Characterizing static and fatigue interlaminar fracture behavior of a first generation graphite/epoxy composite

Conference · Wed Dec 31 04:00:00 EST 1997

OSTI ID:675575

Koenig, M; Krueger, R; Kussmaul, K; Alberti, M von ^[1]; Gaedke, M ^[2]

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1. Univ. of Stuttgart (Germany)
2. German Aerospace Research Establishment, Braunschweig (Germany). Inst. for Structural Mechanics

The characterization of interlaminar fracture--with the goal to obtain a database that can be used in design--is demonstrated for a first generation graphite/epoxy composite widely used by European aircraft manufacturers. Critical energy release rates for Mode I and Mode II failure have been obtained from static tests using double cantilever beam, end notched flexure, and transverse crack tension specimens. An interaction criterion for the mixed mode case is formulated based on the results from mixed mode bending tests. Fatigue tests have been carried out to determine the Paris law parameters for pure Mode I, pure Mode II, and mixed mode conditions as well as threshold energy release rates that could be used as a design limit in a no-growth concept. In accordance with the static case, an interaction criterion is formulated for the crack growth rate under mixed mode conditions. Delamination progression in more complex specimens has been measured, and mixed mode energy release rates have been computed along the delamination fronts. Results lie well within the scatter band of the Paris law as obtained by the specimens employed for characterization. This confirms that the data obtained from the characterization of interlaminar fatigue growth can be applied for predictions in design.

• OSTI ID: 675575
• Report Number(s): CONF-9605345--
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
COMPOSITE MATERIALS
CRACK PROPAGATION
EPOXIDES
FAILURES
FATIGUE
FRACTURE MECHANICS
GRAPHITE
MECHANICAL TESTS