MULTIPLESITE CORROSION DAMAGE ASSESSMENT

In order to quantitatively assess the residual strength ofthe aging aircraft with widespread corrosion damages the equivalent cracksize technique is used to simulate the surface corrosion pits asinitial surface cracks on corrosion structure, where ahypothetical initial surface crack with the same life as thecorrosion pit is used. Thus the analysis of the corrosion structure withnumerous pits becomes a problem of multiple surface cracks. Then, the parameterfinite element method and the cycle-by-cycle iterative algorithm areused to compute thestress intensity factor, crack extension directions, and crack-growthincrements. When the stress intensity factor history is obtained using thecrack-growth increment and stress intensity factors, the fatigue life of thestructure under fatigue loading is estimated through cycle-by-cycle damageaccumulation. The result provides a guidance for fatigue lifeprediction of an aircraft structure with widespread corrosion pits incomplicated environments.