Explanation

The ability of a fluid to resist tensile deformation. The ratio of tensile stress and tensile strain rate on the cross sectional area of macromolecule materials is called tensile viscosity. Like shear viscosity, tensile viscosity is also dependent on strain rate. In the range of low stress or low strain rate (i.e. under Newtonian flow conditions), the uniaxial tensile viscosity is 3 times of the shear viscosity, and the biaxial tensile viscosity is 6 times of the shear viscosity. At high stress and high strain rate, the change of tensile viscosity varies with the type of macromolecule, and there may be tensile thinning, tensile hardening and other phenomena. The tensile viscosity of macromolecule materials has an important influence on its spinning, film blowing, foaming and other molding processes.

Classification