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Interphase Mechanics in Fatigued Carbon Fiber Composite Materials

ROBERT HAYNES, TODD HENRY, DANIEL COLE

Abstract


The mechanisms of fatigue damage in carbon-fiber-reinforced-polymer (CRFP) composites are governed by complex material damage accumulation behaviors which depend on the reinforcement orientation and loading conditions. A common failure mode is destruction of the fiber-matrix interface through which loading is transferred through shear strain from the matrix to the fiber. It is believed that a mechanically distinct interphase region exists between the fiber and matrix, and that this region is degraded in fatigue loading. In this research, the fiber, matrix, and interphase behavior is investigated for unidirectional IM7-8552 specimens of the laminate [013] mechanically tested in three-point bending to failure. The thermodynamic and quasistatic mechanical properties are presented from an investigation via nano-indentation and atomic force microscopy (AFM). Room temperature and elevated testing at various frequencies was used on neat resin as well as [013] fatigued and control specimens.


DOI
10.12783/asc2017/15302

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