Date: Thursday, February 15
Time: 3:40 pm - 5:00 pm
Location: 405 John D. Tickle Building
Over the past couple of decades, tremendous effort has been devoted to the development of multiscale computational modeling and simulation strategies for physics-based prediction of structural response. Among these strategies, concurrent multiscaling holds great potential in effectively bridging the “material” response to that of the “structure”. Yet these approaches are so computationally intensive that they remained within the academic realm, and have yet to make impact on realistic engineering problems.
We propose the Eigendeformation-based Reduced Order Homogenization Method (EHM) for computationally efficient and accurate concurrent multiscale analysis. We build and demonstrate this method to predict the response of structures made of polycrystalline materials, where crystal plasticity finite element (CPFE) simulations are concurrently coupled to a large scale structural analysis. EHM employs the idea of precomputing certain information on the material microstructure such as the influence functions, localization operators and coefficient tensors through RVE scale simulations, prior to the macroscale analysis. The reduced order modeling is achieved by being selective in what “physics” we choose to embed at the fine scales, as well as by developing sparse and scalable computational algorithms that can very efficiently solve the resulting multiscale systems.
We demonstrate the efficiency of the proposed approach in simulating the response of large structural problems (resolving each grain throughout the domain of the structure!) with modest computational resources. We also demonstrate the ability of the reduced order model to accurately capture the local, grain-scale features (grain level stress, strain, dislocation density evolution) and failure initiation mechanisms in the context of a high-performance titanium alloy (Ti-6242S).
Caglar Oskay is Associate Professor of Civil and Environmental Engineering, and the Mechanical Engineering Departments at Vanderbilt University. He received M.S. in Applied Mathematics, M.S. in Civil Engineering and Ph.D. in Civil Engineering at Rensselaer Polytechnic Institute. His research focuses on nonlinear response of heterogeneous materials and structures using computational modeling and simulation, including characterization of the failure response of systems that involve multiple temporal and spatial scales, and method development for failure analysis of composite systems subjected to impact, blast and other extreme loading and environmental conditions. Prof. Oskay is named Chancellor Faculty Fellow at Vanderbilt University in 2016 and Fellow of the American Society of Mechanical Engineers in 2017. Prof. Oskay also serves as the Associate Editor of the International Journal for Multiscale Computational Engineering.