THE EFFECT OF FIBER ARCHITECTURE ON THE MECHANICAL-PROPERTIES OF CARBON CARBON FIBER COMPOSITES/

The mechanical performance of carbon-fiber matrix composites with diff erent fiber architectures is investigated for various loading modes. A il the composites were fabricated from nominally equal constituents an d identical consolidation processes, leaving as the only variables, th e variations caused by the different fiber weave structures. The fiber architecture drastically affects both composite strength and deformat ion characteristics. Some systems are almost linear up to a final brit tle failure while others exhibit a pronounced non-linearity prior to f ailure. It is found that the composite tensile strength is dictated by both fiber volume fraction and weave architecture. The weaving can ha ve a beneficial effect in spite of introducing new fiber flaws and str ess concentrations, because it causes the composite to be less flaw se nsitive. These features are addressed analytically by considering the statistical aspects of the fiber strength and the formation of critica l defects.