Events

I³MS - Nóbrega Seminar

Location: AICES Seminar Room 115, 1st floor, Schinkelstr. 2, 52062 Aachen

Prof. Dr. Juan Miguel Nóbrega - Computational Rheology and Polymer Processing at the University of Minho

Department of Polymer Engineering, University of Minho, Portugal

Abstract

 

Nowadays, aiming an efficient use of resources, the advantages of employing numerical modelling tools to assist any design activity are consensual. Therefore, there are countless modelling software packages available, both commercial and open-source, which can be used to study extremely complex systems.

In the past, the open-source numerical codes presented very specific/limited capabilities and were developed by small research teams. Nowadays, some communities that develop and work with open-source codes are substantially enlarged and better organised. Hence, given the large range of skills covered by the development teams, some of these open-source codes cover a very wide range of applications. One successful case of this type is the OpenFOAM® computational library, which can model complex multiphysics systems, covering both fluid and solid behaviours, being fully parallelized. One of the main advantages of OpenFOAM® is its adaptiveness, resorting to a symbolic programming language, that allows a straightforward development of new applications for the resolution of specific problems, not available on the distributed releases.

This talk will begin with a brief presentation of the OpenFOAM® computational library, its main features and capabilities. Then, several ongoing/recent case studies in the frame of computational rheology, polymer processing and related applications will illustrate its potential.

4th International Conference on Computational Engineering (ICCE 2017)

Location: Darmstadtium Conference center next to Technische Universität Darmstadt

The International Conference on Computational Engineering (ICCE), which takes place from Thursday, September 28, to Friday, September 29, 2017, provides a meeting place for researchers and practitioners working on computational methods in all disciplines of engineering and applied mathematics, with a special focus on doctoral researchers and young scientists. The aim of the conference is to discuss the state of the art in this challenging field, develop promising perspectives for future research and initiate cooperations.

The conference is organized by the Graduate School of Computational Engineering (GSC CE) at TU Darmstadt together with the International Graduate School of Science and Engineering (IGSSE) at Technical University of Munich, the Stuttgart Research Center for Simulation Technology (SimTech) at University of Stuttgart and the Aachen Institute for Advanced Study in Computational Engineering Science (AICES) at RWTH Aachen University.

EU Regional School - Auricchio Seminar

Location: AICES Seminar Room 115, 1st floor, Schinkelstr. 2, 52062 Aachen

Prof. Dr. Ferdinando Auricchio - ADDITIVE MANUFACTURING PROCESSES: From Materials to Applications, From Micro- to Macro-Simulations

Department of Civil Engineering and Architecture
University of Pavia, Italy

Abstract

Additive Manufacturing (AM) is taking off in many industrial processes, since it allows geometries and flexibility unthinkable not too long ago. However, AM is a very complex process, involving complex phenomena (e.g., heat conduction, phase change, surface change and residual stress rising), requiring dedicated design and simulation tools.

The presentation will give an overview of different materials currently adopted in AM, of possible applications where AM is successfully exploited (both in industrial and research environments), addressing also  design and simulation aspects, both at the microscopic scale (involving powder melting/solidification, melt pool fluid motion, geometry surface change) and at the macroscopic scale, performed using a commercial code.

Lecture Material

EU Regional School -Raul F. Tempone Seminar

Location: AICES Seminar Room 115, 1st floor, Schinkelstr. 2, 52062 Aachen

Prof. Dr. Raul F. Tempone - On Monte Carlo and Multilevel Monte Carlo

Computer, Electrical and Mathematical Science and Engineering Division
King Abdullah University of Science and Technology, Kingdom of Saudi Arabia

Abstract

We describe and analyze the Monte Carlo (MC, Multi-Index Monte Carlo (MIMC) and the Multi-Index Stochastic Collocation  (MISC) method for computing statistics of the solution of a PDE with random data. MIMC is both a stochastic version of the combination technique introduced by Zenger, Griebel and collaborators and an extension of the Multilevel Monte Carlo (MLMC) method first described by Heinrich and Giles. Instead of using first-order differences as in MLMC, MIMC uses mixed differences to reduce the variance of the hierarchical differences dramatically. These mixed differences yield new and improved complexity results, which are natural generalizations of Giles's MLMC analysis, and which increase the domain of problem parameters for which we achieve the optimal convergence. On the same vein, MISC is a deterministic combination technique based on mixed differences of spatial approximations and quadratures over the space of random data. Provided enough mixed regularity, MISC can achieve better complexity than MIMC. Moreover, we show that, in the optimal case, the convergence rate of MISC is only dictated by the convergence of the deterministic solver applied to a one-dimensional spatial problem. We propose optimization procedures to select the most effective mixed differences to include in MIMC and MISC. Such optimization is a crucial step that allows us to make MIMC and MISC computationally efficient. We show the effectiveness of MIMC and MISC in some computational tests using the mimclib open source library, including PDEs with random coefficients and Stochastic Interacting Particle Systems.  
 
References: 
1-   ”Multi-Index Stochastic Collocation for random PDEs”, by A. L. Haji Ali, F. Nobile, L. Tamellini and R. Tempone. Computers and Mathematics with  Applications, Vol. 306,  pp. 95--122, 2016.
 
2-   “Multi-index Stochastic Collocation convergence rates for random PDEs with parametric regularity, by A. Haji-Ali, F. Nobile, L. Tamellini, R. Tempone. Foundations of Computational Mathematics”, Vol. 16(6), Pages 1555-1605, 2016.
 
3-    “Multi Index Monte Carlo: When Sparsity Meets Sampling”, by A.-L. Haji-Ali, F. Nobile, and R. Tempone. Numerische Mathematik, Vol. 132(4), Pages 767–806, 2016. 
 
4- "Multilevel and Multi-index Monte Carlo methods for McKean-Vlasov equations”, by  A. L. Haji Ali and R. Tempone. ArXiv:1610.09934, October 2016.  To appear in Statistics and Computing, 2017.
 
5- "Sparse approximation of multilinear problems with applications to kernel-based methods in UQ", by F. Nobile, R. Tempone, and S. Wolfers. ArXiv:1609.00246, August 2016.  

Aachen Conference on Computaional Engineering Science 2017

Location: RWTH Super-C Building, Templergraben 57, 52056 Aachen, Germany

in Honor of Wolfgang Dahmen

The Aachen Conference on Computational Engineering Science (AC.CES) brings together leading experts in theory, method development, and applications related to problems in computational engineering. The main objectives of the conference are to present cutting-edge research and to facilitate interdisciplinary collaboration. The conference consists of a series of plenary sessions featuring invited talks by leading experts. The plenary lectures will be complemented by a poster session.

In 2017 the conference will be held in honor of Wolfgang Dahmen to celebrate his numerous contributions in Applied Mathematics.
 

Conference Topics:

  • Approximation Theory
  • High Dimensional Problems
  • Imaging / Electron Microscopy
  • Numerical Methods for PDEs

More information and tickets can be found here.