The requirements for precise testing technology are increasing with the variety of new materials and complex manufacturing processes. With VideoXtens, ZwickRoell offers a non-contact optical extensometer that enables versatile and accurate strain measurements – from classic tensile tests to tests under extreme conditions.
For tensile tests to ISO 6892-1, ASTM E8 or ISO 527-1, VideoXtens records changes in length optically, without physical gauge marks. The natural surface structure of the specimen is made visible by blue contrast light, which saves time and reduces measurement errors. Automatic measurement field placement in the expected break area optimizes the process, especially in test series. The high image resolution enables the detection of the smallest strains with micrometer accuracy. The accuracy is verified from as little as 10 µm during on-site calibration and confirmed by a certificate.
Determination of r- and n-values for forming technology
In sheet metal forming, the r-value (anisotropy ratio) and the n-value (strain hardening exponent) are key material parameters. With VideoXtens, these can be determined in accordance with ISO 10113 and ISO 10275 without manual specimen marking. Simultaneous acquisition of longitudinal and transverse strain provides precise values, even with short specimen lengths or highly reflective surfaces. The automated measurement increases the testing speed and guarantees reproducible results – crucial in the series production of car body or structural parts.
Automated fracture strain measurement
VideoXtens offers automatic fracture detection for determining elongation at break in accordance with ISO 6892-1 Method B or ISO 527-1. The system tracks the gauge marks throughout the test and automatically detects the break. This eliminates manual measurement of specimen ends and reduces error-prone reworking – an advantage in automated testing environments with high throughput rates.
Precision in dynamic tests
VideoXtens is able to record dynamic tests at high strain rates with a high frame rate. The strain is recorded synchronously with the force measurement – essential for evaluating crash behavior or determining viscoelastic effects. Cyclic tests, such as those used in material fatigue, can also be precisely documented with the system. The repeatability remains consistently high even with rapidly changing strain curves.
Digital image correlation for local strain distributions
The addition of digital image correlation (DIC) gives VideoXtens additional analytical depth. Not only are total changes in length measured, but areal strain distributions are also analyzed in real time. This is particularly relevant for anisotropic materials such as fiber composites or 3D-printed components. The identification of local weak points, material inhomogeneities or strain maxima enables a detailed assessment of component behavior under load.
Versatile application possibilities
VideoXtens offers precise, non-contact measurements for demanding applications. Whether at extreme temperatures from -55 °C to +360 °C, in medical technology for microcomponents such as stents and catheters or in electromobility for sensitive materials such as separator foils – the system delivers reliable results without affecting the specimen. Seamless integration into the TestXpert testing software enables efficient data acquisition and evaluation.
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