복합재 로터 블레이드의 내결함 안전수명 평가

Helicopter rotor systems are dynamically loaded structures with many composite components such as main and tail rotor blades. Fatigue properties of composite materials are extremely important to design durable and reliable helicopter rotor blades. The safe-life methodology has been generally used in the helicopter industry to substantiate dynamically loaded composite components. However, it is not available to evaluate the strength reducing effects of flaws and defects that may occur in manufacturing and operational usage. Damage tolerance methodology provides a proper means to overcome this shortcoming, but it is difficult to economically apply it to every composite components. Flaw tolerant methodology is an equivalent option to damage tolerance for civil and military rotorcraft. The flaw tolerant safe life evaluation is described and illustrated by means of successful application to substantiate the retirement time of composite blades.