User Guide

Mechanical Testing on the UTM

In order to conduct a test the following procedure must be followed:

1. Define and load a test Method into the software
2. Define a Material for your sample
3. Measure and input the Sample information into the software
4. Prepare the machine for the test
5. Load a sample into the UTM machine
6. Conduct the test
7. Review, analyse and export test results

• Appendix 1 - UTM Configuration

Note these instructions assume you have fully commissioned the UTM and calibrated the load cell that is installed.

[SCREENSHOT OF THE FRONT PANEL WITH AREAS LABELLED]

1. Define and load a test Method

Creating a new Method

• The UTM Front Panel allows a user to define a brand new Method from scratch

  • New Method [SCREENSHOT]

• Once a new Method has been defined in the front panel it can be saved to the Method Library for reuse in other tests

Importing an existing Method into the Method Library from a Method file

• Open the Method Library modal window by clicking on the Load From Library button in the Method box - [SCREENSHOT]
• Click on the Import button in the Method Library window.
• Find the open the UTM Method file that you wish to import using the file dialog that opened.
• The file will be then be read into the Method Library so that it can used in a Test

Exporting a UTM Method file

• Methods installed on the UTM can be exported to a JSON file so that it can be used with other UTM machines. By doing this you can share test recipes to replicate functionality and communicate exact test methods with other UTM users around the world.

Load the Method into the current UTM test program

• Open the Method Loader modal window
• Find the Method you want to use
• Click on the Load button on the left hand side of the chosen Method in the table
• Return to the Front Panel to check that the Method has been loaded.

2. Defining and loading Materials

The UTM has its own materials library, which can be accessed via the Materials tab at the top of the front panel.

• Choose from the list of existing materials or create a new one.
• You can search my material name, group or subgroup or just manually filter by group or sub-group.
• If the sample to be tested is made from a material on Materiom Commons, enter the Materiom material ID in the materiom_id box. This will enable it to be linked to the Materiom Commons if you upload your test data later. If a materiom_id is detected on the material a small Materiom Icon will appear next to it in the material library table.
• Load the material into the current test sample by clicking on the Load arrow in the materials table beside the material you want to use

3. Defining and loading Samples

• Define a Sample ID
  • This is a human-readable identification for the physical sample that you are testing. A unique ID is generated for each Test just before it is run but a sample ID helps users visually identify tests when viewing the results. You may have already designated each Sample with an ID when they were made.
  • It helps to write detailed information about the sample in this ID rather than using Sample-01, Sample-02 etc.. However, the Method and Material are both linked to the Test and Sample so it is not necessary to be overly complex i.e. butyl_rubber_tensile_004_10mms_30mm
  • The Sample ID is a searchable field in the Results page once the Test has been completed.
• Define the Material
  • Please see the next section on Materials to learn how to use the materials database to define a material and add it to the Sample. Once a material has been entered into the materials database it is easy to link it to each Sample for future tests.
• Sample gauge Cross Section and measurements.
  • Rectangular
    • A simple, flat gauge length with a rectangular cross-section. Define the gauge length, width (side-to-side) and thickness (front-to-back) as shown in the front panel helper image.
    • You should measure each of the width and thickness at three different locations along its length and take the average of the measurements.
    • Once all the measurements are entered the cross sectional area will be automatically calculated
  • Circular
    • A constant circular cross section along the entire length of the sample. Define the gauge length and diameter.
    • You should measure each of the diameter at three different locations and rotations along its length and take the average of the measurements.
    • Once all the measurements are entered the cross sectional area will be automatically calculated
  • Complex
    • If your sample has a non-uniform cross-section then it is possible to manually enter the cross sectional area instead of individual measurements.
• Once the required Sample information is correct the surrounding border will change to green and you can continue to the next step

4. Prepare the UTM machine for the test

Tensile test

• [VIDEO LINK]
  • Install the correct tensile grips in the UTM, checking that everything in the load stack is tightened to remove any slack
  • Unload the gas struts by moving them to the Unloading position for the current test setup (Current = tensile => move grips together, Current = compression => Move grips fully apart)
  • If gas struts are in the wrong orientation, remove, flip over to the correct direction and reattach to the UTM
  • Move grips fully apart. Stop before any clashes occur.
  • Check that the grips are positioned appropriately for the expected extension in your sample during testing.
  • Preload the gas struts by moving the grips apart a couple of millimetres.
  • You are now ready to insert a sample into the machine grips

Compression test

• [VIDEO LINK]
  • Install the correct compression plates in the UTM, checking that everything in the load stack is tightened to remove any slack
  • Unload the gas struts by moving them to the Unloading position for the current test setup (Current = tensile => move grips together, Current = compression => Move grips fully apart)
  • If gas struts are in the wrong orientation, remove, flip over to the correct direction and reattach to the UTM.
  • Move grips fully apart. Stop before any clashes occur.
  • Check that the grips are positioned appropriately for the expected displacement in your sample during testing.
  • Preload the gas struts by moving the grips together a couple of millimetres.
  • You are now ready to insert a sample into the machine.

5. Loading a physical sample into the machine

The instructions in this section assume that the UTM has already been setup correctly for the type of test. If not, then you should follow the relevant sections of this manual in order to swap toolsets, realign the entire tool chain and re-zero the load cell. To load a sample into the machine, follow the videos below for the relevant test type. There may be some variations to the instructions if you have odd-shaped samples. Test methods that require grips/plates that are not defined in this guide are not supported yet (ie, 3-4 point bend tests)

Tensile test

• [VIDEO LINK]

Compression test

• [VIDEO LINK]

⚠️ PRE- TEST SAFETY CHECKS ⚠️

• Ensure nothing will foul on any moving parts of the UTM during a test. Particularly pay attention to the lower grips clashing with the actuation mechanism or upper grips at the extreme ranges of the test.
• If you suspect your sample is brittle use some form of guard screen to prevent any broken pieces of sample from potentially causing yourself or any bystanders injury. This can happen even with innocuous materials so it is advisable to use a guard at all times anyway.
• Safety glasses are recommended as an absolute minimum for anyone operating or in the local vicinity of a UTM during an active test, even if you do have a safety screen/guard in place.

6. Conducting the Test

6.1 Starting the Test

• Once the test Method, Sample and Material are all properly defined and loaded into the front panel all the boxes on the left hand side of the screen will be bordered with a green outline and a green tick will show in each box title. The Start Test button at the top of the front panel will be also be enabled.
• Pressing the Start Test button will enable the machine motor and start the test procedure according to the test Method. There is a short delay of 1-2 seconds before the motor will begin to move and the test will commence.
• At this stage the Start Test button will change to a red Stop Test button.
• If the Stop Test button is pressed the test will be immediately stopped and the machine motor disabled.
• The test method and sample information will remain loaded so that the test can be repeated if necessary.
• Please take note of whether the sample grips have moved and whether this initial displacement may affect your test results. It it possible to slowly move the grips back to the starting position by using the JOG functionality in the manual controls

6.2 During the Test

During the test, live data for force vs displacement and stress vs strain will be plotted in the plot window of the front panel. These plots can be toggled using the tabs at the top of the plots.

It is also possible to change some basic plot settings during the test.

6.3 End of test

• By default the test will end when the stop condition defined in the Method has been reached.
• It is also possible to manually stop the test before the stop condition is triggered by pressing the Stop Test button at the top of the front panel on the Test tab.

⚠️ SAFETY NOTE ⚠️

At the end of a test the grip positions will remain in the location where they stopped. If the sample has not failed during the test there may be a considerable amount of residual stress pulling on the grips. Check the Load Rel. value at the bottom of the front panel to see if the grips are currently under load. If the Load Rel. value is not close to 0.00 N then it is suggested that the grips are moved manually back to a position where the Load Rel. is reduced as close as possible to 0.00 N. Failure to do this may result in the sample springing out of the grips if they were to be prematurely opened whilst the grips and sample were under load. This is especially true of very elastic samples or specific sample geometries such as springs.

6.4 Repeating multiple tests per session

• Once a Method, Sample and Material has been loaded into a test procedure they will remain loaded after the test has finished. Therefore the same Sample ID will be applied to the next test if the user does not change it. This is intended to help a user test multiple samples quickly without having to reload all the information for each test
• Make sure to check the Sample ID before conducted a test to make sure that it the correct ID is loaded with the physical sample.
• Make sure to remeasure the sample dimensions and update these in the software before conducting another test.

7. Reviewing, Analysing and Exporting Results

7.1 View test results

• Once a test has been completed all of its data is updated and reloaded in the Results page.
• You can search, filter and sort the test data and change the number of tests that are visible in the table by using the tools above the table view.
• To view a test's results, click on the table row and the results will be loaded into the right hand side of the window. You may need to scroll down the screen to view the graphs depending on your screen resolution/size.
• The test summary will be displayed as well as a few charts of the raw data.
• You can compare multiple tests of data my clicking on multiple tests in the table.
• All tests that are currently selected will be highlighted in the table
• To remove a test from the comparison, you can either it's table row again or you can click on the cross next to the sample name show in the tabs at the top-right of the Results page. This will deselect the test and remove its data from the graph plots.

7.2 Analysing test results

There are two methods for analysing the test results.

1. Exporting the raw test data and analysing in external software such as Microsoft Excel, Python, Matlab etc. Analysing the test data externally is not supported by this guide at the as of 03/09/2023 but this may be added by the community at a later date
2. Using the inbuilt UTM analysis capabilities to analyse the test data.

7.2.1 Using UTM test analysis

• In the Results window, select the test that you want to analyse [SCREENSHOT]
• If you have selected multiple tests to compare, make sure that the test you want to analyse is also selected in the tabs on the right hand side of the Results window. [SCREENSHOT]
• Click on the Analyse Test button within the relevant tests result tab [SCREENSHOT]
• There are two categories of analysis that can either be conducted on the load/displacement or stress/strain data.
• Select either the Load vs Displacement or Stress vs Strain graph
• A dropdown selection box will appear allowing you to select the relevant category of result to analyse based on which graph you have selected [SCREENSHOT]
• Click on a data point on the graph to feed the values into the results [VIDEO]
• Automatic analysis of the results has not been provided as it is notoriously unreliable. This method of analysis forces a user to look at the raw data and ensure that the analysis is conducted properly

7.3 Exporting test results to a CSV file

• To export the data from each test, click on the Export icon at the right hand side of the selected test in the Results table.
• By default each exported CSV file is given a default name of {SampleID}_{TestID}.csv so that it can be traced back to the original test data. When exporting you can choose a new filename if you wish as the test and sample data are included in the header lines at the top of the exported CSV file.
• Each test must be exported manually as there is not currently a batch export option (as of software version V1.0.0)
• You can import the test data into a spreadsheet program of your choice (Microsoft Excel, Apple Numbers, Libre Office Calc etc.) in order to view and analyse the raw test data.

Upload test data to Materiom Commons

• Export test data from the Results page of the UTM
• Navigate to the relevant material on the Materiom Commons website. This can be done on the UTM if it is connected to the internet or the csv files can be taken to another device via a USB stick.
• Find the ‘Upload UTM Data’ button and click it to choose a csv file to upload.
• Select the csv file and the data will be automatically read, parsed and uploaded to the Materiom Commons and linked to the material.
• If your test data has not been analysed, the website will show you an error and tell you which values need to be added to the csv file.

THE KEY ANALYSED VALUES ARE: ENTER NAMES HERE

UTM configuration

The UTM installation files comes with a basic configuration file loaded into the database. The configuration is edited via the Settings tab on the front panel. The configuration JSON data is also stored in the configs collection of the utm database of MongoDB and can be edited freely using the mongo command line tool. If any changes are not automatically picked up by the UTM software it should be closed and opened again to ensure that both the Node.js and Python subsystems are reading the correct configuration.

Modules

Controller

• Script ./src/python/controller.py
• Config config.controller

Load Cell

• Script ./src/python/load_cell.py
• Config config.load_cell
• Calibration process

Digital Extensometer

• Script ./src/python/digital_extensometer.py
• Config config.digital_extensometer

Video Extensometer (optional and experimental)

• Script ./src/python/camera.py
• Config - not defined

Data Logger

• Script ./src/python/data_logger.py
• Config config.logger

Machine manual control

• Enable/disable the machine
• Move the actuator/grips - JOG function
• Change JOG speed
• Move the actuator to a known position
• Turn the LED Panels on/off and change brightness

Logs and Alarms

When the UTM is booted up, numerous Python scripts that control subsystems all generate log data. If any function creates and error then it will also be logged. Logs and alarm messages can be viewed directly in the front panel of the UTM by clicking on the Logs tab at the top of the window.