A Co-rotational Kinematic Framework for Large Deformation Analysis

Speaker: Dr. Arif Masud, Department of Civil and Environmental Engineering, The University of Illinois at Urbana-ChampaignThis talk presents a hierarchical approach to the modeling of multi-layered composites with arbitrary ply lay-up sequences and orientations. The approach is applicable to flat as well as curved geometric configurations. The model is based on a co-rotational procedure that is derived consistently from the updated Lagrangian framework. The underlying variational formulation is based on an assumed strain method. Displacements and rotations are assumed finite while the strains are infinitesimal. The close relationship between the co-rotational procedure and its underlying updated Lagrangian framework is presented to highlight the cost reduction for large and complicated geometric configurations. Some simple but mathematically consistent procedures for updating element stresses and calculating the internal force vector are also discussed.
An elastoplastic damage model is incorporated in this co-rotational framework to accommodate material degradation in each individual laminate. The model is based on irreversible thermodynamics with the damage surface defined in terms of an internal damage variable of energy, along with a set of rate-independent elastoplastic constitutive equations that are defined in an effective stressâ€"strain space. Employing the operator splitting methodology, a three-step predictor/multi-corrector algorithm is developed that includes an elastic predictor, a plastic corrector, and a damage corrector.
Several representative numerical simulations of materially and geometrically nonlinear analysis are presented to show the accuracy and the range of applicability of the model. The model is then applied to the design of a co-axial laminated system.Vita: Professor Arif Masud received Ph.D. in Computational Mechanics from Stanford University in April 1993. He joined the University of Illinois at Urbana-Champaign in August 2006, after having served on the faculty of University of Illinois at Chicago from 1994-2006. Dr. Masud is working on the development of multi-scale finite element methods for application in nonlinear solid and fluid mechanics. He has delivered several Keynote Lectures at International Conferences, and organized more than ten International Symposia on Multiscale & Stabilized Finite Element Methods. He is co-editor of the book The Finite Element Method: 1970s and Beyond that appeared in 2004. In 1999 he was awarded the Teaching Recognition Award by the Council for Excellence in Teaching at UIC, and in 2002 he was awarded the Faculty Distinguished Research Award by the College of Engineering at UIC. Dr. Masud serves on the Editorial Boards of five International Journals. He is Chair of the Computational Mechanics Committee of ASCE, and Vice-Chair of the Fluid Mechanics Committee of ASME. Dr. Masud serves as an Associate Editor of the ASCE Journal of Engineering Mechanics, and an Associate Editor of the ASME Journal of Applied Mechanics. In 2006 he was elected Fellow of the International Association of Computational Mechanics (IACM).

Location: Kaprielian Hall (KAP) - 209

Audiences: Everyone Is Invited

Contact: Evangeline Reyes