Purpose

Continuous fiber-reinforced thermoplastic composites are a class of materials highly valuable for structural applications and modeling of heat transfer within them is critical to the design of their processing methods. However, the fiber reinforcement leads to highly anisotropic thermal conduction. Among a variety of methods to account for anisotropic thermal conductivity, continuum models with effective media approximation thermal conductivity are computationally efficient and require minimal data to begin modeling a specific composite material. The purpose of this study is to evalute the utility of these models.

Design/methodology/approach

In this work, six potential effective media approximation models are evaluated against experimental heating data. Thick (>25 mm) glass fiber-reinforced polyethylene terephthalate glycol (PET-G) specimens with 40% fiber volume fraction were heated with embedded resistance heating to produce validation and testing data sets. A two-dimensional finite-difference solver was implemented using each of the six effective media approximation models. The accuracy of each model is compared.

Findings

The model developed by Cheng and Vachon was found to predict the experimental results most accurately. Fit statistics were similar in the testing and validation data sets. This model is recommended for simulation of transient heating in continuous fiber-reinforced thermoplastic composites with low-to-moderate fiber volume fractions.

Originality/value

There are a wide variety of mathematical models for effective media approximation thermal conductivity, though very few have been applied to continuous fiber-reinforced thermoplastic composites. This work shows that the simplest methods based on rules of mixtures are well outperformed by more modern and complex models, and should be incorporated for accurate prediction of heating during thermal processing of fiber-reinforced thermoplastic composites.

中文翻译：

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连续纤维增强热塑性层压板中各向异性有效导热系数理论模型的评价

 目的

连续纤维增强热塑性复合材料是一类对于结构应用非常有价值的材料，其内部传热建模对于其加工方法的设计至关重要。然而，纤维增强导致高度各向异性的热传导。在考虑各向异性热导率的各种方法中，具有有效介质近似热导率的连续体模型在计算上效率很高，并且需要最少的数据来开始对特定的复合材料进行建模。本研究的目的是评估这些模型的效用。

设计/方法/方法

在这项工作中，根据实验加热数据评估了六种潜在的有效介质近似模型。纤维体积分数为 40% 的厚 （>25 mm） 玻璃纤维增强聚对苯二甲酸乙二醇酯 （PET-G） 样品通过嵌入式电阻加热加热，以产生验证和测试数据集。使用六个有效介质近似模型中的每一个实现了二维有限差分求解器。比较每个模型的准确性。

 发现

发现 Cheng 和 Vachon 开发的模型最准确地预测了实验结果。拟合统计量在测试和验证数据集中相似。建议将此模型用于模拟具有中低纤维体积分数的连续纤维增强热塑性复合材料中的瞬态加热。

 原创性/价值

用于有效介质近似热导率的数学模型多种多样，但很少有数学模型应用于连续纤维增强热塑性复合材料。这项工作表明，基于混合物规则的最简单方法被更现代和更复杂的模型所超越，并且应该用于准确预测纤维增强热塑性复合材料热加工过程中的加热。