Large deformation non-linear response of fiber-reinforced elastomers: glass fibers-polydimethylsiloxane laminates

Soft fibers-reinforced composites are promising materials for several applications as flexible actuators and in bio-mechanical devices. They are based on elastomeric polymers that allow ranges of deformation much larger than those of conventional thermosetting polymer-based composites. In order to investigate the behavior of these composites, quasi-static monotonic and cyclic tensile tests in uniaxial loading c onditions have been carried out on continuous glass fibers-polydimethylsiloxane laminates with stacking sequence [+θ,-θ]2S, with θ = 30, 45, 60 and 75°. The stress-strain curves obtained show a linear response of the materials at small strains, a “softened” response at intermediate strains and a strain induced “hardening” at large strains. An extensive fibers reorientation was observed during loading. Large reduction in the specimens width was also measured and an increase in their thickness was observed. Loading-unloading tests showed a pronounced hysteresis and strain induced softening was also observed. These experimental observations underline the importance of a deep characterization of elastomeric matrix composites.