Feedback and control system and method for rheometer shearing stress in unsteady test phase

Abstract

The invention discloses a feedback and control system and method for rheometer shearing stress in an unsteady test phase. The method comprises the steps that on the premise that a rheological curve of a test sample is smooth and continuous, discretization is conducted in a rheometer initial torque loading time domain; a mathematic relation between the actually-measured rotor angle speed and the torque should be applied at a next moment is determined; the rotor angle accelerated speed of the next moment is approximately acquired according to the measured rotor speed, and a torque value should be applied at the next moment is calculated according to preset shearing stress, the rotor angle accelerated speed and the rotating inertia of a rheometer rotating part, and control is conducted with the torque value. Accordingly, it is guaranteed that the real shearing stress on the rotor surface accords with a preset value, and the system and method are suitable for a rheological test operated under the condition that shearing stress loading is controlled by fluid of which the rheological property is related with time and have the certain universality and applicability.

Description

technical field [0001] The invention relates to a rheometer shear stress feedback control system and method in an unsteady test stage. Background technique [0002] Various fluids are involved in various fields such as industry, medical treatment, food, and life. Researching the rheological properties of different materials is an inevitable requirement for in-depth understanding of their fluid properties and their application. Therefore, the accuracy of material rheological measurement will be the key to accurately understanding its rheological properties. With the rapid development of intelligent rheometers, advanced rotational rheometers such as Anton Paar in Austria and HAAKE in Germany are playing an important role in the field of rheological measurement. [0003] For time-independent fluids such as Newtonian fluids and power-law fluids, the rheological data is usually tested after the rheometer rotates stably. For viscoelastic and thixotropic materials such as polymer...

AI Technical Summary

Problems solved by technology

However, for the test process under the mode of "controlled shear stress", such as "constant shear stress", the rheological test system applies "constant torque" according to formula (1), but due to the unsteady rotation of the rotor, the formula (4 )middle is not 0, which causes the real shear stress on the rotor surface to deviate from the preset value

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