videoXtens 1-32 HP/TZ

The high-temperature specialist for all applications

The videoXtens 1-32 HP/TZ is a non-contact, high-resolution extensometer developed for tests in varied environmental conditions up to 1,400°C.

The videoXtens 1-32 HP/TZ offers a wide range of application:

  • Tests at ambient and high temperatures up to 1,400°C
  • Tests in temperature chambers
  • Long-term applications
  • Cyclic applications (> 2Hz loading frequency)
  • Tensile, compression and flexure tests

videoXtens 1-32 HP/TZ

Typical application videoXtens 1-32 HP/TZ

Metals testing to ISO 6892-2

  • Specific advantages for this application:
  • Strain-rate controlled tests to ISO 6892-2 (high temperature) and to ISO 6892-1 (room temperature) Method A1 (closed loop).
  • Automatic gauge-mark recognition and acquisition of initial gage-length L0.
  • Exact synchronization of all measurement channels.
  • Minimization of environmental influences (e.g. air currents, variations in lighting) through the high temperature tunnel.
  • Optimal and uniform illumination of the specimen with integrated LEDs.
  • Specimens with structured surfaces can be measured via pattern recognition with no need for additional marks.
  • The entire test sequence can be followed on-screen.
  • Video Capturing: specimen recording is synchronized with the measured curve for retrospective viewing of test.
  • Wear-free, and therefore low-maintenance system.
  • Green light and corresponding filters minimize the influence of the glowing specimen.

Glass testing

  • Specific advantages for this application:
  • videoXtens 1-32 HP/TZ is suitable for high-temperature tensile testing on sensitive, as well as transparent specimens such as glass.
  • Sufficient contrast for measurement of transparent specimens through specimen marking with aluminum-oxide powder.
  • No mechanical influence on a soft specimen through optical measuring. Contact extensometers would deform the specimen through the application of sensor arms (lateral force).

Micro specimen testing

  • Specific advantages for this application:
  • Very small initial gauge lengths (from 1.5 mm) are only possible with optical measurement technology.
  • Variable initial gauge lengths with videoXtens 1-32 HP/TZ.
  • Automatic gauge-mark recognition and acquisition of initial gage-length L0.
  • Exact synchronization of all measurement channels.
  • Minimization of environmental influences (e.g. air currents, variations in lighting) through the high temperature tunnel.
  • Optimal and uniform illumination of the specimen with integrated LEDs.
  • Specimens with structured surfaces can be measured via pattern recognition with no need for additional marks.
  • Entire test sequence can be followed on-screen.

Key Advantages and Features

Simple operation

  • Easy to operate
  • Automatic gauge-mark recognition and acquisition of initial gauge-length L0.
  • Tamper-proof: anti-tamper paint is applied to the lenses for the complete system so nothing can be adjusted. An important requirement for reliable test results.
  • Easy alignment to the specimen: videoXtens is centrally aligned to the gauge marks via the connection to the crosshead (option).
  • Compensation for different specimen thicknesses plus testing shear specimens.
  • Wear-free system = low-maintenance. The systems also feature an extremely long service life.
  • Connection to non-ZwickRoell machines via ±10V interface.

High accuracy and repeatability

Automatic centering

  • Automatic centering increases measurement travel and measuring accuracy.
  • laserXtens tracks at half crosshead speed via the connection to the crosshead, keeping the testing operation automatically in focus and making optimum use of the measuring range.
  • This results in increased system accuracy; the gauge marks shift less in the image and are captured in the (more accurate) center of the lens.

Testing without gauge marks

  • Pattern recognition: testing with software gauge marks
  • The innovative pattern-recognition algorithm allows virtual gauge marks to be applied to the specimen. The gauge marks can be changed retrospectively and re-calculated (Test Re-Run option). It doesn't get any more convenient!
  • The essential requirement is for a pattern on the specimen - either a natural pattern due to a structured surface or an artificial pattern which can quickly be applied using a marker spray or by stippling.

Technical Data

Type

videoXtens 1-32 HP/TZ

Initial gauge length

1.5 … 32

mm

Measurement displacement

For fixed assembly

32 mm - initial gauge length

For automatic entrainment

2 * (32 - initial gauge length)

Resolution

0.25

µm

Accuracy class to EN ISO 9513

0.5

Temperature range

-150°C ... +1,400°C

Measurement frequency for standard setup

70

Hz

Measurement speed, max. at measurement point

500

mm/min

Scope of delivery

Measuring head with one digital camera incl. high resolution telecentric lens, interference filter, green LED incident light lamp, high temperature tunnel for reduction of environmental influences, software for image acquisition, accessory case with scaling aid, INC module (for tC: RS module). Incl. connection to crosshead; the extensometer tracks at half test speed.

Software Options 

testXpert III testing software offers various options for precise, traceable non-contact extension and strain distribution measurement. 

Test re-run

The optional Test ReRun module enables subsequent recalculation of strain on the basis of an image series recorded during a test, using a different initial gauge-length (provided multiple markings are present). This can be particularly advantageous in component testing, for example, when it is necessary to evaluate local strain at different locations, or in standard tensile tests when specimen necking has occurred outside the original initial gauge-length.

Automatic symmetrical adjustment of strain around necking to ISO 6892-1, Annex I

The recalculated strain can, of course, be synchronized subsequently with the other measurement values via the testXpert testing software.

Strain distribution

The Strain Distribution option enables determination of local strains at multiple measuring locations along the specimen gauge-length. These are available as channels in testXpert. Up to 16 measuring locations are automatically recognized and evaluated during the test. This option also allows automatic real-time symmetrical adjustment of the initial gauge-length around the necking (to ISO 6892-1, Annex I).

Video Capturing

Video capture is a recording of the test (without retrospective recalcualation). The recording is synchronized with the measured curve, enabling the test to be viewed retrospectively. The option includes no hardware, as recording and synchronization take place entirely via the videoXtens system.

2D dot matrix

This option allows two-dimensional measurement of dots applied to a planar specimen surface. This enables determination of local strains and specimen inhomogeneities under load. X and Y coordinates, as well as the distances between dots, are available as measured values.

Up to 100 measurement dots can be measured in any desired arrangement or in matrix form. Display in testXpert III is limited to 15 channels.

This option uses only one camera for measurement; any other cameras present are switched off beforehand.

Second measurement axis option 

With this option, biaxial measurements can be performed: In addition to the longitudinal strain, transverse strains can also be recorded—for example the change in width. Alternatively, change in width can of course also be measured alone.

  • Two versions are available for measurement of transverse strain:
  • Direct measurement on the specimen edge without additional markings (required for the determination of the r-value). For this version a backlight is required.
  • Measurement of the specimen surface with dot markings or sprayed-on pattern. For this version the specimen is illuminated with an incident light lamp.

Deflection measurement 

videoXtens can also be used for flexure tests. There are several options for measuring specimen deflection, depending on the type of test and the specimen condition and properties:

  • Measurement using incident light via marks on the specimen
  • Measurement using backlight on the specimen lower edge
  • Measurement of deflection in the test axis or of the polynomial approximation of the curve

Maximum deflection that can be measured: with videoXtens the maximum deflection corresponds to the FOV; with videoXtens Array to 1/3 of the total FOV (in this case deflection is measured with one camera only).

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