Seminar: Stabilized and Accelerated Meshfree Method for Extreme Events Modeling

Where: 
Mason Building, Room 1133
When: 
Monday, February 19, 2018 - 13:45

 

Dr. Jiun-Shyan Chen
William Prager Chair Professor, Structural Engineering Department
Director, Center for Extreme Events Research
University of California, San Diego
 
Abstract:

Meshfree methods such as the Reproducing Kernel Particle Method (RKPM) are well suited for modeling materials and solids undergoing fracture and damage processes, and nodal integration is a natural choice for this class of problems. However, nodal integration suffers from spatial instability, and the excessive material deformation and damage process could also lead to kernel instability in RKPM. This presentation introduces the recent advances in meshfree methods that are stable, efficient, and with optimal convergence. A variationally consistent integration (VCI) is introduced to allow correction of many low order quadrature rules to achieve optimal convergence, and stabilization techniques with implicit gradient are developed for nodal integration. Independent to the quadrature rules, a quasi-linear Reproducing Kernel approximation is constructed to address the kernel instability issue. Several RKPM shock algorithms are also formulated under the variationally consistent nodal integration framework. The application of the new RKPM formulation for fracture to damage multiscale modeling, and their applications to the modeling of extreme events, are demonstrated. The demonstration problems include the modeling of man-made disasters such as fragment-impact processes, penetration, shock and blast events, as well as simulation of natural disasters such as landslide.

Biography:

J. S. Chen received Ph.D. from Theoretical & Applied Mechanics, Northwestern University in 1989. He is currently the Inaugural William Prager Chair Professor of Structural Engineering Department and the Director of Center for Extreme Events Research at UC San Diego. Before joining UCSD in October 2013, he was the Chancellor’s Professor of UCLA Civil & Environmental Engineering Department where he served as the Department Chair during 2007-2012. J. S. Chen’s research is in computational mechanics and multiscale materials modeling with specialization in the development of meshfree methods. He is the Past President of US Association for Computational Mechanics (USACM) and the Past President of ASCE Engineering Mechanics Institute (EMI). He has received numerous awards, including the Computational Mechanics Award from International Association for Computational Mechanics (IACM), Ted Belytschko Applied Mechanics Award from ASME Applied Mechanics Division, The Belytschko Medal from USACM, the ICACM Award from International Chinese Association for Computational Mechanics (ICACM), among others. He is the Fellow of USACM, IACM, ASME, EMI, ICACM, and ICCEES.