飞机结构中,有些并非关键危险结构,即当它断裂时不会立即使飞机发生灾难性破坏;但由于它的断裂,在继续使用时会引起关键危险部位(结构)断裂,从而产生灾难性事故。通常称这类结构的断裂故障为潜在危险性故障。因此,统计估算这类结构的裂纹扩展寿命对设计和使用维护都有实际意义。以往的统计,常常不严格区分所获得的数据是结构尚未断裂还是结构已经断裂,甚至全部当成完全的裂纹扩展寿命(即到检查时刻为止的飞行时间就是 Some of the aircraft structures are not critical structures, that is, they do not immediately cause disastrous damage to the aircraft when it breaks; however, due to its failure, the critical parts of the structure (structures) are fractured when it continues to be used, resulting in a catastrophic accident . Fracture faults of this type are often referred to as potentially dangerous faults. Therefore, statistical estimation of the crack propagation life of such structures is of practical significance for the design and maintenance. In the past statistics, the data obtained often did not make a strict distinction between whether the structure has been broken or the structure has been broken, or even all the cracks have a complete life span (that is, the flight time up to the inspection time is