Fast Analytical Algorithm for Fatigue Crack Life Estimations of Integrally Stiffened Metallic Panels

Abstract:

This work presents the enhancement of a pseudo-numerical tool for fatigue crack growth investigations on integrally stiffened metallic panels. The model is based on an analytical approach that demands compatibility of displacement between skin sheet and stiffener. Since the basis model was presented before, the focus of the present work is on the incorporation of residual stress effects in order to improve simulation results of welded panel configurations that are manufactured by laser beam welding or friction stir welding and exhibit a significant amount of residual stresses. The necessary input parameters for the developed residual stress module are determined from experimental residual stress field measurements. Simulation results using the presented approach are compared with results from finite element simulations on a two stringer panel which show the good accordance of the base model as well as the capability of the tool enhancements to account for the crack retarding effect caused by residual stresses.

• Periodical: Key Engineering Materials (Volumes 385-387)
• Pages: 529-532
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.385-387.529
• Online since: July 2008
• Authors: Sascha Marc Häusler, Peter Horst
• Keywords: Fatigue Crack Propagation, Integral Structure, Residual Stress

References

[1] T. Swift. Damage tolerance analysis of redundant structures. In Fracture Mechanics Design Methodology, AGARD-LS-97, (1979).

[2] T. Nishimura. Stress intensity factors for a cracked stiffened sheet with cracked stiffeners. Journal of Engineering Materials and Technology, 113: 119-124, (1991).

DOI: 10.1115/1.2903366

[3] S. M. Häusler, A. D. Reim, and P. Horst. Fatigue crack growth - a challenge for new integrally stiffened aircraft structures. In Proceedings of the 24th ICAF Symposium, Naples, (2007).

[4] H. Terada and T. Nakajima. Analysis of stress intensity factor of a crack approaching welding bead. International Journal of Fracture, 27: 83-90, (1985).

DOI: 10.1007/bf00040387

[5] H. Tada and P.C. Paris. The stress intensity factor for a crack perpendicular to the welding bead. International Journal of Fracture, 21: 279-284, (1983).

DOI: 10.1007/bf00942346

[6] P. J. Davis and I. Polonsky. Handbook of mathematical functions, chapter 25, page 890. Dover Publications, Inc., New York, (1965).