Analysis of Delamination Onset and Growth in Curved Laminates

by Roderick H. Martin, Analytical Services and Materials, Hampton, United States,

Document Type: Proceeding Paper

Part of: Mechanics Computing in 1990's and Beyond


This paper details an analysis to characterize delamination onset and growth from a matrix crack in a curved composite laminate. Finite element analysis was used to determine values of strain energy release rate (G) which can be compared to the interlaminar fracture toughness of the composite for delamination onset predictions. The delamination was assumed to grow from a matrix crack in the curved section and the front was assumed to remain straight and perpendicular to the edge. G was seen to be larger at the free edges than in the center. Overall, G increased with delamination growth. Therefore, once delamination begins from the matrix crack it should continue around the curved section with no increase in applied load. In the vicinity near the matrix crack the rate of change of G was observed to decrease initially and then begin to increase with a point of inflection in between. Using the measured failure loads and the interlaminar fracture toughness of the composite, it was shown that the point of inflection corresponds to the critical value of G.

Subject Headings: Delaminating | Laminated materials | Cracking | Composite materials | Matrix (mathematics) | Finite element method | Curvature | Failure loads

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