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09 June 2020

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Application of the Virtual Crack Closure Technique to Calculate Stress Intensity Factors for Through Cracks with an Elliptical Crack Front

Engineering Fracture Mechanics 59: 327-342

Fawaz, S. A. (1998)

 

Abstract

Fractographic observations on fatigue tested 2024-T3 clad aluminum riveted lap-splice joints indicate oblique fronts after the initial surface or corner crack at a rivet hole has penetrated through the sheet thickness. No stress intensity factor solutions, K s, are available for this geometry subject to remote tension, remote bending and rivet loading, which are typical for a pressurized fuselage of a transport aircraft. To reduce model generation time for each crack geometry, one finite element mesh is modified to create a new mesh for each crack geometry; thus, maintaining an orthogonal crack-front mesh is not possible. The validity of the three-dimensional virtual crack closure technique, 3D VCCT, with nonorthogonal finite element meshes for calculating mode I stress intensity factors is assessed. Comparisons are made to existing two- and three-dimensional K solutions obtained using conformal mapping, boundary collocation and finite element analysis. Parametric investigations on the influence of rivet load distribution revealed different effects on K for small and large cracks. Using the 3D VCCT with a nonorthogonal mesh, a cursory sensitivity study is accomplished to assess the effect of the crack shape of a through crack on the K.

 

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