Seminar on Micromorphic Theory For Architected Structures And Nonlocal Model For Fracture In Solids

18 Nov 2024 10.00 AM - 11.00 AM The Arc, Level 1, LHN TR+18 Current Students, Public

Prof J.N Reddy

Director, Center of Innovation in Mechanics for Design and Manufacturing

Texas A&M University, USA

This seminar will be chaired by Prof Zhou Kun.

Seminar Abstract

The lecture will present the speaker’s recent research in: (1) a micromorphic approach for modeling architected materials and structures [1] and (2) a nonlocal approach to model onset and propagation of fracture in solids [2,3]. In the first case, the non-local continuum models that account for material and/or structural length scales are discussed to model architected materials and structures (e.g., web-core sandwich panels) using the micropolar elasticity. In the second topic, a thermodynamically consistent fracture model for brittle and quasi-brittle solids based on Graph-based Finite Element Analysis (GraFEA) is discussed. These studies formulated a graph-based approach in two-dimensional and three-dimensional models, implementing it in Abaqus/Explicit using a vectorized user material subroutine (VUMAT). The computational technique also incorporates a probabilistic approach to damage growth by using a measure of “microcrack survival probability” and its evolution. The approach will be demonstrated using several examples.

References

1.  Praneeth Nampally, Anssi Karttunen, and J.N. Reddy, European Journal of Mechanics, A/Solids, 74, 431-439, 2019.

2. Thamburaja, P., et al. "Fracture modelling of plain concrete using non-local fracture mechanics and a graph-based computational framework." Proceedings of the Royal Society A 477.2252 (2021): 20210398.

3. Srinivasa, A. R., et al. "Multiple cracking model in a 3D GraFEA framework." Continuum Mechanics and Thermodynamics 33 (2021): 1409-1428.

    Speaker's Biography 
    Dr. Reddy is a Distinguished Professor, Regents’ Professor, and inaugural holder of the Oscar S. Wyatt Endowed Chair in Mechanical Engineering at Texas A&M University, College Station, Texas. Dr. Reddy, an ISI highly-cited researcher, is known for his significant contributions to the field of applied mechanics through the authorship of 25 textbooks and over 800 journal papers. His pioneering works on the development of shear deformation theories (that bear his name in the literature as the Reddy third-order plate theory and the Reddy layerwise theory) have had a major impact and have led to new research developments and applications. Some of the ideas on shear deformation theories and penalty finite element models of fluid flows have been implemented into commercial finite element computer programs like ABAQUS, NISA, and HyperXtrude. In recent years, Reddy's research has focused on the development of locking-free shell finite elements and nonlocal and non-classical continuum mechanics problems involving couple stresses and damage and fracture in solids. 
    Dr. Reddy has received numerous honors and awards. Most significant ones include: 2022 IACM Congress (Gauss-Newton) Medal, 2019 SP Timoshenko Medal from American Society of Mechanical Engineers, 2018 Theodore von Karman Medal from the American Society of Civil Engineers, the 2017 John von Neumann Medal from the U.S. Association of Computational Mechanics, the 2016 Prager Medal from the Society of Engineering Science, and 2016 ASME Medal from American Society of Mechanical Engineers.  He is a member the US National Academy of Engineering and foreign fellow of the Chinese Academy of Engineering (in addition to six other foreign academies).

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