The Response of Fiber-Reinforced Elastomers under Simple Tension

Abstract

The mechanical behavior and basic response mechanisms of fiberreinforced elastomers (flexible composites) can be significantly different from those of typical advanced “stiff” composites. This paper presents experimental results of elastomer (rubber) matrices, dry and impregnated fibers, and four sets of fiber-reinforced elastomeric composite, summarizes the corresponding initial and nonlinear orthotropic constitutive properties, and sheds light on fundamental response mechanisms. Silicone and urethane rubber were combined with fiberglass and cotton reinforcing fibers. Balanced angle-ply laminates of each material system were fabricated with off-axis angles ranging from 0° to 90° in 15° increments. Dog-boned test specimens, 76 mm (3 in) long, were fabricated with fiber volume fractions ranging from 12% to 62% using a previously documented non-calendering fabrication method [1–3]. The average extensional stiffness of individual twisted cotton fibers increased 74% to 128% when impregnated with an elastomer. Fiber-reinforced elastomer laminate stiffness and nonlinearity can vary significantly with fiber angle. The nonlinear stiffening or softening trends of the silicone and urethane rubbers are reflected in their respective fiber-reinforced elastomers. Longitudinal stiffness at low off-axis angles is a function of the reinforcement stiffness. At high off-axis angles, longitudinal stiffness and strength are functions of fiber type, fiber volume fraction and elastomer.

Keywords

fiber-reinforced elastomer flexible composites elastomer composites tensile test results nonlinear material properties nonlinear response mechanisms smart structures

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