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This content will become publicly available on November 15, 2018

Title: Propagation and dispersion of shock waves in magnetoelastic materials

Previous studies examining the response of magnetoelastic materials to shock waves have predominantly focused on applications involving pulsed power generation, with limited attention given to the actual wave propagation characteristics. This study provides detailed magnetic and mechanical measurements of magnetoelastic shock wave propagation and dispersion. Laser generated rarefacted shock waves exceeding 3 GPa with rise times of 10 ns were introduced to samples of the magnetoelastic material Galfenol. The resulting mechanical measurements reveal the evolution of the shock into a compressive acoustic front with lateral release waves. Importantly, the wave continues to disperse even after it has decayed into an acoustic wave, due in large part to magnetoelastic coupling. The magnetic data reveal predominantly shear wave mediated magnetoelastic coupling, and were also used to noninvasively measure the wave speed. The external magnetic field controlled a 30% increase in wave propagation speed, attributed to a 70% increase in average stiffness. Lastly, magnetic signals propagating along the sample over 20× faster than the mechanical wave were measured, indicating these materials can act as passive antennas that transmit information in response to mechanical stimuli.
Authors:
ORCiD logo [1] ; ORCiD logo [2] ;  [3] ;  [3]
  1. Univ. of California, Los Angeles, CA (United States). Dept. of Mechanical and Aerospace Engineering; Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Physics Division
  2. Univ. of California, Los Angeles, CA (United States). Dept. of Mechanical and Aerospace Engineering; Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States). Dept. of Biomedical Engineering and Mechanics
  3. Univ. of California, Los Angeles, CA (United States). Dept. of Mechanical and Aerospace Engineering
Publication Date:
Report Number(s):
LLNL-JRNL-731703
Journal ID: ISSN 0964-1726
Grant/Contract Number:
AC52-07NA27344
Type:
Accepted Manuscript
Journal Name:
Smart Materials and Structures
Additional Journal Information:
Journal Volume: 26; Journal Issue: 12; Journal ID: ISSN 0964-1726
Publisher:
IOP Publishing
Research Org:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; 36 MATERIALS SCIENCE; magnetoelastic; laser shock; Galfenol; ferromagnetic; high strain rate; wave propagation; wave coupling
OSTI Identifier:
1418915