FATIGUE ANALYSIS OF ALUMINUM BOX-STIFFENER LAP JOINTS BY NOMINAL, STRUCTURAL AND NOTCH STRESS RANGE APPROACHES

This paper systematically investigates the fatigue behavior of an aluminum box-stiffener lap joint. Fatigue analysis, based on nominal stress range approach, and two local approaches based on structural (hot spot) as well as notch stress are applied respectively. The structural stress range approach depends on how the structural stress concentration factors (SCFs) are obtained by means of several stress extrapolation methods. Different stress extrapolation methods are also discussed. Stress analysis is performed by the finite element (FE) method. Twelve full-scale specimens are included in the test program. The results show that the notch stress range approach is the most conservative one among the three approaches. However, the nominal stress range approach gives the least conservative approach to the joint.