Characterizing plastics and composites under temperature can be challenging. Their performance becomes less predictable and reliable in applications where they are pushed to the ends of their service temperature range. Furthermore, they become harder and less flexible in low-temperature environments and can become either softer or too rigid in high temperature environments.
“The right test setup is critical for testing plastics and composites,” explains Dr. Mehdi Dargahi, Regional Sales Manager for Canada at ZwickRoell in North America. “Many companies and universities looking for a solution are initially not aware of how important it is to use a high-performance video extensometer that can be completely integrated in a well-engineered temperature chamber. The right equipment can greatly improve measurement accuracy and reliability of the test results.”
What are the factors that play a role in reliable test results when characterizing plastics and composites?
- The temperature chamber must allow for flawless integration of the extensometer without affecting the measurement accuracy and resolution of the extensometer. ZwickRoell’s sophisticated air-feed system ensures extremely uniform temperature distribution and air flow throughout the entire chamber, with only ±1 °C of temperature fluctuation within the entire testing area. This guarantees the highest measurement resolution and class accuracy when ZwickRoell extensometers are used with the temperature chamber.
- The extensometer must be mounted in such a way that it has an unobstructed view into the test area. ZwickRoell’s videoXtens extensometer is mounted at the side of the chamber, offering a significant advantage over test setups where the extensometer is installed in front of the door and must be moved each time the chamber is opened. In these cases, front mounting of the extensometer results in a constantly changing field of view (FOV), which leads to measurement inaccuracies and possibly even damage to the equipment. In contrast, ZwickRoell’s extensometers follow the specimen at half crosshead speed via the connection to the crosshead, keeping the testing operation automatically in focus, offering the best FOV and making optimum use of the measuring range.
- The extensometer must have a high accuracy class and resolution at different testing temperatures. Testing per standards such as ISO 527-1 requires a high resolution (e.g. <1 µm) for strain measurement. ZwickRoell’s extensometers, such as videoXtens 2-120 HP, are among the only extensometers that fully comply with such requirements and offer a unique resolution of 0.4µm at +250 °C, producing significantly more accurate test results compared to conventional video extensometers with a poor resolution of 5µm or below.
When paired with ZwickRoell’s temperature chamber, videoXtens is an excellent choice for composites and plastics testing requiring a level of accuracy that cannot be achieved by any other non-contact extensometer. Testing under temperature with both typical and challenging specimens does not have to be difficult with the right test equipment. For more information, visit our website or read our Product Information on ZwickRoell’s temperature chamber and videoXtens.