This stand-alone electromechanical test apparatus is a robust construction device including of 2 dynamic force actuator and high-quality mechanic and electronic components which produces repeatable test results, and the quality makes it suitable for research and also usual test applications.
The device gives the possibility to perform tests on different sample sizes up to 150mm (simple shear test) in diameter and also can run direct shear tests up to 100mm sample size. The frame is a is a frame is heavy construction with high stiffness to reduce the deflection and vibrations which could influence the accuracy of measurements during dynamic repeated loading tests.
It applies vertical and horizontal independent loads by electromechanical dynamic actuators which enables each axis to be controlled in displacement (strain or velocity) mode as well as load control.
The main advantage of device is an accurate testing of soil parameters without tilting and friction between shear test components. The high quality and low friction doublelinear guides used to ensure strength and alignment without tilting in normal and shear directions.
The normal stress and the shear stress are closed loop controlled by an electromechanical drive system.
The cylindrical sample is mounted inside a rubber membrane and positioned inside a confining polished low friction Teflon coated rings (optional membrane with wire-mesh is also available), therefore the horizontal diameter of sample remains constant (constant section area) while the vertical settlement during consolidation is permitted. The shear stress is performed by horizontal movement which applies at the bottom of the sample relative to the top of it.
Two porous discs are located on top and bottom of the sample and two porewater ports at top and bottom gives the possibility to saturate the sample. The device is equipped with advanced GEOsys software which gives the possibility to users to run all the test stages completely automatic and there is no need of pretense of operator during the test.
Performed Tests:
• Cyclic simple shear
• Static simple shear
• Active height control
• Constant normalstiffness testing
• Direct Shear testing
• Multi-stage testing
• low speed/creep test
• User defined waveformtesting on each axis
• Axial compression and shear loading via displacement, strain or load control
System Geography
① Electromechanical Stiff stand-alone Load frame
② Two columns beam to mount the linear guides and maintain rigidity of machine
③ Two stainless steel pillars to further brace the system
④ High quality and low friction double linear guides used to ensure strength and alignment without tilting in normal and shear directions
⑤ Upper traverse
⑥ Direct Shear Test Jig
⑦ Simple Shear test Jig
⑧ Axial Load cell
⑨ Axial displacement transducer
⑩ On-0ff switch button
⑪ High Speed dynamic Controller (Integrated to load frame)
⑫ Software (Not shown here)
Dynamic Simple Shear Apparatus
The dynamic simple shear apparatus is an automated apparatus with a very high stiffness and includes of two high quality servomotor drives for performing vertical load (static and dynamic) and horizontal shear load (static and dynamic). The electromechanical drive with high resolution and closed loop control rate generates closed-loop strain and stress controlled static axial load and strain and in addition stress-controlled shear forces.
The Vertical load is performed by an actuator connected to the top of the specimen, which is rigidly fixed against horizontal movement and just perform vertical load with high accuracy. It is included of an high resolution internal displacement transducer to measure the movement of the piston with high accuracy along the height of specimen.
The other actuator performs horizontal load to the bottom of the specimen and causes shear strain. This actuator is rigidly fixed against any vertical movement and just apply horizontal load with high accuracy, it is also included of a high-resolution internal displacement transducer to measure the movement as possible.
Shear Load Cell
Special designed shear load measurement which includes of two numbers of Stiff flat two-dimensional load cells combined into one plate which are as close as possible to sample to measure the shear load more accurate. There is not any bushings or bearings between the sample and the load cell therefor the measurement is ultimate accurate without friction effects from linear guides.
The double load cell configuration excludes any friction and tilting error measurements within shear axis during testing and measurement.
K-Zero Condition
Low friction Teflon coated sample slip rings for specimen confinement ensuring a constant cross-sectional area (K-zero condition).
Peak Target Control Function
The advanced dynamic controller takes feedback from each loading cycle for next one to have a constant stress even when the stiffness of sample is changing during the test.
Active Height Control
The device has top quality double ball bearing for upper traverse where the load piston is fixed. This feature helps the axial laod cell to be positioned which is not measuring the friction from the linear guides.As the Shear load cell is located beneath the sample, the axial load cell is not too far from sample to affect the measuring.
This feature guaranties the height control in real-time with the same speed or closed-loop control time as the horizontal actuator during cyclic tests. The height of the sample during shear should not be changed more than 0.05% of initial height.
Small Rotation Of Top Cap
The main advantage of device is an accurate testing of soil parameters without tilting and friction between shear test components. The high quality and low friction double linear guides used to ensure strength and alignment without tilting in normal and shear directions. This ensures Small rotation of the top cap during shearing. All above functions make it a unique device for research applications.
Simple Shear Jig
The type of the porous discs depends on sample types and stress conditions which can be applied on sample. There is different availability for porous discs with different roughness and surface i.e. plane, grooves, ridges and embedded pins. Please note that our standard offer includes of sintered plane disk, please select your desired type of porous disc at time of quotation.
The test set up jig is comprising of:
• Low friction sample slip rings (Teflon coated)
• 1 off bottom plate with stainless steel porous plate and twporewater connections for saturation and flushin
• 1 off Top cap, parallel-guided, with two porewate connections for saturation and flushing
• free from tilting with incorporated stainless-steel porous plate
• 2 off Stainless steel porous discs with embedded pin
Adjustable Support Frame
The aim of design and manufacturing of the adjustable support frame is to reduce the sample disturbance as much as possible(This item is not included in standard delivery and ordered separately). The test kit fixes to the base pedestal and then the main part of the kit which is two arms connect to the top cap. Finally, the kit will be assembled to the main machine and after arrangement of the vertical actuator, two arms will be released, and the kit will be di assembled from the machine.
Specimen Preparation Kit
The two-part split former is used to enable rubber membrane to be held tightly against the confining rings when vacuum is applied during sample preparation.
Note: Reinforced membrane with wire-mesh (NGI type) is also available on request.
The set of specimen preparation kit includes of:1 off clamp,1 Set of membrane,1 off Membrane Stretche,1 Set of O-ring,1 Set of filter pape,1 off Two-part split mol,Set of fixing screw
Digital Controller
Digital High-Speed High Resolution Expandable Real Time Control and data acquisition System 10KHz control and data acquisition and 24 bit resolution. The Dynamic controller is suitable for screw driven instruments(electromechanical) , hydraulic instruments with a valve driven with ±10 Volt and variety of sensors e.g. load cells, LVDTs, strain gauges, extensometers, thermocouples and etc.
The multi-functionality of the controller allows a modular design of the measurement and control parameters (sensors) via intelligent sensor plug, which store the calibration parameters, thus depending on the application can be used flexibly.
Main Features
• Up to 32 low-noise closed-loop control channels for static and dynamic tests
• up to 24-bit resolution channels for each test axis (e.g. force, displacement, pressure, strain)
• With digital controller parameterization and bumpless switching between all control functions
• Smooth changeover between all control functions
• Complete, simultaneous data transmission to avoid any data loss
• Digital adjustable controller parameters (P-I-D parameter)
• Simple and flexible test or setpoint parameter adjustment
• I/0 processing of externally connected
• Configuration and setup with PC software