Compression failure of fibrous laminated composites in the presence of stress gradients: Experiment and analysis
A series of experiments were performed to determined the mechanism of failure in compressively loaded laminated plates in the presence of stress gradients generated by a circular cutout. real-time holographic interferometry and in-situ photomicrography of the hole surface, were used to observe the progression of failure. The test specimens are multi-layered composite flat plates, which are loaded in compression. An underlying objective of the present investigation is the identification of the physics of the failure initiation process. It is revealed that the failure is initiated as a localized instability of the 0{degree} plies at the hole surface, approximately at right angels to the loading direction. This instability emanating at the hole edge and propagating into the interior of the specimen with the 0{degree} plies is found to be fiber microbuckling. This initial failure renders a narrow zone of fibers with the 0{degree} plies to loose structural integrity. Subsequent to the 0{degree}-ply failure, extensive delamination cracking is observed with increasing load. The through thickness location of these delaminations is found to depend on the position of the 0{degree} plies. A simple mechanical model is presented for the microbuckling problem.
- Research Organization:
- California Inst. of Tech., Pasadena, CA (USA)
- OSTI ID:
- 5611737
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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