Using Clisp Studio part 4
Using Clisp Studio Part 4 – Frame and Sensor Corrections
These ‘Using Clisp Studio’ posts are intended to highlight facilities in Clisp Studio that the User may not be aware of, or general facilities to help
testing run smoothly.
Some Equipment may require corrections to allow for the deformation of the frame due to heavy use over time or other corrections due to prolonged stresses
and strains. Click on the ‘Equipment’ button and then select ‘Add’ from the pop-up menu, to add the Equipment requiring correction as shown below.
Corrections can be applied to Oedometers (Frame corrections), Rowe Cells (Diaphragm Corrections), Permeability Cells (Head Loss Corrections), Shearboxes
(Axial and Shear Corrections) and Unsaturated Triaxial Test Systems (Pressure/Volume correction). This involves setting up a table of corrections to be
applied in Clisp Studio.
In the following examples, Oedometer Frame and Shearbox Corrections will be demonstrated.
From the ‘Consolidation Apparatus’ pull-down menu, select ‘Oedometer Frame’ as shown and then click ‘Ok’.
The resultant screen allows the user to input load correction data into the table, which is necessary to add to the cumulative vertical settlement of the
specimen to allow for the deformation of the frame under each load increment. The following picture gives an example.
The measured axial displacements during consolidation and shear need to be corrected for apparatus compressibility.
From the ‘Stress and Strength Apparatus’ pull-down menu, select ‘Shear Box’ as shown and then click ‘Ok’.
Axial corrections are measured using a Calibration disc, applying a series of incremental loads and recording the displacement.
Shear corrections allow for the resistance of the lateral confinement and are measured by applying the shear displacement and measuring the shear force as
the top platen is displaced relative to the bottom platen.
Examples are shown below. Once input, the values will automatically be applied by the relevant Clisp Studio test module.
Selection of the ‘Inputs’ tab of the main Instrument control panel brings up the list of connected sensors. Selection of the Channel Number from the
‘Inputs’ tab will display the data associated with the selected sensor.
In the example shown below, the ‘Load’ channel has been selected. Selection of the ‘Linearisation’ tab enables input of measured values at particular
points to allow for any slight variations in a sensor.
Input a sample of values that the Transducer should be reading into the ‘Expected’ column of the table and then input the value the Transducer actually
reads into the ‘Measured’ column.
When working with the Linearisation table the following view options are available:
– Simply erases the table, both Expected and Measured columns. The Expected column is also split into 10 equally spaced intervals covering the complete
range from Zero to Full Scale (as entered in the Scaling Details shown in the previous section).
Enters the current Transducer reading into the measured column at the selected row.
Gives a choice of what elements to display:
- Both displays the table and graph views of the linearisation data
- Table displays only the table, and
- Graph displays only the graph.
The Linearisation values will then be automatically applied by the relevant Clisp Studio test module to the sensor.