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Study of fracture mechanisms and damage development in brittle-matrix composites. [Under longitudinal tensile loading]

Thesis/Dissertation ·
OSTI ID:7292525

The objective was to develop constitutive and failure models for composite materials based on observed damage mechanisms and damage development. The behavior of a unidirectional and cross-ply ceramic-matrix composite under longitudinal tensile loading was studied. The material investigated was SiC/CAS, calcium aluminosilicate glass ceramic reinforced with silicon carbide fibers. Unidirectional and cross-ply specimens were loaded under the microscope in a specially designed fixture. Failure mechanisms were observed in real time and recorded by photomicrography and video photography. For the longitudinal loading, experimental results were compared with predictions from a modified shear lag analysis. An elasticity analysis was conducted in order to explain the crack generation in the transverse region. The stresses were obtained and plotted as a function of the interphase modulus and the geometry of the material. The analytical results were in agreement with the experimental observations.

Research Organization:
Northwestern Univ., Evanston, IL (United States)
OSTI ID:
7292525
Country of Publication:
United States
Language:
English