Calculation of stress–strain curves from relaxation data in the rubbery flow region

摘要

AbstractStress relaxation curves for polysulfone and Lexan polycarbonate are only time dependent at a constant temperature if strain is defined as ϵH= In (l/l0) and the “true” cross‐sectional areaA=A0/(1 + ϵ) is used. The strain‐independent stress relaxation curves can be used to calculate stress–strain curves at different rates of strain according to the linear viscoelastic theory. The agreement between experimental and calculated stress–strain curves is good at least up to about 60 strain in the range of 0.01 to 0.2 in./min rate of extension if an average rate of strain defined by ϵH= 1/tln