Vibrothermography

UTvis - advantage with large complex components

  • Vibrothermography is a defect-selective test method
  • Ideally suited for crack detection on complex specimen

Vibrothermography

Ultrasound thermography (or vibro-thermography) is a powerful test method for defect selective indication of cracks, disbonds, or delaminations. UTvis test stands are based on digital high-power ultrasound generators and converters as excitation sources and high-sensitive infrared cameras. A temperature resolution of 16 mK and frame rates up to 400 Hz (full frame mode) in lockin or burst mode enables to detect smallest dissipative effects and allow for a reliable flaw detection with minimum of mechanical load for the component.

Principle of Vibrothermography

Vibrothermography

Ultrasound Thermography (or Vibrothermography) uses the interaction of mechanical and thermal waves to detect material defects. If a defect in a component absorbs the injected, high-energetic ultrasound waves, it will locally heat up (defect selective dark-field method). The resulting temperature gradient on the specimen surface is measured by an infrared camera, visualizing the dissipated energy. Depending on the application, there are two derivatives of this method: the very fast burst phase analysis and the sensitive Lockin method. In both cases the evaluation calculates the time delay between injected energy and the thermal response, resulting in a robust and reliable technique, which is invariant against surface properties or ultrasound distribution.

Typical applications for Vibrothermography

Crack detection in aluminium casted component

Crack in casted component. Left to right: Photo, Heat dissipation due to vibro-excitation, Lockin-evaluation, Lockin evaluation with threshold filter.

Applications

  • Crack detection (open as well as closed cracks, independent of their orientation in the material)
  • Testing of adhesive, rivet, and welding joints
  • Characterization of multi-material compounds
  • Detection of delamination and impacts in fibre composite material

UTvis Software

  • DisplayImg Basic / Professional

    Extensive acquisition and evaluation software with leading concept such as project-tree and script-interface, dedicated for UTvis measurements. Numerous extension modules are available

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Specification

Sound generation UTvis 4000
Output power 4 kW
Supply 400V / 16A
Frequency modulation 15 kHz - 25 kHz
Overload protection yes
Housing 19'' / 3U