Announcement Detail
Tuesday, October 15, 2024
8:00 AM PT
Join via Zoom: https://us06web.zoom.us/j/89805920868?pwd=UaxOZeVHZAs9BeKkjqRWbNadZYCIZo.1
Energy & Earth Systems TTA Webinar
Assessing permafrost demise and infrastructure destabilization using the Arctic Coastal Erosion (ACE) model
Speaker
Dr. Alejandro Mota, Sandia National Laboratories
Abstract
The Arctic holds one-third of the world's coastline and faces rapid, episodic coastal erosion that current permafrost erosion tools fail to fully explain. In this talk, we introduce the Arctic Coastal Erosion (ACE) model, a novel multi-physics finite element framework designed to simulate permafrost degradation in Arctic coastal regions. The ACE model integrates two key components: A solid mechanics model that calculates 3D stress, strain, and displacement in permafrost, using a plasticity model dependent on frozen water content; and an innovative thermal model that governs 3D heat conduction and the solid-liquid phase transitions within the permafrost.
These components are sequentially coupled through a thermo-mechanical scheme, implemented in the open-source Albany/LCM finite element code. This approach allows us to simulate deformation-induced failures, such as block failure, thermo-denudation, and thermo-abrasion, based on constitutive relationships rather than empirical assumptions. To capture transient erosion events, the model dynamically removes elements from the finite element mesh.
The model's capabilities are demonstrated using a pseudo-realistic scenario of a permafrost slice at Drew Point, Alaska, exposed to actual oceanic and atmospheric conditions from July 2018. This cutting-edge model provides new insights into episodic permafrost erosion processes, offering a more comprehensive understanding of these complex phenomena.
Biography
Alejandro Mota is a Principal Member of the Technical Staff in the Mechanics of Materials Department at Sandia National Laboratories in Livermore, CA. He holds a PhD in Structural Engineering with a concentration in Theoretical and Applied Mechanics from Cornell University.
Dr. Mota's career includes the following contributions to computational solid mechanics. At Caltech, he developed and implemented advanced finite element methods to simulate the fracture and fragmentation of brittle and ductile materials, particularly ceramics and metals, under high-speed impact loads. His research extended to constitutive modeling of ductile metals (porous plasticity) and simulations for medical and material applications, including firearm injury to the human cranium, kidney stone fragmentation (lithotripsy) and traumatic brain injury, as well as the fracture mechanics of steel-polyurea composites.
At Sandia National Laboratories, Dr. Mota has focused on regularization methods for finite element simulations and developed constitutive models for damage, failure, fracture, and fragmentation in elastic and inelastic materials under finite deformations. His work also includes implementing variational mapping schemes for field transfer between finite element discretizations and the development of multiscale and multigrid finite element methods based on the Schwarz alternating method. He is actively involved in projects such as Arctic Coastal Erosion (ACE) and Arctic Critical Infrastructure (ACI), contributing to the understanding of climate change impacts in polar regions.
His research interests include multi-physics simulations, computational methods for fracture and damage mechanics, mesh-free methods, GPU computing, and the integration of variational principles in numerical modeling.
Upcoming webinar speakers:
Tuesday, November 12: Prof. Ning Lin, Princeton University
Tuesday, December 17: Prof. Todd Griffith, The University of Texas at Dallas