STRESS INTENSITY FACTORS FOR A CRACKED STIFFENED SHEET WITH CRACKED STIFFENERS

The stress intensity factors are calculated for a cracked sheet and cracked stiffeners attached with rivets. The approach adopted is based on compatibility of displacements among the sheet, fasteners, and stiffeners. Displacements in the cracked stiffener are determined by adding the induced displacements from cracks to intact stiffener displacements, which are obtained using empirical stress intensity equations. In addition, displacements in the cracked sheet are calculated using the basic solution of a single stiffener for analyzing any combinations of stiffener (either intact, broken, or cracked). Bending flexibilities of the sheet and stiffeners are ignored, and the analysis is conducted within the limitations of elasticity theory. The proposed method is verified by comparing it to numerically computed results from finite element analysis.