Rheology is the study of flowing liquids or viscous materials. As such it covers properties related to the flow behavior of liquids and the temporary and/or permanent deformation of (semi-) solid materials. These are typically known as viscous, visco-elastic and elastic properties. These properties can be measured using a rheometer both in a static and/or a dynamic environment. Typical factors affecting these properties can be external forces, temperature, duration of stress, creep, chemical changes in a material (e.g. curing, chemical-aging).
Rheological studies can be used to perform process modeling, e.g. to mimic or optimize process conditions, such as in plastic (reaction) injection molding, 3D printing, or in the UV and thermal curing of adhesives. A rheometer measures material properties in rotary or oscillatory measurement mode in response to an applied force.
Various measurement configurations are possible, depending on the material or desired property to be measured. Common examples are cone-plate, plate-plate and cylinder-cup configurations. Software is used to accommodate these different measurement configurations and calculations are done to derive the physical properties of interest.