| Composite Vehicle Research Center

Optical equipment

  1. Optical Transmittance Scanner: A custom-built device using a diode laser for quantitative NDI of transparent and translucent materials, particularly certain composites. The depths, extents, and shapes of superimposed internal flaws are obtained with this device and associated custom software.
  2. Short Coherence Length Scanning Interferometer: A custom-built patented device developed in-house for precisely determining the locations and sizes in three-dimensions of small flaws or damages in materials such as transparent armor. It uses a low-coherence diode laser and a path-matching technique.
  3. Digital Image Correlation (2): These devices use digital photographs of a pattern applied to the surface of components to obtain displacement maps in two and three dimensions through a correlation algorithm. Widely used in industry.
  4. Fiber Optic Strain Gages and Interrogators: Both Bragg grating and Fabry-Perot fiber optic strain gage systems for point-wise measurement of strain.
  5. Transmission Photoelasticity: Custom built research-grade polariscopic with adjunct devices for complete whole-field  or point-wise experimental stress analysis of loaded components using a wide variety of wavelengths from deep ultraviolet through far infrared.
  6. Reflection Photoelasticity: Polariscope and adjunct devices for measuring strains at the surface of actual structural members in real-time service conditions. Used widely in the aircraft industry for light weight design enhancement.
  7. Three-dimensional Photoelasticity: Uses the “frozen stress and slicing” technique and a special polariscope to analyze the stresses inside models of loaded structures.
  8. Digital Speckle Pattern Interferometry (DSPI) (4): Otherwise called Electronic Speckle Pattern Interferometry (ESPI), these devices utilize coherent laser speckle patterns to measure with high sensitivity the whole-field displacement and strain maps in loaded components. Also used for NDI of structures such as natural gas fuel tanks.
  9. Electronic Shearography: Uses laser speckle effect for whole field NDI. Widely used in fabrication and repair facilities as well as in the field.
  10. White-light Speckle Photography: Successive high-resolution photographs of the natural surface or subsurface asperities are recorded as the specimen is loaded or moved. These photographs ae then interrogated to obtain displacement information in three dimensions.
  11. Three-axis Moiré interferometry: Uses coherent beam interference to create high-resolution Moiré patterns that facilitate highly sensitive whole-field analysis of displacement and strain.
  12. Projection Moiré: Uses successive digital images of projected line patterns to obtain, mainly, out-of-plane deformations and shape profiles easily and quickly. Similar to the line scanning method used in component fabrication industries, for example, but giving a whole-field picture.
  13. Shadow Moiré: A Moiré pattern is created using the shadow effect, giving in a simple way a direct measurement of topography or change of topography with easily variable sensitivity.
  14. Holographic Interferometry: Creates three-dimensional holographic images that interfere with one another to yield surface displacements. An electronic digital version of this technique is under development.
  15. Components and Devices: A wide variety of optical tables and breadboard components, research-grade cameras, light sources, phase shifters, lenses, filters, beam splitters, mirrors, and so on for creating custom optical systems for measurement applications.
Photo of Gary Cloud demonstrating the optical equipment