Damage Tolerance of Stiffened-Skin Structures: Prediction and Experimental Verification

Some consequences of application of the current damage tolerance airworthiness requirements for transport aircraft in designing stiffened-skin structures to be safe under all operational load conditions are discussed. Compliance with these requirements may be shown by analysis supported by test evidence. To provide the designer with analytical tools to demonstrate that design meets the required residual strength and crack propagation properties a number of computer routines were developed by the NLR. The principles underlying the calculation procedures used in these computer programs to predict the residual strength of stiffened panels with a skin of ductile material (like 2024) are included. Applications of these programs to some practical stiffened skin structures are presented together with analysis test correlations.