Zwick has released its latest VideoXtens video extensometer aimed at materials testing applications where it is impractical or inadvisable to make contact with the specimen
Able to simultaneously measure longitudinal as well as transverse strain the device is particularly suited for the measurement of R and N values to ISO 10113 and ISO 10275 respectively on sheet steel as well as in many other applications where a contact extensometer could be damaged by whiplash from a fracturing specimen, such as the testing of belts.
All strain related test results such as offset yield/proof stress, yield point elongation, R value, and strain to failure are measured automatically.
For the measurement of the reduction in width of the specimen during the test the extensometer uses sophisticated edge detection technology which saves time by avoiding the need for the operator to attach a second pair of marks to the sample.
The video extensometer is attached to the test machine frame using a secure yet flexible mounting unit which ensures perfect alignment with the axis of the testing machine, and the specimen being tested.
For testing machines having two test areas the universal extensometer mounting system can be simply adapted to either area, whilst the versatile specimen illumination system can also be placed in the optimum position for each test.
Using the extensometer with the testing machine is simplicity itself.
After a one time setup procedure the operator simply attaches two marks on the test specimen, places it in the grips of the tester and starts the test.
The extensometer is able to measure the distance between the marks and can use this value as the gauge length for the test.
Zwick's proprietary software TestXpert, is used to control, synchronize, and process the longitudinal strain, transverse strain and force data in real time on a single PC.
When carrying out tests in a temperature chamber the extensometer can remain at ambient temperature and view the specimen marks through a glass window.
This eliminates the need to contact the specimen, improves the accuracy of test results, and simplifies the test procedure.
The Zwick videoXtens is available with a choice of four fields of view (FOV) to suit different applications.
With a field of view of 50mm the system has a resolution of 0.25um, and the video extensometer complies with Class 1 of ISO 9513, and B2 of ASTM E83.
An optional software tool records a real-time video stream of the test which can then be used as part of the test documentation, or as a visual aid for education or training purposes.
