Standard Article

Nonlinear Acoustic Methods

Physical Monitoring Principles

Passive and Active Measurements with Data Analysis Approaches for Load and Damage Identification

  1. Dimitri M. Donskoy

Published Online: 15 SEP 2009

DOI: 10.1002/9780470061626.shm014

Encyclopedia of Structural Health Monitoring

Encyclopedia of Structural Health Monitoring

How to Cite

Donskoy, D. M. 2009. Nonlinear Acoustic Methods. Encyclopedia of Structural Health Monitoring. .

Author Information

  1. Stevens Institute of Technology, Hoboken, NJ, USA

Publication History

  1. Published Online: 15 SEP 2009

Abstract

The nonlinear acoustic technique (NAT) developed for detecting and characterizing structural and material defects is an emerging field with unique advantages and challenges. NAT exploits nonlinear dynamic behavior produced by contact interfaces and micro- and mesoscopic inhomogeneities associated with structural defects and damages including cracks, disbonds, and delaminations. Nonlinearities across the defects lead to noticeable nonlinear transformations of the interrogating acoustic signals such as harmonic distortions, frequency mixing, modulations, etc. Digital signal processing is used to experimentally capture these transformations unlocking the potential of the NAT to monitor and characterize nonlinear defects and damages in a wide variety of materials and structures.

Keywords:

  • nonlinear acoustics;
  • contact nonlinearity;
  • defect detection;
  • damage monitoring;
  • acoustic wave interaction;
  • harmonic distortion;
  • vibroacoustic modulation