Composite Materials

· For fracture in a composite with a fiber fracture strain less than the matrix fracture strain, two fiber volume fractions of special interest.
· The initial introduction of fibers decreases the composite strength, with the lowest strength occurring at V_min , the intersection point of the two failure modes:
V_min = (σ^*_m - σ_m)/(σ^*_m +σ^*_f - σ_m) .

· The fiber content at which the uniaxial composite reaches the fracture strength of the matrix is V_crit and is given by:
V_crit = (σ^*_m - σ_m) /(σ^*_f - σ_m) ~ (σ^*_m/σ^*_f)