Multiscale Mechanics of Materials: From Atoms to Planets

Aerospace Colloquium
Department of Aerospace Engineering
Indian Institute of Science, Bangalore
Multiscale Mechanics of Materials: From Atoms to Planets 

Vinamra Agrawal Department of Aerospace Engineering at Auburn UniversityWednesday,

08th January, 2020, 4.00 PM

Auditorium, Department of Aerospace Engineering, IISc, Bangalore

Material response at a given length scale is intrinsically linked to its properties at the lower length scales. For instance, a process such as impact cratering, that spans tens or hundreds of kilometers is linked to how individual atoms within the target interact with each other. In this talk we will focus on four length scales, kilometers, centimeters, micrometers and nanometers.

At the kilometer scale, we will study the problem of shallow marine impact craters focusing on the Wetumpka impact crater. We will use iSALE-2D, an ALE based hydrocode, to model impact on a layered target submerged in a shallow layer of water. We study the evolution of the transient crater, followed by processes such as rim collapse and tsunami resurge. At the centimeter scale, we will use experiments to characterize materials obtained from drill cores and field studies at Wetumpka. We conduct compression tests, and splitBrazilian tests to characterize samples for the hydrocode tests. At the micrometer scale, we will focus on grain boundary evolution and micro crack formation. We will use a novel computational scheme (Alamo) that solves phase field and elasticity equations on a block structured adaptively refined grid. Using Alamo, we will model grain boundary evolution with anisotropic grain boundary energy. Finally at the nanometer scale, we will talk about capturing shock waves through concurrent atomistic continuum scheme. We will discuss a new control volume based concurrent atomistic continuum scheme that follows shock wave as it propagates through the material. Using this scheme we study steady state shock wave propagation and shock kinetics.

Vinamra Agrawal is an Assistant Professor in the Department of Aerospace Engineering at Auburn University with an adjunct appointment in the Department of Geosciences at Auburn University. He received his PhD in Mechanical Engineering from Catech in 2016, MS from Caltech in 2012 and BTech from IIT Kanpur in 2011. Prior to joining Auburn in Jan 2017, he was a postdoctoral scholar at Jet Propulsion Laboratory (JPL) and Caltech. His work involves understanding material response through experimental and computational methods. His primary interest is towards understanding material response under extreme loading, such as shock loading and fatigue. His lab focuses on additively manufactured metals, geological materials and polymer-matrix composites.

All are welcome

Date/Time
Date(s) - 08/01/2020
4:00 pm - 5:15 pm

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