TODAY: Suraj Ravindran, 17-Jan-23, 12:20pm Central

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Ellad Tadmor

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Jan 17, 2023, 8:35:20 AM1/17/23
to aem-solid...@umn.edu
AEM Mechanics Research Seminar

TODAY, Tuesday 17-Jan-2023, 12:20pm Central
 
Prof. Suraj Ravindran
Department of Aerospace Engineering and Mechanics, University of Minnesota

Title: Mesoscale shock structure in particulate composites

Abstract: Multiscale experiments in heterogeneous materials and the knowledge of their physics under shock compression are limited. This study examines the multiscale shock response of particulate composites comprised of soda-lime glass particles in a PMMA matrix using the newly developed full-field high-speed digital image correlation (DIC) for the first time. The high spatial resolution measurement using high speed digital image correlation allowed to measure the spatially resolved velocity profile. Normal plate impact experiments, and complementary numerical simulations, are conducted at stresses ranging from 1.1 − 3.1 GPa to elucidate the mesoscale mechanisms responsible for the distinct shock structure observed in particulate composites. The particle velocity from the macroscopic measurement at continuum scale shows a relatively smooth velocity profile, with shock thickness decreasing with an increase in shock stress, and the composite exhibits strain rate scaling as the second power of the shock stress. In contrast, the mesoscopic response was highly heterogeneous, which led to a rough shock front and the formation of a train of weak shocks traveling at different velocities. Additionally, the normal shock was seen to diffuse the momentum in the transverse direction, affecting the shock rise and the rounding-off observed at the continuum scale measurements. The numerical simulations indicate that the reflections at the interfaces, wave scattering, and interference of these reflected waves are the primary mechanisms for the observed rough shock fronts.

For more information, visit the AEM Mechanics Research Seminar website:




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Ellad B. Tadmor, Professor

Department of Aerospace Engineering and Mechanics
University of Minnesota
107 Akerman Hall, 110 Union St SE
Minneapolis, MN 55455, USA

tel:   612-625-6642
fax:   612-626-1558
web:   Tadmor Website |
Modeling Materials Book Website
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