报告题目：Micro to macro scale modelling of anisotropic heterogeneous materials

报告时间：2022年6月8日（周三） 上午10:00-12:00

报告地点：建筑工程学院8#202

报告人：李培

报告人单位：西安交通大学机械工程学院国际机械中心

报告人简介：Prof. Pei Li is an associate professor in the International Machinery Center, School of Mechanical Engineering at Xi’an Jiaotong University. Before joining Xi’an Jiaotong University, he has worked as an assistant professor in the Department of Mechanical Engineering at University of Twente, supported by the Dutch National Talents Plan “Sectorplan Techniek”. Prior to that, Prof. Pei Li finished his PhD and postdoctoral research at National University of Singapore, under the supervision of Prof. Victor P. W. Shim and Prof. Vincent B. C. Tan respectively. Prof. Pei Li’s research interest is including but not limited to impact mechanics, lightweight cellular materials, 3D printed structures and materials, multiscale analysis of heterogeneous materials and so on.

报告摘要：Many materials such as cellular materials, composites and alloys are heterogeneous, and their microstructure essentially determines their macro-scale mechanical behaviour. A good understanding of the macro-scale behaviour and the underlying micro-scale mechanism of such materials will be valuable to guide their applications, and to optimize and design new materials with excellent mechanical performance. To this end, an anisotropic polymeric foam was studied as an example, in terms of experiments, micro/meso-scale finite element (FE) simulation and constitutive modelling. The polymer foam was first subjected to static and dynamic compression at various angles to foam-rise direction, to characterise the anisotropy and strain rate-dependence of its mechanical response. To analyse the mechanisms for various macro-crushing modes and associated post-yield hardening responses observed in compression tests along different directions, a micro/meso-scale structural FE model, comprising an assembly of foam cells, was established and employed to examine meso-scale deformation of foam cells. Finally, a continuum constitutive model with anisotropic post-yield hardening was developed, for incorporation into FE codes to simulate response of structures made of polymeric foams.

The aforementioned micro to macro scale research work is significant to help understanding the mechanical behaviour of anisotropic cellular materials, while this hierarchical research methodology is not able to directly show the cross-scale relationship between the macro-scale behaviour and micro-scale constituents. The second session of this seminar will introduce a newly developed monolithic method for concurrent multiscale analysis of heterogeneous materials, i.e., direct finite element square (FE2) method. Different from traditional multiscale modelling methods which generally require programming specific control scripts to exchange information between micro and macro scales, direct FE2 method directly connects the micro-scale RVE to the macro-scale elements using multiple points constraints (MPCs), a commonly used feature in most FE software. This not only eases the numerical implementation of multiscale analysis of heterogeneous materials, but also significantly increases the computational efficiency. These advantages enable the direct FE2 method to be a promising approach for commercial multiscale analysis in either academia or industry.

邀请单位：黄淮学院建筑工程学院