刘兆暐报告通知(2018--55)


发布时间: 2018-08-27     浏览次数: 109

报告题目:An Isogeometric Coupled Boundary Element Method and Finite Element Method for Structural-Acoustic Analysis through Loop Subdivision Surfaces

报 告 人Zhaowei Liu

地    点河海大学江宁校区乐学楼1030

时    间:2018.08.28 上午 1000-1200

报告人简介:Dr. Liu is a PhD student of computational mechanics in School of Engineering, University of Glasgow. He has finished thestudy and submitted the PhD thesis on 10th August 2018. During his PhD studies, Dr. Liu has also worked as a short termresearch assistant at both the University of Nottingham and University of Glasgow. He is going to undertake a researchassociate role in the School of Engineering at the University of Glasgow starting from October 2018. His PhD wasfollowed his MSc from Cardiff University and BEng from University of Liverpool. His research focused on integratingComputer Aided Design (CAD) with novel numerical methods. He has cutting-edge knowledge specifically in the topic ofisogeometric boundary element methods and its application to solid mechanics, acoustics, electromagnetics, computeraided design and shape optimization. He has published three peer-reviewed journal papers during his PhD studiesincluding one paper as first author, published in a highly-rated journal: International Journal of Numerical Method inEngineering. The remaining papers he is second author published in the Journal of Computational Physics andEngineering Analysis with Boundary Elements.

报告摘要:This present work proposes a novel approach for coupling finite element and boundary element formulations using a Loop subdivision surface discretisation to allow efficient acoustic scattering analysis over shell structures. The analysis of underwater structures has always been a challenge for engineers because it couples shell structural dynamics and acoustic scattering. In the present work, a finite element implementation of the Kirchhoff-Love formulation is used for shell structural dynamic analysis and the boundary element method is adopted to solve the Helmholtz equation for acoustic scattering analysis. The boundary element formulation is chosen as it can handle infinite domains without volumetric meshes. In the conventional engineering workflow, generating meshes of complex geometries to represent the underwater structures, e.g. submarines or torpedoes, is very time consuming and costly even if it is only a data conversion process. Isogeometric analysis (IGA) is a recently developed concept which aims to integrate computer aided design (CAD) and numerical analysis
by using the same geometry model. Non-uniform rational B-splines (NURBS), the most commonly used CAD technique, were considered in early IGA developments. However, NURBS have limitations when used in analysis because of their tensor-product nature. Subdivision surfaces discretisation is an alternative to overcome NURBS limitation. The new method adopts a triangular Loop subdivision surface discretisation for both geometry and analysis. The high order subdivision basis functions have C1 continuity, which satisfies the requirements of the Kirchhoff-Love formulation and are highly efficient for the acoustic field computations. The control meshes for the shell analysis and the acoustic analysis have the same resolution, which provides a fully integrated isogeometric approach for coupled structural-acoustic analysis of shells. The method is verified by the example of an acoustic plane wave which scatters over an elastic spherical shell. The ability of the presented method to handle complex geometries is also demonstrated.