Study of Evolutions of Shear Bands in Yield-stress Materials Under Transient Shear

Yield-stress materials are involved in a lot of industries processes. Understanding their rheological properties is crucial to product development, process flow simulations, and quality control of those materials. Yield-stress materials often show shear banding, in which an initially homogeneous fluid separates into layers of different shear rates under an imposed shear flow. Shear banding greatly alters the local shear histories and impacts the bulk rheology. In this webinar, we show how to perform time-resolved velocimetry measurement on the Anton Paar MCR702 TwinDrive rheometer to study the evolution of shear bands. We use two model fluids as examples – an oil-based fumed silica suspension and a water-based Carbopol gel. Both materials exhibit significant shear banding under transient and oscillatory shear.