V–22 AIRFRAME FATIGUE TEST METHODOLOGY AND SPECTRUM DEVELOPMENT

The unique capabilities of the V–22 that allow it to operate both as an airplane and a rotary-wing aircraft present significant challenges in both its design and qualification process. This paper addresses the approach used to develop the basic fatigue test methodology and loading spectrum used to qualify the V–22 airframe. The integration of both fixed-wing and rotary-wing fatigue test requirements and their evolution into a cohesive overall test methodology and approach for the V–22 are discussed. This discussion includes the fatigue loads development for specific control zones. It also addresses the analytical fatigue damage assessment performed for fatigue sensitive control points throughout the airframe.