Numerical search for morphologies providing ultra high elastic stiffness in filled rubbers

We have numerically studied the transverse elastic behavior of a unidirectional composite comprising non-overlapping silica fibers dispersed in a rubber matrix. Some composite morphologies that provided an ultra high transverse shear modulus at rather moderate silica loadings were identified. For these morphologies, predicted elastic stiffening levels were in agreement with those measured at low strains in carbon black and silica filled rubbers, leading one to surmise that such elastic stiffening may also play an important role in the low strain mechanical responses of actual carbon black or silica filled rubbers.