SYMPOSIA PAPER Published: 01 January 1997
STP19927S

Prediction of Delamination Growth Under Cyclic Loading

Source

The growth of delaminations in carbon fiber-reinforced epoxy (CFRE) specimens during R = 0.1 and R = - 1 fatigue loading has been studied. Artificial circular and square delaminations as well as ply cuts have been introduced at various interfaces during manufacturing to simulate a pre-damaged structure and to cause delamination growth. Criteria based on fracture mechanics will be used to describe the delamination failure. Predicting delamination growth with this approach requires the distribution of the local energy release rate along the delamination front. For obtaining this energy release rate distribution, the virtual crack closure method was found to be most favorable for three-dimensional finite element analysis as the separation of the total energy release rate into the contributing modes is inherent to the method and only one complete finite element analysis is necessary. Plots of measured delamination progression per load cycle (da/dN-values) versus computed energy release rates have been included in a Paris law diagram as obtained experimentally using double cantilever beam (DCB) specimens to characterize Mode I and end-notched flexure (ENF) and transverse crack tension (TCT) specimens to characterize Mode II failure, respectively. Computed mixed-mode results lie well within the scatter band of the experimentally determined Paris law for Mode I and Mode II failure.

Author Information

Krüger, R
Institute for Statics and Dynamics of Aerospace Structures, University of Stuttgart, Stuttgart, Germany
König, M
Institute for Statics and Dynamics of Aerospace Structures, University of Stuttgart, Stuttgart, Germany
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Details
Developed by Committee: D30
Pages: 162–178
DOI: 10.1520/STP19927S
ISBN-EB: 978-0-8031-5353-0
ISBN-13: 978-0-8031-2411-0