SEDL / STP / STP945-EB / STP23275S

Fatigue Crack Growth at Root Radii in Sheets with Variable Thickness

Ratwani, MM
Manager, Structures Research, senior technical specialist, Specimen Preparation and Mechanical Test, M and P Research and Technology, Northrop Corporation, Aircraft Division, Hawthorne, CA

Kan, H-P
Manager, Structures Research, senior technical specialist, Specimen Preparation and Mechanical Test, M and P Research and Technology, Northrop Corporation, Aircraft Division, Hawthorne, CA

Hsu, SM
Manager, Structures Research, senior technical specialist, Specimen Preparation and Mechanical Test, M and P Research and Technology, Northrop Corporation, Aircraft Division, Hawthorne, CA

Pages: 16    Published: Jan 1988

Download this paper for $25 PDF (228K)          View License Agreement
Abstract

Fatigue crack growth data have been obtained for cracks at root radii in sheets with variable thickness. These test data were obtained under constant-amplitude as well as spectrum loading. Analytical stress-intensity factors were developed using mathematical techniques. The Mode I stress-intensity factors were approximately 10% lower than that of a plate with uniform thickness. Crack growth predictions for the test specimens were made using the analytical stress-intensity factors and a crack growth equation for a skin with uniform thickness. A good correlation is shown between observed and predicted crack growth behavior.