Education

  • Ph.D., University of Michigan, 2003
  • M.S., University of Michigan, 2000
  • M.Sc., École National Supérieure de Techniques Avancées, France, 2000

Research Areas and Descriptors

  • Acoustics and Dynamics; Wave propagation, structural health monitoring, biomechanical systems evaluation, underwater acoustics, and geophysics.

Background

Dr. Sabra began at Tech in 2007 as an Assistant Professor. Prior to this he was a Project Scientist at the Marine Physical Laboratory of the Scripps Institute of Oceanography at the University of California at San Diego.

Dr. Sabra emphasizes an interdisciplinary approach to research problems in different areas (acoustics, structural health monitoring, biomechanics and seismology) based on common wave propagation physics features. His research combines both theoretical and experimental studies for the exploration of these research problems.

Research

(a) Structural Health Monitoring: hydrofoil mounted in an (empty!) water tunnel.(b) Biomechanics: study of muscle stiffness from recordings of (c) Underwater Acoustics: deployment of a parametric source array for buried object detection.

Dr. Sabra's ongoing focus has been the development of novel passive monitoring and imaging techniques based on diffuse wave fields (e.g., ambient noise and multiple scattered fields). Using a combination of laboratory experiments and field data analysis, he has developed noise-based passive imaging and monitoring techniques for dynamic systems (e.g., aircrafts wings or skeletal muscles) and seismoacoustic environments (e.g., oceans or the earth's crust). His techniques rely on low-cost passive sensors without using conventional active probe sources and are thus naturally non-invasive and versatile. His current research projects include: The development of an in-vivo passive elastography technique for soft tissues (e.g., skeletal muscles) using random physiological vibrations self-generated by the human body (e.g., muscles twitches, heart beats); passive structural health monitoring of aircraft wings using flow-induced vibrations and diffuse wavefields; and the use of ambient noise for seismoacoustic tomography of the ocean environment. Dr. Sabra's interests also include the development of environmentally adaptive sonar systems for detection of buried objects in shallow water costal zones for harbor protection and mine counter measures.

In addition to ongoing work in the above mentioned research areas, Dr. Sabra embraces projects that incorporate interdisciplinary studies and collaboration. He believes this type of knowledge exchange can have a great impact on the understanding of wave propagation in random media and provide a foundation for collaboration and technology transfer between academia and industry. Current engineering issues (e.g., in-vivo mechanotransduction or nanosensing systems) typically involve "multi-scale" problems and thus require "multi-wave" tools (e.g., acoustical, electrical, optical).

Tools incorporated in Dr. Sabra's research approach can be widely applied to current engineering problems. Dr. Sabra invests himself in developing both a solid understanding of wave propagation phenomena and physical intuition among graduate students he works with. The theoretical tools and experimental or numerical techniques used in one area (e.g., sound propagation in waveguides) can often be transferred to other areas (e.g., structural health monitoring of mechanical structures). Coupled with his interdisciplinary approach, students gain a global vision that is beneficial in both academic and industrial environments.

Distinctions

  • Acoustical Society of America
  • Institute of Acoustics (Great Britain) A .B. Wood Medal, 2009

Representative Publications

  • A. Duroux, K.G. Sabra, J. Ayers, M. Ruzzene, "Extracting guided waves from cross-correlations of elastic diffuse fields: applications to remote structural health monitoring," J. Acoust. Soc. Am., 122, pp. 204-215 (2010).
  • K. Sabra, H.C. Song, and D. Dowling, "Ray-based blind deconvolution in ocean sound channel," J. Acoust. Soc. Am., 127, EL42-EL47 (2010)
  • K.G. Sabra, A. Archer, "Tomographic elastography imaging of skeletal muscles from their natural vibrations," App. Phys. Lett., 95, L 203701
    (2009)
  • K. G. Sabra, et al. 2005. Surface Wave Tomography using Microseisms in Southern California. AGU Geophysical Research Letters, 32, doi:10.1029/2005GL023155.
  • K. G. Sabra, et al. 2005. Using Ocean Ambient Noise for Array Element Self-localization and Self-synchronization. IEEE Journal of Ocean Engineering 30(2), 338-347.