A virtual lab for Ni/PU hybrid foams: stochastic micromechanical identification and efficient numerical simulations

Ni/PU 混合泡沫虚拟实验室：随机微机械识别和高效数值模拟

• 批准号: 338131106
• 负责人: Professorin Dr.-Ing. Anne Jung
• 金额: --
• 依托单位: Unit in engineering science
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2020-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/338131106?language=en
• 关键词: virtual; lab; Ni; PU; hybrid

The main goal of the project is a virtual lab for open-cell metal foams that can predict macroscopic mechanical responses and their variations, based on the mesoscopic and microscopic distributions of the geometrical and mechanical parameters. A discrete mesostructural model will act as the virtual lab. It will account for variations of the strut connectivity, variations of the strut dimensions and variations of the strut material parameters. The model developments and the experimental identification of the stochastic geometrical and material parameters will be performed for a recently developed Ni/PU hybrid foams, which are substantially cheaper than alternative open-cell hybrid metal foams.The innovations in the project largely focus on experimental techniques and stochastic parameter identification. The main innovations can clearly be distinguished in four sub-aims. First, an experimental procedure to measure forces as functions of local strain fields for individual struts, as well as for several pores. Second, a 3D beam model to represent the discrete mesostructure of metal foams will be developed. The beam model will serve as the virtual lab and will account for variations by employing a Monte Carlo based approach, in which numerous realisations of the stochastic parameters are made. Single struts will be represented by series of 1D beams. The 1D beam formulation will be geometrically nonlinear and able to predict the elastoplastic response of single struts. The full 3D beam model will furthermore be able to predict failure of individual struts and deal with strut-to-strut contact (beam-to-beam contact). Furthermore, an inverse modelling procedure using Bayesian Inference will be used to identify the distributions of the material parameters of single struts, when they are modelled by a series of beams. Bayesian Inference ensures a consistent approach to treat the material parameters as stochastic, and not deterministic, variables. Finally, the 3D beam model (i.e. the virtual lab) will be validated based on experimental results at the mesoscale (several pores). The strut connectivity and strut dimensions of the samples must be known in detail for this. Therefore, both factors must be expliciteöy determined.A successful project will result in a full 3D beam model able to account for stochastic effects in the foams structure to improve the prediction of the macroscopic foams behaviour by numerical simulations.

该项目的主要目标是一个开孔金属泡沫的虚拟实验室，可以根据几何和力学参数的介观和微观分布预测宏观力学响应及其变化。一个离散的细观结构模型将作为虚拟实验室。它将考虑支柱连接的变化、支柱尺寸的变化和支柱材料参数的变化。本文将对一种新型的Ni/PU混杂泡沫金属材料进行随机几何参数和材料参数的模型开发和实验识别，该材料比其它开孔混杂金属泡沫材料便宜得多，本项目的创新点主要集中在实验技术和随机参数识别上。主要的创新可明显区分为四个次级目标。首先，一个实验程序来测量力的函数的局部应变场的个别支柱，以及为几个孔。其次，将开发一个三维梁模型来表示泡沫金属的离散细观结构。梁模型将作为虚拟实验室，并将通过采用基于蒙特卡罗的方法，其中许多实现的随机参数的变化。单个支柱将由一系列1D梁表示。一维梁公式将是几何非线性的，并能够预测单支柱的弹塑性响应。此外，完整的3D梁模型将能够预测单个支柱的失效，并处理支柱与支柱的接触（梁与梁的接触）。此外，逆建模过程中使用贝叶斯推理将被用来识别的分布的材料参数的单个支柱，当他们被一系列的梁建模。贝叶斯推断确保了将材料参数视为随机变量而非确定性变量的一致方法。最后，3D梁模型（即虚拟实验室）将根据中尺度（几个孔隙）的实验结果进行验证。为此，必须详细了解样品的支柱连接性和支柱尺寸。因此，这两个因素都必须明确地确定。一个成功的项目将产生一个完整的3D梁模型，能够解释泡沫结构中的随机效应，从而通过数值模拟改善宏观泡沫行为的预测。