ABSTRACT

Throughout the past, heating by electromagnetic induction has been frequently used to design speedier curing processes of adhesives. With this method, bonded components are exposed to an alternating electromagnetic field (EMF), which generates heat in EMF-sensitive adherends, like steel and aluminium, or in susceptors that are admixed to the polymers to be cured, e.g. fibres or particles. Recently, specially designed susceptors, so-called Curie particles (CP), have shown their great potential for induction curing. Heat generated in CP is capped by the materials Curie temperature (T_c), preventing the adhesive from overheating. As a result, curing proceeds way faster and independently from ambient temperatures, opening up new application fields for bonded components. Although practical applicability has already been demonstrated, CP-induced heating – and consequently curing – has proven to be very sensitive to the boundary conditions of the considered application. Therefore, induction times needed to achieve full cure must currently be determined by cumbersome and costly experimental investigations. To compensate for this disadvantage, the present study – representing the second part of a series – aimed at offering a first approach of a numerical model in which thermal and kinetic aspects of CP-induced accelerated curing were combined. For that, curing kinetics of two kinetically different 2K epoxy adhesives were linked to a transient heat flow simulation in Ansys based upon experimentally determined heat loads. Since the first part of this series concentrated on presenting all preliminary experimental work as well as analytics applied during modelling, this part focuses on the validation of the developed FEA using the exemplary application of CP-cured Glued-in Rod (GiR) specimens. In the following, various numerical parameter studies were carried out, demonstrating principal functionality of the new FEA technique and highlighting in particular its contribution for the design of more efficient and target-orientated CP-curing processes.

摘要

在过去，通过电磁感应加热经常被用于设计更快的粘合剂固化过程。使用这种方法，粘合的组件会暴露在交变电磁场 (EMF) 中，这会在对 EMF 敏感的被粘物（如钢和铝）中或在与待固化聚合物混合的感受器中产生热量，例如。纤维或颗粒。最近，专门设计的感受器，即所谓的居里粒子 (CP)，已显示出其在感应固化方面的巨大潜力。CP 中产生的热量受材料居里温度 ( T _c)，防止粘合剂过热。因此，固化进行得更快，并且不受环境温度的影响，为粘合组件开辟了新的应用领域。尽管已经证明了实际适用性，但 CP 引起的加热 - 并因此固化 - 已被证明对所考虑应用的边界条件非常敏感。因此，目前必须通过繁琐且昂贵的实验研究来确定实现完全治愈所需的诱导时间。为了弥补这一缺点，本研究（代表系列的第二部分）旨在提供数字模型的第一种方法，其中结合了 CP 诱导的加速固化的热和动力学方面。为了那个原因，两种动力学不同的 2K 环氧树脂粘合剂的固化动力学与 Ansys 中基于实验确定的热负荷的瞬态热流模拟相关联。由于本系列的第一部分集中介绍了所有初步实验工作以及建模过程中应用的分析，因此本部分重点介绍了使用 CP 固化胶合棒 (GiR) 试样的示例性应用对开发的 FEA 的验证。接下来，进行了各种数值参数研究，展示了新 FEA 技术的主要功能，并特别强调了它对设计更有效和面向目标的 CP 固化工艺的贡献。由于本系列的第一部分集中介绍了所有初步实验工作以及建模过程中应用的分析，因此本部分重点介绍了使用 CP 固化胶合棒 (GiR) 试样的示例性应用对开发的 FEA 的验证。接下来，进行了各种数值参数研究，展示了新 FEA 技术的主要功能，并特别强调了它对设计更有效和面向目标的 CP 固化工艺的贡献。由于本系列的第一部分集中介绍了所有初步实验工作以及建模过程中应用的分析，因此本部分重点介绍了使用 CP 固化胶合棒 (GiR) 试样的示例性应用对开发的 FEA 的验证。接下来，进行了各种数值参数研究，展示了新 FEA 技术的主要功能，并特别强调了它对设计更有效和面向目标的 CP 固化工艺的贡献。