Faculty of Engineering and Natural Sciences
FENS ME 551 SEMINARS
Multiscale Modeling of Failure in Materials and Structures
Asst.Prof.Dr. Çağlar Oskay
Civil and Environmental Engineering, Vanderbilt University
Computational prediction of failure in complex, heterogeneous materials are critical to design of novel mechanical and functional components and structures subjected to extreme environments and loading conditions. The available single-scale modeling and simulation technology does not have the capability to solve such complex problems. This is mainly because it fails to account for the strong coupling effects between physical processes occurring in multiple spatial and temporal length scales triggered by extreme environments and loads.
We present a new computational multi-scale framework for failure analysis of complex materials and structures subjected to extreme events. We will examine three classes of space-time multiscale problems. (1) The temporal multiscale aspects are presented by considering a fatigue life prediction problem. Fatigue is a multiscale phenomenon in time because of the disparity between the loading period and the overall life of a structural component. The original boundary value problem defining the fatigue process is decomposed into coupled micro-chronological and macro-chronological problems within the framework of mathematical homogenization. (2) In the second part of the talk, we generalize the classical mathematical homogenization theory to account for failure of heterogeneous materials. An adaptive mesoscale model is developed based on the eigendeformation-based model reduction methodology to efficiently and accurate evaluate the nonlinear failure response. (3) In the last part of the talk, failure modeling of heterogeneous thin structures will be presented in the context of plate theory. The analysis of thin structures brings an additional layer of complexity due to the presence of an additional length scale: the thickness of the structure.
Bio-sketch: Dr. Çağlar Oskay is an Assistant Professor in the Civil and Environmental Engineering Department at Vanderbilt University. Prior to his current appointment, he worked at the Scientific Computation Research Center and Civil Engineering Department at Rensselaer Polytechnic Institute as a Postdoctoral Research Associate. He received an M.S. degree in Applied Mathematics, M.S. in Civil Engineering and a Ph.D. degree in Civil Engineering at RPI. He completed his undergraduate studies in the Middle East Technical University. His area of expertise is in the field of multiscale computational mechanics, solid and structural mechanics. His research focuses on multiscale modeling of advanced materials when subjected to extreme events, as well as modeling and simulation of complex multiscale-multiphysics systems.
December 24, 2008, 13:40, FENS L065