SEDL / STP / STP833-EB / STP32548S

Analysis and Growth of Cracks in Skins with Variable Thickness

Ratwani, MM
Manager and Engineering Specialist, Structural Life Assurance Research, Northrop Corporation, Aircraft Division, Hawthorne, Calif.

Kan, HP
Manager and Engineering Specialist, Structural Life Assurance Research, Northrop Corporation, Aircraft Division, Hawthorne, Calif.

Pages: 13    Published: Jan 1984

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Abstract

Analysis of cracks in skins with variable thickness (skins with lands) was developed. The problem was reduced to the solution of an integral equation by using the Fourier transform technique. The integral equation was solved numerically and stress intensity factors were obtained. The influence of variable skin thickness ratios on stress intensity factors was investigated.

An experimental program was carried out to obtain crack growth data in skins with variable thickness (skins with lands). The crack growth behavior in those skins was predicted using analytical stress intensity factors and a crack growth model. A good correlation between predicted and observed crack growth behavior under constant amplitude as well as spectrum loading was found.