Understanding Yield Stress Measurements

The yield stress characteristic is a property associated with numerous types of complex fluids, where the material does not flow unless the applied stress exceeds a certain value. This is evident in everyday tasks such as squeezing toothpaste from a tube or dispensing ketchup from a bottle. It is important across a wide range of industries and applications. The determination of a stress yield as a true material constant can be difficult as the measured value can be dependent on the measurement technique. Consequently, there is no universal method and different approaches favour different industries. This whitepaper discusses the various approaches available to measure yield stress and aspects of the practical measurement set-up and test parameters needed to obtain relevant and reliable yield stress data using a rotational rheometer.