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Analysis of Composite Skin-Stiffener Debond Specimens Using Volume Elements and a Shell/3D Modeling TechniqueThe debonding of a skin/stringer specimen subjected to tension was studied using three-dimensional volume element modeling and computational fracture mechanics. Mixed mode strain energy release rates were calculated from finite element results using the virtual crack closure technique. The simulations revealed an increase in total energy release rate in the immediate vicinity of the free edges of the specimen. Correlation of the computed mixed-mode strain energy release rates along the delamination front contour with a two-dimensional mixed-mode interlaminar fracture criterion suggested that in spite of peak total energy release rates at the free edge the delamination would not advance at the edges first. The qualitative prediction of the shape of the delamination front was confirmed by X-ray photographs of a specimen taken during testing. The good correlation between prediction based on analysis and experiment demonstrated the efficiency of a mixed-mode failure analysis for the investigation of skin/stiffener separation due to delamination in the adherents. The application of a shell/3D modeling technique for the simulation of skin/stringer debond in a specimen subjected to three-point bending is also demonstrated. The global structure was modeled with shell elements. A local three-dimensional model, extending to about three specimen thicknesses on either side of the delamination front was used to capture the details of the damaged section. Computed total strain energy release rates and mixed-mode ratios obtained from shell/3D simulations were in good agreement with results obtained from full solid models. The good correlations of the results demonstrated the effectiveness of the shell/3D modeling technique for the investigation of skin/stiffener separation due to delamination in the adherents.
Document ID
20030009551
Acquisition Source
Langley Research Center
Document Type
Contractor Report (CR)
Authors
Krueger, Ronald (Institute for Computer Applications in Science and Engineering Hampton, VA United States)
Minguet, Pierre J. (Boeing Co. Philadelphia, PA United States)
Bushnell, Dennis M.
Date Acquired
September 7, 2013
Publication Date
October 1, 2002
Subject Category
Fluid Mechanics And Thermodynamics
Report/Patent Number
ICASE-2002-38
NAS 1.26:211947
NASA/CR-2002-211947
Funding Number(s)
CONTRACT_GRANT: NAS1-97046
PROJECT: RTOP 505-90-52-01
Distribution Limits
Public
Copyright
Public Use Permitted.

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