Article
Computer Science, Interdisciplinary Applications
Octavio Castillo-Reyes, David Modesto, Pilar Queralt, Alex Marcuello, Juanjo Ledo, Adrian Amor-Martin, Josep de la Puente, Luis Emilio Garcia-Castillo
Summary: This paper presents a routine for 3D magnetotelluric (MT) modeling using high-order edge finite element method (HEFEM), tailored and unstructured tetrahedral meshes, and high-performance computing (HPC). The accuracy, robustness, and performance of the code are evaluated using reference models developed by the MT community. The results show that the new algorithm can generate expected solutions for 3D MT models and provide insights on the effectiveness of high-order discretizations, tailored mesh design, and the use of HEFEM, tailored meshes, and HPC for solving realistic and complex 3D MT models.
COMPUTERS & GEOSCIENCES
(2022)
Article
Computer Science, Interdisciplinary Applications
Ce Qin, Xuben Wang, Ning Zhao
Summary: This paper presents an open-source parallel 3D forward modeling code called EMFEM for the frequency-domain electromagnetic method (FDEM). The code is based on the adaptive finite element method and utilizes tetrahedral meshes to handle complex geometry and topography. It includes an iterative solver, optimal block-diagonal preconditioner, and adaptive mesh refinement to improve accuracy. The code is implemented in C++ and can be used for large-scale 3D problems on high-performance computing platforms.
COMPUTERS & GEOSCIENCES
(2023)
Article
Geosciences, Multidisciplinary
Kailiang Lu, Jianmei Zhou, Xiu Li, Ya'nan Fan, Zhipeng Qi, Huake Cao
Summary: In this paper, the combination of the Shift-and-Invert Krylov (SAI-Krylov) subspace method and the preconditioned conjugate gradient method (PCG) is used to solve the problem of 3D large-scale time-domain transient electromagnetic (TEM) forward modeling. The optimal shift gamma(opt) is selected based on the relationship between the condition number of the coefficient matrix and shift gamma to improve the computation efficiency. The validity and applicability of the proposed method are verified through various models.
JOURNAL OF APPLIED GEOPHYSICS
(2022)
Article
Computer Science, Software Engineering
Thomas C. Clevenger, Timo Heister, Guido Kanschat, Martin Kronbichler
Summary: The paper introduces a geometric multigrid method for massively parallel computations on adaptively refined meshes, utilizing local smoothing and partitioning through a space filling curve. Efficiency of mesh hierarchy distribution is modeled and compared to runtime measurements. The algorithm is implemented in the DEAL.II finite-element library for public use.
ACM TRANSACTIONS ON MATHEMATICAL SOFTWARE
(2021)
Article
Geochemistry & Geophysics
Changkai Qiu, Changchun Yin, Yunhe Liu, Xiuyan Ren, Hui Chen, Tingjie Yan
Summary: This study discusses the challenges in inversion of geophysical survey data for complex 3D structures and presents the development of efficient and robust iterative solvers to address these challenges. By transforming the linear system into real-number format and introducing optimal block-diagonal preconditioners, the study achieves fast solution convergence for frequency-domain CSEM modeling problems.
Article
Engineering, Mechanical
Lei Xu, Lei Jiang, Lei Shen, Lei Gan, Yijia Dong, Chao Su
Summary: This work presents an adaptive hierarchical multiscale approach for modeling the trans-scale damage evolution in concrete. The approach can track and quantify the damage evolution in concrete by decomposing the problem domain into macroscopic elastic region and multiscale critical region.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2023)
Article
Mathematics, Applied
Nagaiah Chamakuri, Philipp Kuegler
Summary: In this paper, a method combining space-time adaptive discretization with dynamic load balancing for parallel computing is proposed to solve the challenging computational problem in cardiac electrophysiology. The method utilizes multilevel finite element methods for spatial adaptation, embedded Rosenbrock time integration for adaptive step size selection, and non-overlapping domain decomposition for parallelization. It also takes advantage of the sparsity of local matrices to optimize memory usage. Numerical tests demonstrate the feasibility of the approach, achieving a substantial reduction in computing time and good parallel efficiency.
APPLIED NUMERICAL MATHEMATICS
(2022)
Article
Construction & Building Technology
Totsawat Daungwilailuk, Phoonsak Pheinsusom, Withit Pansuk
Summary: This study focuses on the design of load-bearing walls in 3D-printed buildings, conducting experiments on different wall samples and finite-element analysis to evaluate the behavior of the walls. Results show that the flat wall with an inner truss outperformed the diamond wall, providing a new perspective on design flexibility.
CONSTRUCTION AND BUILDING MATERIALS
(2021)
Article
Environmental Sciences
Fei Wang, Hongchun Zhu, Haolin Cai, Wenhu Qu, Shuaizhe Zhang, Zhendong Liu
Summary: This paper proposes a parallel method for texture reconstruction in large-scale 3D automatic modeling, which calculates the hierarchical relationships between the texture reconstructions and selects the best-view label using the graph-cut algorithm, effectively addressing the issues of high memory consumption and difficulties in large-area texture reconstruction in existing methods.
Article
Mathematics, Interdisciplinary Applications
Carlos A. Moreira, Manuel A. Caicedo, Miguel Cervera, Michele Chiumenti, Joan Baiges
Summary: This work introduces a distributed memory machine and octree-based Finite Element framework for modeling metal Additive Manufacturing processes. The framework accurately captures the complex geometry and physical phenomena using Adaptive Mesh Refinement, while keeping the number of FEs controlled.
COMPUTATIONAL MECHANICS
(2023)
Article
Materials Science, Composites
O. Haji, X. Song, A. Hivet, S. Rolland du Roscoat, L. Orgeas, A. Sinoimeri, G. Hivet, E. Blond
Summary: Understanding the mechanical behavior of quasi-parallel fiber networks is crucial for the development of fiber reinforced composite materials. This study presents a numerical model that accurately represents the fiber network geometry and simulates the main phenomena at the fiber scale. Experimental compaction of polyester fibers was performed and combined with X-ray tomography scans to create a CAD model for finite element simulations. The comparison between numerical and experimental results shows good coherence, demonstrating the potential of this approach.
APPLIED COMPOSITE MATERIALS
(2023)
Article
Environmental Sciences
Fei Wang, Zhendong Liu, Hongchun Zhu, Pengda Wu
Summary: This paper proposes a parallel method for filling open holes in large-scale 3D automatic modeling, which automatically identifies and classifies open holes, calculates hierarchical relationships between them, and fills them through topological closure and height projection. Experimental results show improved filling success rates and efficiency, with reduced time and memory consumption compared to traditional methods. The proposed method achieves natural transitions between partitioning cells and maintains filling accuracy similar to existing methods.
Article
Environmental Sciences
Xue Han, Jianfu Ni, Changchun Yin, Bo Zhang, Xin Huang, Jiao Zhu, Yunhe Liu, Xiuyan Ren, Yang Su
Summary: An adaptive octree meshing scheme is proposed for frequency-domain airborne electromagnetic modeling. The scheme improves efficiency and computational requirements by generating meshes more reasonably and refining them locally. The accuracy of the method is verified by comparing its results with semi-analytical solutions, and its technical advantages over the spectral-element method are demonstrated through computational cost comparisons. The feasibility of the algorithm in complex geological circumstances is also demonstrated.
Article
Engineering, Mechanical
Tianzeng Tao, Guozhong Zhao, Jingjuan Zhai, Shanhong Ren
Summary: This paper presents a novel adaptive piecewise model order reduction method for large-scale dynamical systems with viscoelastic damping. The method adaptively determines the orders using a curvature-based approach and gradually obtains convergent reduced-order models. Techniques such as influence coefficient method, order-dependent method, error estimation strategy, and comparison-selection method are proposed to accelerate convergence and determine the final reduced-order models.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2022)
Article
Energy & Fuels
Md Jamilur Rahman, Manzar Fawad, Nazmul Haque Mondol
Summary: This study investigates the hydromechanical effect on geomechanical failure in a potential CO2 storage site in Norway, considering stress and pore pressure changes induced by injection. The results show that pore volume and compressibility significantly influence the mechanical behavior of the reservoir and caprock rocks, and the lateral mechanical failure varies among different locations, suggesting the possibility of identifying safer injection points with less chances of leakage.
Article
Geochemistry & Geophysics
J. S. Kaeufl, A. Grayver, M. J. Comeau, A. Kuvshinov, M. Becken, J. Kamm, E. Batmagnai, S. Demberel
GEOPHYSICAL JOURNAL INTERNATIONAL
(2020)
Article
Astronomy & Astrophysics
Alexander Grayver, Alexey Kuvshinov, Dieter Werthmueller
Summary: This study presents a general framework for modeling three-dimensional EM induction effects in conducting planets, considering time-varying current systems and arbitrary distribution of electrical conductivity. The method is applicable to data measured at stationary observation sites and satellite platforms, enabling near real-time calculations of three-dimensional EM induction effects.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Adrian Tasistro-Hart, Alexander Grayver, Alexey Kuvshinov
Summary: Geomagnetic storms, controlled by the plasma magnetohydrodynamics of the solar-interplanetary-magnetosphere system, pose a significant challenge for physical forward modeling. Neural networks applied to storm forecasting require high-quality observational data and consideration of complex non-linear factors.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2021)
Article
Geosciences, Multidisciplinary
P. Alken, E. Thebault, C. D. Beggan, H. Amit, J. Aubert, J. Baerenzung, T. N. Bondar, W. J. Brown, S. Califf, A. Chambodut, A. Chulliat, G. A. Cox, C. C. Finlay, A. Fournier, N. Gillet, A. Grayver, M. D. Hammer, M. Holschneider, L. Huder, G. Hulot, T. Jager, C. Kloss, M. Korte, W. Kuang, A. Kuvshinov, B. Langlais, J. -M. Leger, V. Lesur, P. W. Livermore, F. J. Lowes, S. Macmillan, W. Magnes, M. Mandea, S. Marsal, J. Matzka, M. C. Metman, T. Minami, A. Morschhauser, J. E. Mound, M. Nair, S. Nakano, N. Olsen, F. J. Pavon-Carrasco, V. G. Petrov, G. Ropp, M. Rother, T. J. Sabaka, S. Sanchez, D. Saturnino, N. R. Schnepf, X. Shen, C. Stolle, A. Tangborn, L. Toffner-Clausen, H. Toh, J. M. Torta, J. Varner, F. Vervelidou, P. Vigneron, I. Wardinski, J. Wicht, A. Woods, Y. Yang, Z. Zeren, B. Zhou
Summary: The IAGA V-MOD working group adopted the thirteenth generation of the IGRF in December 2019, which includes definitive main field models for epoch 2015.0 and 2020.0, as well as predictive linear secular variations for 2020.0 to 2025.0. This update provides equations, spherical harmonic coefficients, and maps for magnetic parameters and their predicted changes from 2020.0 to 2025.0.
EARTH PLANETS AND SPACE
(2021)
Article
Geosciences, Multidisciplinary
Alexey Kuvshinov, Alexander Grayver, Lars Toffner-Clausen, Nils Olsen
Summary: This study presents results of mapping three-dimensional variations of the electrical conductivity in depths ranging from 400 to 1200 km using 6 years of magnetic data, and investigates the effect of different combinations of input data sets on transfer functions. A new global 1-D conductivity profile is also proposed based on a joint analysis of satellite tidal signals and global magnetospheric Q-responses.
EARTH PLANETS AND SPACE
(2021)
Article
Geochemistry & Geophysics
Friedemann Samrock, Alexander Grayver, Olivier Bachmann, Ozge Karakas, Martin O. Saar
Summary: Geophysical and petrological probes are crucial for understanding the structure and thermochemical state of active magmatic systems. While modern geophysical studies provide detailed 3-D subsurface images, there is still a need for methods to quantitatively link geophysical and petrological data for a more consistent description of magmatic processes.
EARTH AND PLANETARY SCIENCE LETTERS
(2021)
Correction
Geosciences, Multidisciplinary
Alexey Kuvshinov, Alexander Grayver, Lars Tofner-Clausen, Nils Olsen
EARTH PLANETS AND SPACE
(2021)
Article
Geochemistry & Geophysics
Alexander Grayver
Summary: This study presents global 3-D electrical conductivity models of the world ocean and marine sediments, and demonstrates a significant impact of these models on electromagnetic responses across a wide range of frequencies through numerical simulations. The inclusion of more realistic conductivity models of the ocean and seabed sediments is beneficial for both marine and land-based surveys designed for subsurface conductivity imaging or Space Weather modeling.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2021)
Article
Geochemistry & Geophysics
Matthew J. Comeau, Michael Becken, Alexander Grayver, Johannes S. Kaeufl, Alexey Kuvshinov
Summary: By analyzing high-resolution magnetotelluric data collected in central Mongolia, the structure of continental intraplate volcanic systems from surface to mantle source is revealed, showing low-resistivity anomalies in the middle-upper crust and lower crust, as well as thermal anomalies and partial melt zones in the mantle. The geophysical models provide insights into the continental intraplate volcanic system, indicating past transient magma pathways in the crust and a common mantle source for the volcanism.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Geochemistry & Geophysics
A. Mittelholz, A. Grayver, A. Khan, A. Kuvshinov
Summary: Using satellite magnetometer data, we derived the global electrical conductivity structure of the lunar upper and midmantle for the first time, showing striking similarity with the local analysis results from Apollo 12 and Explorer 35 magnetometer data.
JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS
(2021)
Article
Astronomy & Astrophysics
Alexander Grayver, Dan J. Bower, Joachim Saur, Caroline Dorn, Brett M. Morris
Summary: This article investigates the impact of stellar flares and associated CMEs on the interiors and atmospheres of planets. Using a physical model applied to the TRAPPIST-1 star, the study shows that magnetic flux carried by flare-associated CMEs results in planetary interior heating and leads to geological processes and volcanic activity. These findings are important for maintaining consistency in planetary atmospheric and geological models.
ASTROPHYSICAL JOURNAL LETTERS
(2022)
Article
Geochemistry & Geophysics
Federico D. Munch, Alexander Grayver
Summary: The USArray survey using magnetotelluric (MT) method provides a unique data set for imaging the electrical conductivity distribution in the United States. This study presents a new 3-D electrical conductivity model (MECMUS-2022) derived from 1291 USArray MT stations. The model incorporates a novel multi-scale imaging approach and accounts for the complex coastline and natural resolution footprint of MT transfer functions.
EARTH AND PLANETARY SCIENCE LETTERS
(2023)
Article
Geochemistry & Geophysics
Friedemann Samrock, Alexander Grayver, Marie Luise Texas Dambly, Madeleine R. Mueller, Martin O. Saar
Summary: Volcano-hosted high-temperature geothermal reservoirs are valuable resources for green electricity generation. Electromagnetic imaging methods can provide detailed characterization of geothermal systems, helping to understand the flow patterns of hydrothermal fluids and locate suitable drilling sites.
Article
Geosciences, Multidisciplinary
Jingtao Min, Alexander Grayver
Summary: In this study, we propose an approach that simultaneously reconstructs the inducing source and subsurface conductivity structures by exploiting the inherent physical link between them. We formulate the underlying inverse problem as a separable nonlinear least-squares problem and solve it using the variable projection method. We compare our approach with other conventional methods and demonstrate its feasibility by simultaneously reconstructing the ionospheric and magnetospheric currents along with a 1-D average mantle conductivity distribution from the ground magnetic observatory data.
EARTH PLANETS AND SPACE
(2023)
Article
Geochemistry & Geophysics
M. L. T. Dambly, F. Samrock, A. V. Grayver, M. O. Saar
Summary: The Main Ethiopian Rift is characterized by extensive volcanism and the formation of geothermal systems, directly impacting the lives of millions of people. Through the use of magnetotelluric method, a multi-scale 3D electrical conductivity model of a segment of the central Main Ethiopian Rift was obtained, revealing a magma ponding zone and its connection to Aluto volcano via a fault-aligned transcrustal magma system. This model provides important constraints for future geothermal developments and volcanic hazard assessments in the region.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)