Can Reliant extensometers be left on through specimen failure?
Yes, Reliant extensometers are designed for use through specimen failure. However, testing hard / high strength materials will cause knife edges to wear out faster. A spare set of knife edges is included with each unit, but knife edges should be inspected regularly and spare sets may be needed. One way limit wear-and-tear to your extensometer is as follows: Using a lower measuring range extensometer (5 to 20 % strain), run your test until a certain strain is reached, pause the test, remove the extensometer, and resume the test using the actuator or crosshead travel to obtain the rest of the test data to specimen failure. This procedure allows approximate measurement of elongation to failure (the data at elongation to failure is not normally critical). Using this procedure will reduce the amount of wear and chance of damage to your extensometer’s knife edges. However, not all test controls allow you to pause a test; please check your system’s capability.
