纪念华东水利学院建院70周年学术活动:Prof. Andrew Chan(陳衍昌)系列学术报告通知(聘请外国文教专家项目)(2022-41)


发布时间: 2022-09-16     浏览次数: 12

报告主题: Computational Geomechanics modelling of saturated soil and rocks

报 告 人:Prof. Andrew Chan (陳衍昌), University of Tasmania

报告时间:

      2022年09月19日下午14:00-17:00

      2022年09月20日下午14:00-17:00

      2022年09月21日下午14:00-17:00

      2022年09月22日下午14:00-17:00

报告地点:乐学楼832或腾讯会议:869-8792-7023

主办单位:力学与材料学院工程力学研究所

欢迎广大师生参加!


Outline of lectures:

Day 1:Numerical modelling of dynamic saturated soil and pore fluid interaction using finite element method – Theory and validation.

Earthquake induced liquefaction has caused extensively damage to various cities and one of the most notable one is the damage caused to Christchurch during the Lyttelton earthquake on 22nd February 2011. Liquefaction occurs because of the interaction between the soil particles and its pore fluid. The seminar will describe the cause of liquefaction and the typical damage it causes. Then the mathematical model, Biot formulation, governing the saturated soil and pore fluid interaction will be given together with the stress-strain relationship used in modelling the material behaviour.


Day 2: Numerical modelling of dynamic saturated soil and pore fluid interaction using finite element method – Comparisons with centrifuge modelling and real-life example.

Computational results and their comparison with centrifuge experiments especially the results from VELACS project will then be presented to validate the approach. A real life example of the seismic evaluation of an earth dam in Italy will also be presented.


Day 3: Numerical modelling of dynamic saturated soil and pore fluid interaction using combined discrete element and Lattice Boltzmann method

Strictly speaking, soil cannot be described as a continuum especially when liquefaction or fluidisation phenomenon occurs and discrete element method provides a better description of the interaction between the soil particles. On the other hand, the Lattice Boltzmann method provides a simple but microscopic description of the fluid thus allowing a detailed modelling of the interaction between the particles and the pore fluid. Results obtained using this combined DEM-LBM strategy for soil erosion due to pipe leakage will be presented and its strengths and weaknesses in comparison with the finite element method will be discussed.


Day 4: Numerical analysis of fracture and breakage of brittle material using combined continua and discontinua method

In this seminar, the physical behavior of brittle material such as glass and rock before and after fracture is examined. They are governed, in part, by two mechanisms viz. surface-to-surface interaction; and the fracture breakage of the individual surfaces. Surface interaction is predominantly described by the contact condition of the surfaces, whereas particle breakage depends on the stress state within each grain. Both the grain interaction and its corresponding stress state have to be appropriately accounted for when modelling the behavior of granular media. To achieve these objectives, this study examines two combined continua and discontinua methods:

1.          1.     Combined Finite discrete element method pioneered by Ante Munjiza

2.     A novel computational framework that combines the use of the scaled boundary finite element method (SBFEM) and the discrete element method (DEM).

Both approaches employ the DEM to resolve the contact condition and the dynamics of the particle interaction and use the FEM and SBFEM respectively to determine the stress state in individual grains. The stress state in a particle determines the condition for particle breakage according to a prescribed failure criterion. Both methods therefore, exploit the best features of both the discontinua DEM and continua method FEM/SBFEM. Each particle within the framework of the DEM and the FEM/SBFEM. The use of arbitrary sided polygonal particles in SBFEM enable the morphology of each grain to be modelled using a single polygon thus making this method more efficient than the use of FEM in the stress analysis in individual particle. The flexibility of both approaches therefore, adapts very well to the evolving geometries of the granular medium during the loading process. The effectiveness of the developed method is demonstrated through parametric studies to highlight the role of the particle breakage on the behavior of granular media at both the macroscopic and particle scales.


报告人简介:

Prof. Chan joined the University of Tasmania, Australia, in March 2015 and he is currently Professor of Engineering. He received his BSc(Eng) and MPhil from university of Hong Kong then he completed his PhD study at the University of Wales, Swansea. He has spent time working as a Postdoctoral Research Assistant at Cambridge University, and has lectured in the Department of Civil Engineering at the University of Glasgow. Prof. Chan was then appointed Reader and Professor in Computational Engineering at University of Birmingham. When moved to Australia, he took up a professorial and deputy dean position at University of Ballarat (later renamed Federation University Australia) before moving to Tasmania to take up the Headship of School of Engineering. 

He has a wide research interest. He is one of the world leading experts in the use of the finite element method of static and dynamic fully coupled soil and pore-fluid interaction and the author of two comprehensive Finite Element packages for deformable porous media and pore fluid interaction. His recent interest, besides the use of Scaled Boundary Finite Element Method and Discrete Element Method for the modelling of particle breakage, includes simulating the breakage of glass under hard body impact using the combined finite-discrete element method and Modelling dynamic saturated soil and pore fluid interaction such as fluidization using combined discrete element method and Lattice Boltzmann method. He is subject editor for the Journal of Applied Mathematical Modelling and on the editorial board of Computers and Structures. The second edition of his co-authored book Computational Geomechanics: Theory and Applications, 2nd Edition, has just been published by Wiley.