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RSA - IST

Ring Shear Assembly Handbook

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Introduction

The GDS Ring Shear Tester (GDS Ring Shear) uses continuous rotation providing an alternative option to a multiple reversal residual shear test. It is a self-contained stepper motor-driven unit that can be controlled either manually using a Smart Keypad, or from a PC via the USB interface. When used with the GDSLAB control and data acquisition software, the GDS Ring Shear can be used for a complete array of tests depending on what data is needed from the test.

This handbook provides the user with a guide to the GDS Ring Shear, covering the following aspects of the system:

• Set up of the system hardware

• Set up of the system software

• System operation via the Smart Keypad

• System operation via the GDSLab software

System hardware

The standard GDS Ring Shear is comprised of the following hardware devices:

• GDS Ring Shear load frame with 5kN-200Nm DBBSS load cell (Other sizes available on request)

• 2 x 24 VDC power pack, 2 x IEC mains leads (with user-specific plug), and 2 x USB cables

• Smart Keypad

• Optional +/- 12.5mm external displacement transducer, connection either:

  • via serial pad (data logger)

  • via Digital Remote Feedback Module (DigiRFM)

• Ring Shear Cell, 100mm OD and 70mm ID

System software

The GDSLab software is used to automate the testing process for Ring Shear testing to BS 1377 part 7 and ASTM D6467. This requires the use of the following GDSLab test module:

• Standard Shear

System features

• Self-contained unit with no requirement for reversal testing

• Automated consolidation and rotational testing via GDSLab control

• Simple USB interface to PC for both the GDS Ring Shear load frame axis

• 360-degree continuous platen travel

Important information

*The system should be set so that any external displacement transducer that is fitted will not reach full travel before the axial extension is reached. This is either in axial loading or axial displacement control. Failure to observe this could result in damage to the displacement transducer.

Setting up the System

The GDS Ring Shear is initially installed by completing the procedures listed in the hardware and software sections below. 

Setting up the GDS Ring Shear hardware

Step 1 – Remove the GDS Ring Shear load frame from the shipping crate. The frame will be packaged with the control boxes separate and any additional items such as the cell will most likely be in separate boxes.

Step 2 – Remove the Smart Keypad from the packaging and place on front mounting bracket. This is held in place with the magnetic strip attached to the top of the controller and the strip magnet attached to the back face of the Smart Keypad.

Step 3 – Attach the keypad cables to the RFM (optional: only if it’s attached to the side and part of the order) The Axial Control Keypad connects to the Displacement RFM and the Radial Control Keypad connects to the Pore Pressure RFM. The back of RFM has two CAN cable connections, it doesn’t matter which one is used for the keypad and the IST.

Step 4 - Following the previous two figures above, plug in:

• The load cell connectors (color match)

• IEC main lead connector

• CAN cables from the RFM(s) (optional: only if it’s part of the order) or keypads

• USB connectors to/from laptop

Step 5 – If an additional transducer is being used via an RFM please see section Appendix A: Smart Keypad Functions on using an RFM

Step 6 - Secure the load cell and the shearing interface top cap with the Mechalock fittings. To do this first set the Mechalock in place and tighten by hand. Once the parts are holding in place they need to be tightened up using a 41mm spanner.

Setting up the GDSLab software

Step 1 – Open the GDSLab handbook (either hardcopy or in .pdf format) supplied with the system and follow Section 2 to install the latest version of GDSLab on the PC.

Steps 2 – Connect the USB leads to the test PC and then switch the power on the IST. This will enable the USB drivers required to communicate with the load frame to automatically finish installing on the PC.

Step 3 – Launch GDSLab and create a new station (or stations if using more than one GDS Ring Shear) using the .ini file (e.g. “GDS Ring Shear.ini”) supplied with the GDSLab USB. The alternative ini file is “GDS Ring Shear DigiRFM Displacement.ini” (or similar) if the order has RFM(s) attached.

Step 4 – Open the ‘Object Display’ and click on the GDS Ring Shear Load frame image for the appropriate axis. This will display the Controller selection tool, which enables connection to the control box based on the selection of the GDS serial number (these can be found on the back of the control boxes). To select the appropriate control box click on the serial number associated with the axis.

Step 5 – Click on the ‘TX/CP’ button at the top of the ‘Object Display’ window, then on the ‘Read’ button to display the transducer readings from the GDS Ring Shear. If the values correspond (and have a blue font) to those on the Smart Keypad, the system has been successfully set up. Otherwise, create a support ticket on our website.

Operating the System 

The GDS Ring Shear can be operated via two control methods: manually using the Smart Keypad, and automated control via the GDSLab software. To conduct a test, both methods are generally used, as the Smart Keypad allows the physical system to be set ready for testing, whilst GDSLab automates the test load/displacement control and measurement.

Smart Keypad control

The Smart Keypad front panel is presented in the figure below with labels showing the primary display features.

The system can be operated via the Smart Keypad through the use of a number of menus and keypad buttons. A complete guide to this functionality is given in Appendix A, however, the most basic and useful functions are listed in the following:

• Unlock Keypad – To unlock the Smart Keypad to regain manual control after operation via PC, press (./-), (↵), (2), (↵), (↵)

• Target Load / Torque – To apply a specified load to the test specimen press (CMD) > (7), then type the required load value (in kN/Nm) using the numerical keypad. To begin the load application press the green ‘Enter’ button (↵)

• Target Displacement / Angle – To move the ram or cell to a specified position press (CMD) > (4) then type the required displacement value (in mm/degrees) using the numerical keypad. To begin movement press the green ‘Enter’ button (↵). Note the targeted displacement is based on the internal displacement reading, with positive readings corresponding to the ram moving downwards and the platen rotating anti-clockwise.

• Apply Load Offset – To set the load reading to zero by applying a soft zero offset press (CMD) > (CMD) > (8) > For reapplying an offset (↵) will need to be pressed after the previous commands.

• Remove load offset – To remove a previously set soft zero offset on the load reading press (CMD) > (CMD) > (9) > (↵)

• Zero Displacement Reading – To set the internal displacement reading to zero press (CMD) > (CMD) > (5) > (↵)

• Ram Extension / Positive Rotation – To move the ram upwards or to apply positive rotation at a slow rate press (5) > (↵)

• Ram Retraction / Negative Rotation – To move the ram downward or to apply negative rotation at a slow rate press (2) > (↵)

• Stop Targeting of Load / Displacement – To halt the ram/platen movement when targeting either load or position press (Stop)

GDSLab software control

The following describes the procedure for automating both consolidation and rotational tests using the GDS Ring Shear and GDSLab software.

Step 1 – Load GDSLab and corresponding system .ini file. The Object Display may then be opened to check all transducers (‘Load’, ‘Displacement’, ‘Torque’, and ‘Degrees’) are reading correctly, or used to target load and displacement values.

Step 2 – Ensure a small seating load has been applied to the test specimen, then close the Object Display. After entering the necessary ‘Data Save’ parameters into the ‘Test Plan’, click the ‘Sample’ button. At this point, the ‘ShearBox’ specimen type should be selected, followed by the Test Standard used in your region and specimen details (including initial height and diameter).

Step 3 – Click on the ‘Add Test’ button and select the ‘GDS_ssStandard_Shear’ test module. The ‘Create New Test Stage’ button can then be used to specify the first stage of the specimen test. Instructions on how to reach the rotational settings are set out below:

• Select the test type “Ring Shear” for the current stage in the test. Fill in the test values and then proceed to the next window. (The first stage will most likely be monitoring the initial change during water induction)

• Enter any termination settings required for the test and proceed to the second termination condition window

• Apply any extra termination conditions required for the test in the top section of this screen. A time limit can also be entered in the lower section of this window.

• Once all the details have been entered the stage can be added to the test list

Step 4 – Once at least one test stage has been created, the ‘Add To Test List’ button may be clicked and the ‘Go to Test’ button used to load the ‘Test Display’, allowing the test to be started.

Step 5 – The test data file should be accessed following completion of the test.

Setting an additional transducer as the Control Source

The Ring Shear control box has the option to add a ‘Remote Feedback Module’ to the system - which essentially adds another transducer to the Controller to be logged by GDSLAB. 

For instruction on changing between either Axial load or Torque and an additional transducer as the primary control source, see the ‘DigiRFM Settings’ section in Appendix A.

A typical setup would be to add a DigiRFM with +/-5 or 10mm Displacement Transducer to the Axial Control. This will allow a much more direct measurement of the axial deformation. It can also then be set to control via this additional transducer.

Cell Installation

This step-by-step guide below details a way to install the specimen confining ring and bath. By the end of this process, the system will be set and ready to run a test.

Step by Step guide to cell installation

Appendix A: Smart Keypad Functions

The table below lists the Smart Keypad buttons shown in the keypad figure above, along with their associated functions. To call up the functions displayed below each of the numbers (i.e. 0 to 9 and ./-), the selected button must first be pressed, followed by the green ‘Enter’ button(↵).

List of Smart Keypad buttons and their associated functions

Descriptions of each menu available to be accessed from the Smart Keypad are given in the following:

Command Menu – allows two pages of functions to be accessed quickly. The required function is called up by pressing the associated number.

• Target Load (7) – specify a load value (in kN) to be applied to the test specimen. (Axial Keypad)

  • Target Torque (7) – specify a load value (in Nm) to be applied to the test specimen. (Radial Keypad)

• Target Position (4) – specify a displacement value (in mm) for the ram. (Note this value refers to the internal displacement platten reading.) (Axial Keypad)

  • Target Angle (4) – specify an angle (in deg) for the platen. Note this value refers to the internal displacement reading. (Radial Keypad)

• Fast Extend (6) – move the ram downwards at a fast rate. (Axial Keypad)

  • Fast Extend (6) – rotate the platen anticlockwise at a fast rate. (Radial Keypad)

• Fast Retract (3) – move the ram upwards at a fast rate. (Axial Keypad)

  • Fast Retract (3) – rotate the platen clockwise at a fast rate. (Radial Keypad)

• System Menu (0) – open the System Menu. (Both Keypads)

• Apply LoadOffset (8) – apply a soft zero offset to the load reading. (Axial Keypad)

  • Apply TorqueOffset (8) – apply a soft zero offset to the torque reading. (Radial Keypad)

• Zero Pos Reading (5) – zero the internal displacement reading. (Both Keypads)

• Remove LoadOffset (9) – remove any soft zero offsets applied to the load reading. (Axial Keypad)

  • Remove TorqueOffset (9) – remove any soft zero offsets applied to the torque reading. (Radial Keypad)

• Set Speed (7) – set the maximum speed at which the ram can move. (Axial Keypad)

  • Set Speed (7) – set the maximum speed at which the paten can rotate (Radial Keypad)

Main Menu – allows the primary GDS Ring Shear menus to be accessed, which contains all sub-menus displayed in the figure below for the axial axis.

Set  Pos/Load menu  –  allows load/Torque and displacement/angle values to be targeted, and maximum ram/rotational speeds to be set.

• Set Load – specify a load value (in kN) to be applied to the test specimen. (Axial Keypad)

  • Set Torque – specify a torque value (in deg) to be applied to the test specimen. (Radial Keypad)

• Set Position - specify a displacement value (in mm) for the ram. Note this value refers to the internal displacement reading. (Axial Keypad)

  • Set Angle – specify an angle (in deg) for the platen. Note this value refers to the internal displacement reading. (Radial Keypad)

• Set Speed – specify the maximum speed (in mm/s) at which the ram can move. (Axial Keypad)

  • Set Speed – specify the maximum speed (in deg/s) at which the platen can rotate. (Radial Keypad)

• Reset Speed – resets the platen speed to the maximum allowable value. (Axial Keypad)

  • Reset Speed – resets the rotation speed to the maximum allowable value. (Radial Keypad)

Extend/Retract menu – allows the ram or platen to be moved/rotated at slow or fast speeds.

• Fast Extend – moves the ram downwards at the maximum allowable speed. (Axial Keypad)

  • Fast Extend – rotates the platen anticlockwise at the maximum allowable speed. (Radial Keypad)

• Fast Retract – moves the ram upwards at the maximum allowable speed. (Axial Keypad)

  • Fast Retract – moves the platen clockwise at the maximum allowable speed. (Radial Keypad)

• Slow Extend – moves the ram downwards at the speed set by the user within the ‘Set Pos/Load’ menu. (Axial Keypad)

  • Slow Extend – moves the platen anticlockwise at the speed set by the user within the ‘Set Pos/Load’ menu (Radial Keypad)

• Slow Retract – moves the ram upwards at the speed set by the user within the ‘Set Pos/Load’ menu. (Axial Keypad)

  • Slow Retract – moves the platen clockwise at the speed set by the user within the ‘Set Pos/Load’ menu. (Radial Keypad)

Offsets Menu – allows a soft zero offset to be applied to the load/torque reading, and a DigiRFM transducer if attached.

• INT Offsets – open to apply or remove a soft zero offset from the load cell reading.

• RFM0 Offsets - open to apply or remove a soft zero offset from an additional transducer reading (only possible when a DigiRFM transducer is connected).

Ramp/Cycle menu – allows both load/torque and displacement/angle values to be ramped or cycled.

• Pos Ramp/Cycle – specify the parameters to ramp or cycle the applied displacement/angle

• Load Ramp/Cycle – specify the parameters to ramp or cycle the applied load/torque

To perform either a load or displacement ramp/cycle or a torque or angle ramp/cycle the following parameters must be selected:

• Wave type:

  • Ramp (+) = increases the load/torque or displacement/angle value linearly

  • Ramp (-) = decreases the load/torque or displacement/angle value linearly

  • Sine = varies the load/torque or displacement/angle using a sinusoidal waveform

  • Triangle = varies the load/torque or displacement/angle using a triangular waveform

  • Square = varies the load/torque or displacement/angle using a square-shaped waveform

• Datum: For Ramp (+) and Ramp (-) wave types, specify the load/torque or displacement/angle from which to begin the ramp function. For Sine, Triangle, and Square wave types, specify the load/torque or displacement/angle for which the cycling will center.

• Period: For Ramp (+) and Ramp (-) wave types, specify the time to move from the specified datum to the load/torque or displacement/angle target (as entered into the Amplitude setting). For Sine, Triangle, and Square wave types, specify the period of the cycle (i.e. time to complete one cycle).

• Amplitude: For Ramp (+) and Ramp (-) wave types, specify the load/torque or displacement/angle target relative to the datum (e.g. if the datum is set at 0.1 kN, and the amplitude is set at 1.0 kN, the ramp will move from 0.1 kN to 1.1 kN). For Sine, Triangle, and Square wave types, specify the amplitude of the load/torque or displacement/angle during cycling (e.g. if the datum is set a 0.0 mm, and the amplitude set at 1.0 mm, the cycle will move between -1.0 and +1.0 mm).

• Cycles: specify the number of load/torque or displacement/angle cycles to be applied to the test specimen (not required for Ramp (+) and Ramp (-) wave types).

• Phase:  set a  phase offset when cycling the load/torque or displacement/angle  (e.g. if a  +90 degree offset is specified when the datum is set at 0.0 mm and the amplitude 1.0 mm for a Sine wave type, the displacement cycle will begin from 1.0mm).

System Menu – allows the system settings and details to be accessed and altered.

• Reset Menu – open to restarting the Smart Keypad or the attached control box load without powering off the system.

• Lock/Unlock  –  open to lock the  Smart  Keypad to prevent accidental keypad commands from being pressed, or unlock the Smart Keypad after locking or PC control has taken place.

• Limits Menu – open to view the system limits (maximum load = 5.1 kN; minimum load = -1.0 kN), reset the virtual end stops (these are triggered when the ram reaches its physical end limits), set user-defined load/torque and displacement/angle limits, and clear user-defined load/torque and displacement/angle limits.

• DigiRFM Settings – open to set the control source for the GDS Ring Shear Axis Depended.

The DigiRFM can be set as the primary control source instead of the 5kN load cell or the 200Nm load cell. In such a case all functions previously assigned to load/torque (e.g. CMD option ‘7’, ‘Set Load/torque’ etc.) are re-assigned to allow control of the additional transducer.

• Diagnostics – open to view diagnostic information relating to the GDS Ring Shear and Smart Keypad.

• System Calibration – open to view details of the load/torque and displacement/angle calibration

details for the system

• Event Log – open to view or clear the system event log.

• Display Setup – open to view or alter the Smart Keypad display settings and time before screensaver becomes active.

• About – open to view information about the Smart keypad

• Factory Mode – open to restore the system to the GDS factory settings (requires an access key from a GDS engineer).

*For further advice regarding the GDS Ring Shear, please contact the GDS support team directly by:

• visiting http://gdsinstruments.helpserve.com/

• emailing support@gdsinstruments.com