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Sensors and applications
 

The following information about sensors and application is devided corresponding to the measurement principles: 

1. Video Stroboscopy (visual), 
2. Speckle Interferometry, (ESPI und Shearograph)
3. Correlation Techniques

 

1. Video Stroboscopy

The isi-videostroboscope is a turnkey system for observation and recording of periodical motion up to frequencies of 50 kHz and more. A common application is vibration visualisation by freezing the vibration at a vibration phase of interest or recording a slow motion of the vibration. 
2. Speckle Interferometry (Shearography and ESPI)
Non-destructive testing is the common use of shearography. Sensors and application of shearography are extended to quantitative deformation analysis (vibrations and strains) by isi-sys. 
The Vibrograph is applied for vibration measurements in industry typically in combination with laboratory shakers in harmonic excitation modes using the forced normal mode excitation method.

A small portable piezo-electric shaker also permits local excitation of defects such as cracks, de-laminations and dis-bonds. Vibrating in their natural mode shapes the Vibrograph visualises the defects within the composite structure.
The example shows the evaluated light phase measurement of a de-lamination in C-Si-C composite vibrating at 20kHz. Further software processing yields to amplitude and phase of the object vibrated.

The Vibrograph is also capable of measuring static deformations. The extended configuration for measuring in-plain strains is the Strainograph (left). The modular designs of all isi-sys sensors offers high flexibility for your current problems and future needs.
 

3. Correlation Techniques  (A joint venture of LIMESS and isi-sys)

Digital Image Correlation is an optical method to measure 2D or 3D deformations on an object surface by determination the displacements of gray value patterns in digital images. Some of the advantages of the method are the simple specimen preparation, the insensitivity to vibrations as no lasers are required, the capability to measure large strains (>500%) and the possibility to measure specimen shape and surface displacements in three dimensions. The data evaluation (correlation) and the isi-video-stroboscope can be combined to the  Vibro correlation system for full field vibration measurement (3D amplitudes and 3D strain).

 

For more information about isi-sys products and itīs applications contact us or check our internet pages e. g. for  
 - basic principle of shearography
 - applications in non-destructive testing