fracture toughness and energy release rates increase with loading rates; crack delayed initiation time decreases with loading rates.

以前的研究表明，加载速率会显着影响脆性材料的动力学行为，例如，动态抗压强度和拉伸强度会随加载速率的增加而增加。但是，仍然存在许多未知或部分未知的方面。例如，加载速率是否对裂纹的动态扩展行为（扩展韧性，速度和阻滞等）有影响。为了进一步探讨加载速率对裂纹动力响应的影响，提出了一种大型单裂口梯形开放式（SCTO）试样，并进行了在跌落板冲击下使用SCTO试样的冲击试验。裂纹扩展计（CPG）用于测量冲击载荷，裂纹扩展时间和速度。为了验证测试结果，利用显式动态软件AUTODYN建立了相应的数值模型，仿真结果与实验结果基本吻合。ABAQUS软件用于计算动态SIF。通用函数通过分形方法计算。实验数值方法用于确定起始韧性和传播韧性。结果表明，裂纹扩展速度，动态断裂韧度和能量释放率均随加载速率的增加而增加。裂纹的延迟启动时间随加载速率而降低。实验数值方法用于确定起始韧性和传播韧性。结果表明，裂纹扩展速度，动态断裂韧度和能量释放率均随加载速率的增加而增加。裂纹的延迟启动时间随加载速率而降低。实验数值方法用于确定起始韧性和传播韧性。结果表明，裂纹扩展速度，动态断裂韧度和能量释放率均随加载速率的增加而增加。裂纹的延迟启动时间随加载速率而降低。