Читать книгу The Rheology Handbook - Thomas Mezger - Страница 54

Test program consisting of four intervals, preset:

1 st interval: pre-shear phase (for t = 500 s): at γ ̇ = 5 s-1 = const

2 nd interval: upward shear rate ramp (in t = 180 s): γ ̇ = 2 to 50 s-1

3 rd interval: high-shear phase (for t = 60 s): at γ ̇ = 50 s-1 = const

4 th interval: downward shear rate ramp (in t = 180 s): γ ̇ = 50 to 2 s-1

Analysis: According to the ICA method (International Confectionery Association), the following two values are determined of the downward curve [3.1] [3.79]:

1) Viscosity value at γ ̇ = 40 s-1 as the so-called apparent viscosity η40

2) Shear stress value at γ ̇ = 5 s-1 as the so-called yield stress YS5