Zero-shear viscosity
= Zero-shear viscosity
{title2=$\mu=\int_0^\infty G(s)\,ds$}
For an integrable <relaxation modulus>, a small constant shear rate sustained from the remote past gives stress equal to that rate times the displayed integral, including any instantaneous solvent mass. For the linear <Oldroyd-B model> it is $\mu_0+G_0\tau$. A nondecaying elastic modulus would make this integral infinite rather than describe a fluid with finite steady viscosity.