Soft Matter at the Thermal Scale, Ch Rubber elasticity, swelling and gelation
Problem
A vulcanised rubber cord has shear modulus G=0.55MPa. It is stretched uniformly along its length to a stretch ratio λ=2.5 (i.e. it is 2.5 times its unstretched length). Treat the cord as an incompressible affine Gaussian network in simple uniaxial tension. (a) Calculate the nominal (engineering) stress, defined as force over the undeformed cross-sectional area.