An Efficient Augmented Finite Element Method for Arbitrary Cracking and Crack Interaction in Solids

来源:力学与工程学院  返回:ca88     日期:2019/6/3 9:58:10   点击数:759  

时间:2019-06-05 15:00


报告人:Qingda Yang



Dr. Qingda Yang is a full professor of the Department of Mechanical and Aerospace Engineering at the University of Miami (Coral Gables, FL). He obtained his B.S. (Engineering Mechanics, 1991) and M. S. (solid mechanics, 1994) from Zhejiang University, China, and a PhD (Mechanical Engineering, 2000) from University of Michigan at Ann Arbor. Prior to joining University of Miami, Dr. Yang worked for Rockwell Scientific Company (formerly known as Rockwell Science Center) as a solid mechanics scientist from 2000 to 2006.

Dr. Yang joined the faculty of the Department of Mechanical and Aerospace Engineering at the University of Miami in 2006. Dr. Yang’s recent research has focused mainly on developing multi-scale methodologies that can lead to realistic virtual testing and designing of complex heterogeneous materials and structures under general and/or extreme thermal-mechanical loading environments. His research has attracted funding from many federal agencies and industrial companies. Dr. Yang is an author/coauthor of more than 90 peer-reviewed journal publications, 4 book chapters, and 30 refereed conference proceedings. He is an editorial board member for the Journal of Applied Composite Materials and the journal of Multifunctional Composites.


New heterogeneous materials such as polymer matrix composites (PMCs), metal-matrix composites (MMCs), and ceramic matrix composites (CMCs) are playing rapidly increasing roles in current and future applications.  Despite considerable research efforts in the past decade the strength and durability prediction remains a challenging research topic. Advanced numerical methods that can explicitly resolve the multiple damage processes and their nonlinear coupling at various scales are highly desired.

In this talk I shall present a recently developed augmented finite element method (A-FEM). The A-FEM formulation employs internal nodes to account for the crack displacements due to an intra-elemental weak or strong discontinuity and it permits repeated elemental augmentation to include multiple interactive cracks within a single element. It thus enables a unified treatment of damage evolution from a weak discontinuity to a strong discontinuity, and to multiple interactive cohesive cracks, all within a single element that employs standard external nodal DoFs only. I shall also present a novel elemental condensation procedure that can efficiently solve the internal nodal DoFs as explicit functions of the nodal DoFs for any irreversible, piece-wise linear cohesive laws, which leads to a fully-condensed elemental equilibrium equation with mathematically exactness. The new A-FEM’s high-fidelity simulation capabilities to interactive cohesive crack formation and propagation in homogeneous and heterogeneous solids will be demonstrated through several numerical examples. Finally, detailed implementation of such elements into commercial software package ABAQUS will be discussed.



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