Accession Number:

ADA224735

Title:

In Situ Fault Detection by the Hybrid Ray Mode Method

Descriptive Note:

Final rept. 1 Sep 1986-28 Feb 1990

Corporate Author:

POLYTECHNIC UNIV BROOKLYN NY

Personal Author(s):

Report Date:

1990-07-09

Pagination or Media Count:

18.0

Abstract:

The objective of this research effort has been to develop algorithms for in situ location and identification, by ultrasound, of flaws in plates or laminated layered elastic materials. Achieving this objective requires detailed knowledge of the excitation, propagation, scattering and detection of high frequency sound waves in the unflawed and flawed environments. Based on an understanding of these fundamental wave phenomena, one may then attempt to construct analytical models with accompanying algorithms, so as to parametrize the NDE problem in terms of good observables. During the contract period, carefully selected prototype problems have been investigated to determine good observables for particular flawed environments. Two major phases have received attention a phenomena within a flat layered plate, especially beam-to-mode conversion, and the consequent interaction with a weak debonding flaw b characterization of transducer outputs in terms of good wave objects that facilitate coupling into and out of the plate environment. The analytical tools rely on spatial and spectral domain formulations, and they comprise self- consistent hybrid beam-mode methods complex source modeling of Gaussian beams, with complex ray tracing to track such beams and decomposition of general wavefields into Gaussian beams. Thus, Gaussian beams, which are good observables are central to the problem strategy.

Subject Categories:

  • Surface Transportation and Equipment
  • Acoustic Detection and Detectors

Distribution Statement:

APPROVED FOR PUBLIC RELEASE