Publications

Benchmark SEM3D sur des instances Google Cloud de type C2D optimisées pour le calcul utilisant le processeur AMD EPYC et sur GPU Nvidia A100

developer — Fri, 03 May 2024 09:03:36 +0000

Benchmark SEM3D sur des instances Google Cloud de type C2D optimisées pour le calcul utilisant le processeur AMD EPYC et sur GPU Nvidia A100 developer ven 03/05/2024 - 11:03

Cette contribution vise à montrer les résultats et performances du simulateur de propagation d’onde 3D à haute fidélité SEM3D (déposé [1, 2] et open source) sur GPU et sur cloud. SEM3D est principalement employé pour simuler des tremblements de terre dans le domaine solide-fluide, des failles actives à la surface libre, à travers des régions urbaines de ≈100 km × 100 km × 100 km de large. Les benchmarks effectués sur machine AMD sur Google Cloud Platform (GCP) et sur GPU Nvidia A100 sur le supercalculateur Jean Zay de l’IDRIS.

Distributed, Parallel, and Cluster Computing

Off CSMA 2024, 16ème Colloque National en Calcul des Structures 2024 Filippo Gatti, Ludovic Aubry, Éric Germaneau, Régis Cottereau, Wilfried Kirschenmann false lun 13/05/2024 - 11:19

Multiple-Input Fourier Neural Operator (MIFNO) for source-dependent 3D elastodynamics

developer — Thu, 02 May 2024 09:02:30 +0000

Multiple-Input Fourier Neural Operator (MIFNO) for source-dependent 3D elastodynamics developer jeu 02/05/2024 - 11:02

Numerical simulations are essential tools to evaluate the solution of the wave equation in complex settings, such as three-dimensional (3D) domains with heterogeneous properties. However, their application is limited by high computational costs and existing surrogate models lack the flexibility of numerical solvers. This work introduces the Multiple-Input Fourier Neural Operator (MIFNO) to deal with structured 3D fields representing material properties as well as vectors describing the source characteristics. The MIFNO is applied to the problem of elastic wave propagation in the Earth's crust. It is trained on the HEMEW^S-3D database containing 30000 earthquake simulations in different heterogeneous domains with random source positions and orientations. Outputs are time- and space-dependent surface wavefields. The MIFNO predictions are assessed as good to excellent based on Goodness-Of-Fit (GOF) criteria. Wave arrival times and wave fronts' propagation are very accurate since 80% of the predictions have an excellent phase GOF. The fluctuations amplitudes are good for 87% of the predictions. The envelope score is hindered by the small-scale fluctuations that are challenging to capture due to the complex physical phenomena associated with high-frequency features. Nevertheless, the MIFNO can generalize to sources located outside the training domain and it shows good generalization ability to a real complex overthrust geology. When focusing on a region of interest, transfer learning improves the accuracy with limited additional costs, since GOF scores improved by more than 1 GOF unit with only 500 additional specific samples. The MIFNO is the first surrogate model offering the flexibility of an earthquake simulator with varying sources and material properties. Its good accuracy and massive speed-up offer new perspectives to replace numerical simulations in many-query problems.

Artificial Intelligence

Off 2024 Fanny Lehmann, Filippo Gatti, Didier Clouteau false mer 01/05/2024 - 11:19

Efficiency comparison of MCMC and Transport Map Bayesian posterior estimation for structural health monitoring

developer — Wed, 01 May 2024 08:59:23 +0000

Efficiency comparison of MCMC and Transport Map Bayesian posterior estimation for structural health monitoring developer mer 01/05/2024 - 10:59

Engineering Sciences

Off Mechanical Systems and Signal Processing 2024 Jan Grashorn, Matteo Broggi, Ludovic Chamoin, Michael Beer false 10.1016/j.ymssp.2024.111440 lun 01/07/2024 - 00:00

NON-LOCAL CRACK INITIATION CRITERIA AND LIFETIME PREDICTION IN FRETTING-FATIGUE UNDER VARIABLE NORMAL LOADING CONDITIONS

developer — Fri, 26 Apr 2024 08:51:29 +0000

NON-LOCAL CRACK INITIATION CRITERIA AND LIFETIME PREDICTION IN FRETTING-FATIGUE UNDER VARIABLE NORMAL LOADING CONDITIONS developer ven 26/04/2024 - 10:51

Solid mechanics

Off European Conference on Fracture 2024 2024 Naansonou Patrick Lare, Florian Meray, Kévin Cosseron, Yoann Guilhem, Sylvie Pommier false lun 26/08/2024 - 11:19

Modèle non local pour la prise en compte des effets de gradient de contraintes en fretting-fatigue : Application aux contacts entre corps isotropes élastiquement dissimilaires

developer — Fri, 26 Apr 2024 08:51:29 +0000

Modèle non local pour la prise en compte des effets de gradient de contraintes en fretting-fatigue : Application aux contacts entre corps isotropes élastiquement dissimilaires developer ven 26/04/2024 - 10:51

Les problèmes de fretting ou de fretting-fatigue sont caractérisés par la présence d'un fort gradient de contraintes apparaissant en bords de contact. En se basant sur une analogie entre la mécanique de la rupture et la mécanique du contact, une description non locale simplifiée de la zone de contact est proposée et permet de prendre en compte de manière objective les effets de gradient. Cette description non locale consiste à partitionner le champ cinématique dans un référentiel attaché au front de contact en une somme réduite de termes, chaque terme de la décomposition étant le produit entre un facteur d'intensité et une fonction de forme identifiée a posteriori .

Solid mechanics

Off 16ième colloque national en calcul des structures 2024 Naansonou Patrick Lare, Y Guilhem, Florian Meray, S Pommier false lun 13/05/2024 - 11:19

Adaptive space-time model order reduction with dual-weighted residual (MORe DWR) error control for poroelasticity

developer — Sat, 20 Apr 2024 08:42:58 +0000

Adaptive space-time model order reduction with dual-weighted residual (MORe DWR) error control for poroelasticity developer sam 20/04/2024 - 10:42

Abstract In this work, the space-time MORe DWR ( M odel O rder Re duction with D ual- W eighted R esidual error estimates) framework is extended and further developed for single-phase flow problems in porous media. Specifically, our problem statement is the Biot system which consists of vector-valued displacements (geomechanics) coupled to a Darcy flow pressure equation. The MORe DWR method introduces a goal-oriented adaptive incremental proper orthogonal decomposition (POD) based-reduced-order model (ROM). The error in the reduced goal functional is estimated during the simulation, and the POD basis is enriched on-the-fly if the estimate exceeds a given threshold. This results in a reduction of the total number of full-order-model solves for the simulation of the porous medium, a robust estimation of the quantity of interest and well-suited reduced bases for the problem at hand. We apply a space-time Galerkin discretization with Taylor-Hood elements in space and a discontinuous Galerkin method with piecewise constant functions in time. The latter is well-known to be similar to the backward Euler scheme. We demonstrate the efficiency of our method on the well-known two-dimensional Mandel benchmark and a three-dimensional footing problem.

Engineering Sciences

Off Advanced Modeling and Simulation in Engineering Sciences 2024 Hendrik Fischer, Julian Roth, Ludovic Chamoin, Amélie Fau, Mary Wheeler, Thomas Wick false 10.1186/s40323-024-00262-6 jeu 18/04/2024 - 11:19

Non-intrusive model combination for learning dynamical systems

developer — Thu, 18 Apr 2024 08:37:02 +0000

Non-intrusive model combination for learning dynamical systems developer jeu 18/04/2024 - 10:37

Engineering Sciences

Off Physica D: Nonlinear Phenomena 2024 Shiqi Wu, Ludovic Chamoin, Qianxiao Li false 10.1016/j.physd.2024.134152 lun 01/04/2024 - 00:00

A simplified model for the wear prediction of plain bearings in the variable stator vane system

developer — Wed, 17 Apr 2024 08:37:01 +0000

A simplified model for the wear prediction of plain bearings in the variable stator vane system developer mer 17/04/2024 - 10:37

The wear of plain bearings in the variable stator vane (VSV) systems in a turbojet engine is a significant problem for compressor efficiency and stability requiring adapted models. The VSV bearings are located in a complex system and are exposed to combined and oscillating loads. This study aims to predict the wear evolution of the VSV bearings, considering the complexity of the system’s geometry and the loads with adapted computational time. This paper presents a three-dimensional formulation of this highly nonlinear wear problem under simplifying hypotheses in the objective to obtain a compromise between the quality of the prediction and the CPU time.

Materials and structures in mechanics

Off Tribology International 2024 Myriam Harnafi, Pierre-Alain Guidault, Pierre-Alain Boucard, Christian Paleczny false 10.1016/j.triboint.2024.109667 lun 01/04/2024 - 00:00

Utilisation de l'erreur en relation de comportement modifiée dans un dialogue essais-calculs - Application au contrôle d'essais sismiques

developer — Tue, 16 Apr 2024 08:36:37 +0000

Utilisation de l'erreur en relation de comportement modifiée dans un dialogue essais-calculs - Application au contrôle d'essais sismiques developer mar 16/04/2024 - 10:36

Le filtre de Kalman Dual Modifié (MDKF) est un nouveau cadre d'assimilation de données développé autour de l'Erreur en Relation de Comportement modifiée (ERCm), fonctionnelle d'identification au sens physique fort et robuste au bruit de mesure. L'objectif de cette contribution est d'utiliser le MDKF pour améliorer le contrôle d'essais sismiques sur structures endommageantes réalisés avec des tables vibrantes mues par actionneurs hydrauliques. Les résultats obtenus lors d'une première application basée sur un modèle simplifié sont prometteurs en vue de la mise en place de stratégies adaptatives.

Dynamique, vibrations

Off 16ème Colloque National en Calcul des Structures (CSMA 2024) 2024 M Diaz, P.-É Charbonnel, L Chamoin false lun 13/05/2024 - 11:19

DIC to evaluate a model composite system cracking due to CTE mismatch

developer — Thu, 11 Apr 2024 08:21:55 +0000

DIC to evaluate a model composite system cracking due to CTE mismatch developer jeu 11/04/2024 - 10:21

Coefficient of thermal expansion (CTE) mismatch in composites under temperature variation can lead to the system cracking. In this study, Digital Image Correlation (DIC) was used to investigate this phenomenon in a model composite system (MCS) composed of a single cylindrical inclusion into a ceramic mortar matrix. Temperature variation experiments assisted by DIC were conducted to evaluate the CTE mismatch of the MCS and to observe its cracking. An analytical model was used to fit the experimental radial displacement field of the MCS, which allowed the computation of the inelastic maximum principal strain field, highlighting the radial crack pattern. The crack initiation and propagation were evaluated via damaged elements in the interface region and the computation of the average Mean Crack Opening Displacement and Surface Crack Density for crack regions. This methodology is appliable for a single inclusion MCS, with improvement perspectives for application in multiple inclusions MCS.

Materials

Off Theoretical and Applied Fracture Mechanics 2024 Igor Paganotto Zago, Rafael Vargas, Vinicius Fiocco Sciuti, Rodrigo Bresciani Canto, Ricardo Afonso Angélico false 10.1016/j.tafmec.2024.104330 sam 01/06/2024 - 00:00