Flow and Yield Characteristics of Yield Stress Fluids Using Hysteresis Loop Test Below Slip Yield Point

The flow characteristics of an alpha-gel O/W emulsion, which is a yield stress fluid, was investigated. The hysteresis loop test was conducted for the strain below the slip yield point, and the single relaxation Maxwell model was used to fit the experimental data. Using these methods, the shear-rate dependence, stress dependence, and time dependence of the viscoelastic properties of the sample were evaluated in the region below the slip yield point. The shear-rate dependence induced by the stress-ramp rate and the stress dependence from the maximum applied stress influence the viscoelastic characteristics below the slip yield point in terms of the flow history. However, the time dependence of the viscoelastic characteristics could not be confirmed for any creep time. The yield stress measured in the stress-ramp test increases with the stress-ramp rate owing to the contribution of the viscous strain from the flow history.