September 22, 2021 @ 11:00 AM EDT
Webinar via Zoom
A new measuring device concept is introduced which combines an electronically commutated (EC) motor as a rotational top drive and a moving magnet linear drive or another rotational EC motor, as bottom drive to enable rheological measurements and dynamic mechanical analysis (DMA) on one single device.
The concept enables various modes of operation by using different combinations of the bottom drive. Three different testing modes can be realized when using the upper rotational EC motor and additionally a second rotational EC motor as the bottom drive. While the use of the upper EC motor allows one to perform measurements in combined motor transducer (CMT) mode, the use of both EC motors allows one to work in the separate motor transducer (SMT) mode and the counter movement mode on one device. CMT mode not only allows all tests and options a single drive rheometer can do but advanced powder rheology characterization in the fluidized dynamic state through the use of a classical pressure drop device attached to the rheometer are also possible. A ring shear cell attached to the rheometer in CMT mode allows one to do quasi-static characterization of granular materials at elevated temperatures and humidities. In the separate motor transducer (SMT) mode the bottom motor acts as the actuator and the top motor acts as the torque transducer.
A SMT mode has advantages in sensitivity under certain measurement conditions and allows the use of special tools such as a cone-partitioned-plate (CPP), which enables measurements with edge fracture prone samples, extended frequency sweeps with soft materials such as pressure sensitive adhesives where inertia of the measuring drive can effect results etc., In counter movement mode both motors rotate or oscillate in opposite directions which enables the creation of a stagnation plane in the sheared sample which could be beneficial for investigation of Taylor-Couette instabilities or extending the range of shear rates for high shear rheology applications or for rheo-microscopy, since the structures under investigation are not moving out of the field of view when shear is applied. In addition, combining the upper rotational motor with a linear drive in the bottom permits one to apply force and deflections in the axial direction.
This is suitable to perform dynamic mechanical analysis in bending, tension, compression, and torsion. DMA in tension by the linear drive and DMA in torsion by using the upper rotational drive are possible on the same specimen which allows one to extract the Poisson’s ratio of the material. In this talk benefits of having such a modular device configuration in different modes will be showcased via different application testing examples ranging from liquids, solids to granular materials.
Dr. Abhishek Shetty is the Lead Scientist for the Rheology division at Anton Paar USA. Dr. Shetty received his BS degree in Chemical Engineering from National Institute of Technology Karnataka and MS and PhD from University of Michigan, Ann Arbor, USA. Dr. Shetty has over 10 years of working experience in the CPG and Advanced instrumentation space. He has extensive expertise in new product and process development, leading large commercialization teams, discovery projects, new technology evaluation and new product innovation. As Lead Scientist for Rheology at Anton Paar USA, Dr. Shetty’s work includes partnering with business and collaboration partners in academia and industry to discover new testing needs. He works closely with teams across the globe to develop new applications pertaining to rheology using advanced rheometric tools. In his current role he also present papers at several technical conferences and also serves as the main contact point for the scientific community in the US representing the Antor Paar, USA rheology department.