TODAY: Lars Hansen, 14-Oct-23, 12:20pm Central
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Ellad Tadmor
Nov 14, 2023, 4:16:45 AM11/14/23
to aem-solid...@umn.edu
AEM Mechanics Research Seminar
Tuesday 14-Oct-2023, 12:20pm Central
Prof. Lars Hansen
Department of Earth and Environmental Sciences, University of Minnesota
Title: From mega-annum to microseconds: the role of crystal dislocations in the dynamics of the solid earth
Abstract: Large-scale geodynamic processes in the solid Earth often depend intimately on small-scale defects within the constituent minerals. These processes span a wide range of time scales and include convection in the upper mantle, flexure of the lithosphere, glacial isostatic adjustment, postseismic creep, and frictional sliding on faults during earthquakes. Here I describe the influence of dislocations, a particular type of crystal defect, on this range of processes within upper-mantle rocks. The role of dislocations across these timescales is elucidated by a series of laboratory experiments including synchrotron-based experiments to measure yield stress and strain hardening, high-temperature uniaxial tests to investigate anelasticity, and dynamic indentation using ball-drop experiments to assess mineral strength at extreme strain rates. These different experimental approaches are linked through the dynamics of dislocations. The resulting model of dislocation-based deformation resolves conflicts among previous geophysical observations and provides a series of new predictions about the mechanical properties of rocks at both slow and fast timescales not typically accessible in the laboratory.
For more information, visit the AEM Mechanics Research Seminar website:
Tuesday 14-Oct-2023, 12:20pm Central
In-person: Room 402, Walter Library, University of Minnesota
Online: Webinar registration link
Department of Earth and Environmental Sciences, University of Minnesota
Title: From mega-annum to microseconds: the role of crystal dislocations in the dynamics of the solid earth
Abstract: Large-scale geodynamic processes in the solid Earth often depend intimately on small-scale defects within the constituent minerals. These processes span a wide range of time scales and include convection in the upper mantle, flexure of the lithosphere, glacial isostatic adjustment, postseismic creep, and frictional sliding on faults during earthquakes. Here I describe the influence of dislocations, a particular type of crystal defect, on this range of processes within upper-mantle rocks. The role of dislocations across these timescales is elucidated by a series of laboratory experiments including synchrotron-based experiments to measure yield stress and strain hardening, high-temperature uniaxial tests to investigate anelasticity, and dynamic indentation using ball-drop experiments to assess mineral strength at extreme strain rates. These different experimental approaches are linked through the dynamics of dislocations. The resulting model of dislocation-based deformation resolves conflicts among previous geophysical observations and provides a series of new predictions about the mechanical properties of rocks at both slow and fast timescales not typically accessible in the laboratory.
For more information, visit the AEM Mechanics Research Seminar website:
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Ellad B. Tadmor, Ph.D.
Russell J. Penrose Professor
Department of Aerospace Engineering and Mechanics
University of Minnesota
https://dept.aem.umn.edu/~tadmor/
Russell J. Penrose Professor
Department of Aerospace Engineering and Mechanics
University of Minnesota
https://dept.aem.umn.edu/~tadmor/
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