Ean Tat Ooi博士系列学术讲座报告(2020-35、36)

发布时间: 2020-12-11     浏览次数: 92

报告人:Ean Tat Ooi博士
School of Science, Engineering & Information of Technology
Federation University of Australia
主办单位:  国际合作处力学与材料学院动力学与控制研究所

报告题目1:Development of a class of scaled boundary finite element-based shape functions and their applications in engineering
时间:2:00 pm-3:00 pm, 2020年12月12日

报告简介:The scaled boundary finite element method is a semi-analytical numerical technique that was developed by Song and Wolf [1] in the late 1990’s. The analytical representation of the variables of interest within the discretized domain enabled efficient solutions to niche applications such as in unbounded domains and fracture. In its original formulation, the stiffness matrix of computational domain was obtained directly from the solution of the partial differential equation governing the problem. This approach makes it difficult to extend the application of the scaled boundary finite element method to more complex engineering problems such as those involving material nonlinearity, heterogeneous materials and coupled field problems. In this study, an alternative approach to formulate the scaled boundary finite element method is presented through the development of a class of scaled boundary shape functions. This technique results in a general formulation of the scaled boundary finite element method that is very similar to the finite element method. As a result, standard finite element techniques that are used in engineering analyses including those involving material nonlinearities, stochastic analyses and coupled field analysis can be applied and thus enabling such types of problems to be analyzed using the scaled boundary finite element method. Resulting from this, a separate class of high order scaled boundary finite shape functions can also be derived that exhibits efficient analysis for problems of the Poisson type and thermoelastic fracture. Combined with the advantages of the scaled boundary finite element method in pre-processing through the use of polygonal meshes, quadtree meshes and image-based analysis, the application of this general formulation is presented for the engineering problems abovementioned e.g. elastoplasticity, slope stability, poroelasticity, stochastic analysis and transient coupled thermo-elasticity.

报告题目2:A dual scaled boundary finite element formulation over arbitrary faceted polyhedra
时间:2:00 pm-3:00 pm, 2020年12月13日

报告简介:A novel technique based on the scaled boundary finite element method applicable to arbritrary faceted polyhedra in three-dimensions is presented. The formulation requires that a scaling requirement dictated by star-convexity is satisfied and the polyhedron facets are planar. This geometric requirement can be conveniently satisfied by many polyhedra. For those that do not meet this requirement, a subdivision followed by a triangulation process can be applied to non-planar facets to generate an admissible geometry. The formulation adopts two separate scaled boundary coordinate systems; one with respect to: (i) a scaling centre located within a polyhedron and; (ii) a set of scaling centres located on a polyhedron’s facets. The polyhedron geometry is scaled with respect to both the scaling centres. Polygonal shape functions are derived using the scaled boundary finite element method on each of the polyhedron facets. The stiffness matrix of a polyhedron is then obtained semi-analytically similar to the standard procedures of the scaled boundary finite element method in three dimensions. In the proposed technique, numerical integration is required only for the line elements that discretize the polyhedron boundaries. The new formulation passes the patch test. Application of the new formulation in computational solid mechanics is demonstrated using a few numerical benchmarks.

Dr.EanTatOoi is an associate professor in structural engineering within the Faculty of Science in Federation University Australia. He obtained his PhD from Nanyang Technological University Singapore. He is an active researcher in the field of computational mechanics and has held research positions in the National University of Singapore, the University of Liverpool and the University of New South Wales. His research focus is on the development of the Scaled Boundary Finite Element Method (SBFEM); a semi-analytical numerical technique for computational modelling. He is one of the pioneers in establishing a framework for polygonal based SBFEM for fracture mechanics simulations. He has published over 40 papers in the high quality journals.