Application of cellular automata and Lattice Boltzmann methods for modelling of additive layer manufacturing
Application of cellular automata and Lattice Boltzmann methods for modelling of additive layer manufacturing
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DOI：
10.1108/hff-10-2016-0418
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发表时间：
2018-01-01
影响因子：
4.2
通讯作者：
Rainforth, W. Mark
中科院分区：
文献类型：
--
作者：
Svyetlichnyy, Dmytro;Krzyzanowski, Michal;Rainforth, W. Mark
目的 - 基于元胞自动机 (CA) 和格子玻尔兹曼方法 (LBM) 的整体数值模型正在开发中，作为集成建模方法的一部分，用于研究骨科植入物激光辅助增材层制造 (ALM) 中不同物理机制的相互作用。在整体模型中考虑顺序或同时发生的几个物理事件。它们包括粉末床沉积、激光能量吸收和通过移动激光束加热粉末床，导致粉末熔化或烧结、熔池中的流体流动并流过部分或未熔化的材料，以及凝固。本研究的目的是开发一种基于 CA 和 LBM 的整体数值模型结构，适用于研究骨科植入物 ALM 中不同物理机制的相互作用。该模型应该与早期开发的基于 CA 的粉末床生成模型兼容。设计/方法/途径 - 所提到的物理事件伴随着固相和液相的传热，包括边界处的界面传热。烧结/熔化模型正在开发中，使用 LBM 作为源自晶格气体元胞自动机的流体动力学模拟的独立数值方法。它将与基于 CA 的粉末床生成模型相结合。研究结果 - 考虑到相关物理现象，整个激光辅助 ALM 过程已被分析并分为几个阶段。由四个相互关联的子模型组成的整个整体模型目前已得到不同程度的发展。这些子模型包括基于 CA 的粉末床生成模型、基于 LBM-CA 的热交换和传递模型、热固液界面模型和连续液体流动的机械固液界面模型。 实际意义 - 获得的结果可用于解释 ALM 中不同物理机制的相互作用，ALM 是金属、非金属和复合材料结构件先进制造的一个集中发展的领域，例如， 生物工程。所提出的整体模型被认为是集成建模方法的一部分，该方法被开发为一种数值工具，用于研究在移动高能热源加热粉末床期间顺序或同时发生的多物理现象之间的协作关系，导致选择性粉末烧结或熔化、熔池中的流体流动和通过部分（或未）熔化的材料以及凝固。该模型与早期开发的基于 CA 的粉末床生成模型兼容，可降低数值噪声。 原创性/价值 - 目前的结果对于研究基于选择性激光烧结或熔化的 ALM 过程中发生的多物理现象之间的复杂关系（包括流体流动和传热）而言是原创的和新的，被认为对于获得所需的性能至关重要。
Purpose - The holistic numerical model based on cellular automata (CA) and lattice Boltzmann method (LBM) are being developed as part of an integrated modelling approach applied to study the interaction of different physical mechanisms in laser- assisted additive layer manufacturing (ALM) of orthopaedic implants. Several physical events occurring in sequence or simultaneously are considered in the holistic model. They include a powder bed deposition, laser energy absorption and heating of the powder bed by the moving laser beam, leading to powder melting or sintering, fluid flow in the melted pool and flow through partly or not melted material, and solidification. The purpose of this study is to develop a structure of the holistic numerical model based on CA and LBM applicable for studying the interaction of the different physical mechanisms in ALM of orthopaedic implants. The model supposed to be compatible with the earlier developed CA- based model for the generation of the powder bed.Design/methodology/approach - The mentioned physical events are accompanied by heat transfer in solid and liquid phases including interface heat transfer at the boundaries. The sintering/melting model is being developed using LBM as an independent numerical method for hydrodynamic simulations originated from lattice gas cellular automata. It is going to be coupled with the CA- based model of powder bed generation.Findings - The entire laser- assisted ALM process has been analysed and divided on several stages considering the relevant physical phenomena. The entire holistic model consisting of four interrelated submodels has currently been developed to a different extent. The submodels include the CA- based model of powder bed generation, the LBM- CA- based model of heat exchange and transfer, the thermal solid- liquid interface model and the mechanical solid- liquid interface model for continuous liquid flow.Practical implications - The results obtained can be used to explain the interaction of the different physical mechanisms in ALM, which is an intensively developing field of advanced manufacturing of metal, non-metal and composite structural parts, for instance, in bio-engineering. The proposed holistic model is considered to be a part of the integrated modelling approach being developed as a numerical tool for investigation of the co-operative relationships between multiphysical phenomena occurring in sequence or simultaneously during heating of the powder bed by the moving high energy heat source, leading to selective powder sintering or melting, fluid flow in the melted pool and through partly (or not) melted material, as well as solidification. The model is compatible with the earlier developed CA-based model for the generation of the powder bed, allowing for decrease in the numerical noise.Originality/value -The present results are original and new for the study of the complex relationships between multiphysical phenomena occurring during ALM process based on selective laser sintering or melting, including fluid flow and heat transfer, identified as crucial for obtaining the desirable properties.