The GDSRSA allows torsional ring shear tests, under drained conditions by the rotational shearing action applied continuously by an electromechanical stepper motor until a constant residual shear stress is achieved. During testing there is no change in the specimen cross-sectional area of the shear plane. The GDS ring shear applies a consolidation stress with the use of a GDS force actuator, this is controlled and recorded with the use of a PC (USB connected) and an external load cell that measures the axial & shear stress directly applied to the specimen. 

Key features	Benefits to the user
Compact size and weight:	The benchtop system has small footprint (51 x 32cm) and low weight (30kg)making it easily manoeuvrable.
Fully contained system:	The GDS Ring shear has no extra requirements for a data acqusisiton device, large weights, extra external dial gauges or load rings, all required connections and equipment is housed directly in the machine.
External Local LVDT:	With a closed loop external LVDT recording axial displacement, compliance within the system is removed allowing for more accurate testing.
Active height control allows for constant volume ring shear tests to be performed:	Determination of liquifeid shear strength, a test which requires significant shear strain and height control (constant volume), so ideal in the GDS GDSRSA.
Interchangeable pedestals & topcaps:	Allows one machine to test a variety of specimen sizes (if required). The pedestal and topcaps are secured within the frame using locking clamps.
Axial Displacement connect via DigiRFM:	Closed loop for axial displacement increase response when using displacement/ strain targeting.
Lower section drainage for specimen:	Allows drainage of specimen during testing.
Randomised disk pattern:	Reduces specimen ruffling.
2 x USB cables for PC control:	Allows user friendly method of connecting to any modern PC.

Dimensions	51 x 32 x 116cm
Load Range (kN)	5
Power	100-240V 50/60Hz 1.5A single phase
Sample Sizes	100mm OD x 70mm ID (Other sizes available upon request)
Weight Approx (kg)	30