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根据应力强度因子和断裂韧性的定义,研究并分析了应力强度因子的影响因素;表明试件的几何尺寸和物质材料的应力强度水平对应力强度因子起着决定性因素。辨明了起裂韧性、断裂韧性和止裂韧性的区别与联系;针对断裂K准则,提出了动态断裂韧性测试中的失稳判据,即dσ/dt=0,得到了试件所受的最大载荷对应于裂纹的失稳判据;并通过SHPB冲击装置,对这个失稳判据进行了验证。发现在8.0×10~4到35×10~4MPa·m~(1/2)s~(-1)的加载速率范围内,试验所用玄武岩的动态断裂韧性随着加载速率的增大而增大的规律。
According to the definition of stress intensity factor and fracture toughness, the influencing factors of stress intensity factor are studied and analyzed. It is shown that the stress intensity factor of specimen geometry and material stress plays a decisive role. The difference and relationship between the fracture toughness, the fracture toughness and the fracture toughness were discerned. According to the fracture K criterion, the instability criterion in the dynamic fracture toughness test was put forward, that is, dσ / dt = 0. The maximum The load corresponds to the instability criterion of crack. Through the SHPB impact device, this instability criterion is verified. It is found that the dynamic fracture toughness of basalt used in the experiment increases with the increase of loading rate in the loading rate range of 8.0 × 10 ~ 4 to 35 × 10 ~ 4MPa · m ~ (1/2) s ~ (-1) The law.