对于无规玻璃纤维增强环氧树脂材料切口尖端的破损观察发现,大约在65％的断裂载荷时开始出现破损。破损区随着载荷的增加而增大。与破损区对应的有效裂纹长度用柔度标定技术确定。有预制切口的试件受到恒定载荷作用时,其有效裂纹长度的增量用测量裂纹口部的位移或柔度的变化来确定。文中指出,当应力强度因子到达临界值时,试件就发生断裂。 A breakage observation of the incision tip of a random glass fiber reinforced epoxy material revealed that breakage began to occur at about a 65% breaking load. Damaged area increases with load. The effective crack length corresponding to the damaged area is determined by the flexibility calibration technique. When a specimen with a preformed incision is subjected to a constant load, the increment of its effective crack length is determined by measuring the change in displacement or flexibility of the crater. The paper points out that when the stress intensity factor reaches the critical value, the specimen breaks.