Foray Genevieve, Randrianalisoa Jaona Harifidy, Adrien Jerome, Maire Eric
Université de Lyon, INSA-Lyon, Université Claude Bernard Lyon 1, CNRS, MATEIS, UMR-5510, 69621 Villeurbanne, France.
Institut de Thermique, Mécanique et Matériaux (ITheMM), Université de Reims Champagne-Ardenne, Campus Moulin de la Housse, CEDEX 2, 51687 Reims, France.
Gels. 2022 Nov 10;8(11):732. doi: 10.3390/gels8110732.
Composite aerogels can include fibers, opacifiers and binders but are rarely designed and optimized to achieve the best thermal/mechanical efficiency. This paper proposes a three-dimensional X-ray tomography-based method for designing composites. Two types of models are considered: classical and inexpensive homogenization models and more refined finite element models. XrFE is based on the material’s real three-dimensional microstructure and/or its twin numerical microstructure, and calculates the effective conductivity of the material. First, the three-dimensional sample is meshed and labeled. Then, a finite element method is used to calculate the heat flow in the samples. The entire three-dimensional microstructure of a real or fictitious sample is thus associated with a heat flow and an effective conductivity. Parametric studies were performed to understand the relationship between microstructure and thermal efficiency. They highlighted how quickly a low volume fraction addition can improve or ruin thermal conductivity. A reduced set of three formulations was developed and fully characterized. The mechanical behavior was higher than 50 KPa, with thermal efficiencies ranging from 14 to 15 mW·m·K−1.
复合气凝胶可以包含纤维、遮光剂和粘合剂，但很少被设计和优化以实现最佳的热/机械效率。本文提出了一种基于三维X射线断层扫描的复合材料设计方法。考虑了两种类型的模型：经典且廉价的均匀化模型和更精细的有限元模型。XrFE基于材料的真实三维微观结构和/或其孪生数值微观结构，并计算材料的有效电导率。首先，对三维样品进行网格划分和标记。然后，使用有限元方法计算样品中的热流。这样，真实或虚拟样品的整个三维微观结构就与热流和有效电导率相关联。进行了参数研究以了解微观结构与热效率之间的关系。这些研究突出了低体积分数添加物能多快地提高或降低热导率。开发并全面表征了一组简化的三种配方。其力学性能高于50千帕，热效率范围为14至15毫瓦·米·开尔文−1。
