Flow testing of viscoelastic materials. Design and calibration of the Roberts‐Weissenberg Model R8 rheogoniometer

The rheogoniometer is an instrument for the analysis in space and time of the complete stress distribution in a viscoelastic liquid subjected to a known shearing action. A greatly improved form of the instrument is described which affords increased accuracy, electronic measurement of the various components of stress for rapid recording, and a more elaborate drive. This incorporates in a single instrument the alternative actions of unidirectional laminar shear, oscillatory laminar shear, a superposition of these two, and a predetermined acceleration to or deceleration from the first type. With this drive, an independent vibrational analysis of the mechanical properties of the material in its “rest” state or in any steady state of shear can be made.