Computational homogenisation for modelling heterogeneous multi-phase materials

该项目旨在开发一种强大而新颖的计算模拟工具，用于预测复杂材料的大尺度（宏观）响应。特别是这个项目是关于模拟的材料是不同的或不均匀的性质（异质）。除了固体之外，这些材料还可以包含液体和/或气体的区域为了理解和模拟暴露于外力和内力、加热和/或干燥的这种材料的大规模响应，有必要识别和模拟在小尺度下材料内部发生的基本物理过程传统上，工程师和科学家通过模拟材料的观测响应来描述材料的大尺度行为，而不参考基本过程或材料成分。所提出的分析工具的目的是通过模拟在小尺度上发生的过程来间接地描述大尺度响应。然而，任何试图对大规模问题的每个材料细节进行建模的尝试都是不现实的，因此材料的每个区域都将由现实的小规模描述来表示。然后将该代表性部件对载荷的响应按比例放大到大尺度。该项目将扩展适用于纯机械行为的现有放大技术，以包括与热和质量（液体和气体）传输过程的耦合。这种技术将允许模拟受到极端环境条件（例如加热（例如火））的固体，以及占据材料中的空隙的液体和/或气体的影响。此外，研究将考虑这些过程如何随着材料成分的变化而变化。还将采用模拟材料界面和断裂的新技术，拟开发的模拟框架将适用于一大类异质材料（例如水泥复合材料、生物组织、岩石、土壤、金属复合材料和植物材料），如果不考虑较小尺度下发生的复杂过程，就无法解释这些材料的大尺度行为。

This project aims to develop a powerful and novel computational simulation tool for predicting the large-scale (macroscopic) response of complex materials. In particular this project is concerned with the simulation of materials that are diverse or non-uniform in nature (heterogeneous). In addition to the solid, these materials may also contain regions of liquid and/or gas (multi-phase).In order to understand and simulate the large scale response of such materials that are exposed to external and internal forces, heating and/or drying, it is necessary to identify and simulate the underlying physical processes that are taking place inside the material at a small scale (micro-scale) and to take account of the complex nature of the structure of the material at this small scale.Traditionally, engineers and scientists have described the large-scale behaviour of materials by simulating their observed response without reference to the underlying processes or material composition. The proposed analysis tool aims to describe the large-scale response indirectly by simulating the processes that are taking place at the small scale. However, any attempt to model every material detail of a large scale problem is unrealistic and therefore each region of the material will be represented by a realistic small-scale description. The response of this representative part to loading will then be scaled up to the large scale. In this way the large-scale response of the material is simulated by processes that are taking place at the smallscale.This project will extend existing upscaling techniques that are applicable to purely mechanical behaviour to include coupling with heat and mass (liquid and gas) transport processes. Such a technique will permit the simulation of solids subject to extreme environmental conditions, such as heating (e.g. fire), and the effect of liquid and/or gas that occupy voids in the material. Furthermore, the research will consider how these processes change as the material composition changes. New techniques for modelling material interfaces and fractures will also be adopted.The modelling framework to be developed will be applicable to a large class of heterogeneous materials (e.g. cementitious composites, biological tissues, rocks, soils, metal composites and vegetative materials) whose large-scale behaviour cannot be interpreted without consideration of the complex processes occurring at smaller scales.