Initial studies on the use of laser velocimetry in the inspection and health monitoring of aircraft
- Sandia National Labs., Albuquerque, NM (United States)
- Holographics Inc., Long Island City, NY (United States)
During routine inspections of commercial aircraft, various forms of surface corrosion, or other surface defects, are often encountered. However, it is difficult to assess the need for structural repair without a complete knowledge of the corresponding damage to the subsurface structure. Therefore, it is important for inspection techniques to be able to quickly assess the health of a structure, including subsurface damage, with only access to the external inspection surface. Modal and structural dynamics measurements hold promise for the global non-destructive inspection of a variety of structures including aircraft. Surface measurements of a vibrating structure can provide information about the internal members without costly - or sometimes impossible - dismantling of the object. However, there are limitations with the traditional measurement techniques for these parameters (modal frequencies, modal damping, mode shapes, and frequency response functions). Modal testing techniques can cover a broad frequency band and have a large array of mathematical tools for signal processing and data analyses. Modal testing is normally characterized by contact sensors, low spatial density, and low frequencies (less than 1 kHz). These limitations severely restrict the ability of modal techniques to locate the type of damage seen in aircraft. Full-field techniques, such as laser holographic interferometry, provide high frequency, high spatial density measurements in a non-contact fashion. However, laser imaging techniques like holographic interferometry operate on a single vibration frequency at a time, and do not have the same level of mathematical processing support as modal techniques. Laser velocimetry provides a {open_quotes}best of both worlds{close_quotes} approach with some additional advantages not found in either modal or coherent optics techniques.
- Research Organization:
- Sandia National Labs., Albuquerque, NM (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States); Federal Aviation Administration, Washington, DC (United States)
- DOE Contract Number:
- AC04-94AL85000
- OSTI ID:
- 10183855
- Report Number(s):
- SAND-94-1161C; CONF-9403160-1; ON: DE94019194; TRN: 94:008813
- Resource Relation:
- Conference: 21. annual review of progress in quantitative nondestructive evaluation,Snowmass, CO (United States),2 Mar 1994; Other Information: PBD: [1994]
- Country of Publication:
- United States
- Language:
- English
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