Composite Materials Research Progress

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Yuanxin Zhou, Hassan Mahfuz, Vijaya Rangari et al.
simulation technique to simulate the tensile failure process of unidirectional layered
composites were also established to describe stress-strain relationships.
Introduction
Carbon fiber reinforced polymer matrix composites due to their high specific strength and
specific stiffness have become attractive structural materials not only in the weight sensitive
aerospace industry, but also in marine, armor, automobile, railways, civil engineering
structures, sport goods, etc. Generally, the in-plane tensile properties of the fiber/polymer
composite are defined by the fiber properties, while the compression properties and properties
along the thickness dimension are defined by the characteristics of the matrix resin.
Epoxy resin is the most commonly used polymer matrix for advanced composite
materials. Over the years, many attempts have been made to modify the properties of epoxy
by the addition of either rubber particles [1-2] or fillers [3-4] so that the matrix-dominated
composite properties are improved. The addition of rubber particles improves the fracture
toughness of epoxy, but decreases its modulus and strength. The addition of fillers, on the
other hand, improves the modulus and strength of epoxy, but decreases its fracture toughness.
Usually, the typical filler content needed for significant enhancement of these properties can
be as high as 10-20% by volume. At such high particle volume fractions, the processing of
the material often becomes difficult, and since the inorganic filler has a higher density than
the resin, the density of the filled resin is also increased. Nanoparticle filled resins are
attracting considerable attention since they can produce property enhancement that are
sometimes even higher than the conventional filled polymers at volume fractions in the range
of 1 to 5%. It has been established that adding small amounts of nano-particles (