Development and Evaluation of Methods of Plane Stress Fracture Analysis. Part III. Application of the Residual Strength Prediction Technique to Complex Aircraft Structure.

摘要

Using the residual strength technique, uniaxially loaded, angle stiffened wing panels were analyzed and fracture strengths determined. Excellent correlation was obtained between experimental and analytical data for an initially intact and broken central stringer for a six bay aluminum panel with thin skin, a thick (0.193 inch) skin aluminum panel, and an all titanium panel. Both crack arrest and fracture could be predicted using the tangency conditions between the crack driving force curves (sq.rt. of (J) and the crack growth resistance curve (sq.rt. of J sub R). The influence of biaxial load ratio (tension fields) on crack opening displacement, plastic zone size and load transfer was examined for an all aluminum fuselage panel with a crack in the skin located normal to the longerons and parallel to the frames. Comparisons are made between analytical and experimental strain and residual strength data for biaxially loaded structure.