Fundamentals of thermoplastic sandwich structure fabrication using laser-based in-situ thermoplastic Automated Fiber Placement. (TheSaLab)

使用基于激光的原位热塑性塑料自动纤维铺放制造热塑性夹层结构的基础知识。

• 批准号: 524551499
• 负责人: Professor Dr.-Ing. Berend Denkena
• 金额: --
• 依托单位: Institut für Fertigungstechnik und Werkzeugmaschinen (IFW)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/524551499?language=en
• 关键词: Fundamentals; thermoplastic; sandwich; structure; fabrication

Structures made of carbon fiber reinforced plastic (CFRP) offer enormous lightweight potential due to their high specific strengths. In recent years, the trend has been moving from thermoset to thermoplastic materials in order to exploit the advantages of recyclability as well as the joining of two components by local melting of the matrix. A particularly good ratio of mechanical properties to weight is achieved by sandwich structures. The manufacture of thermoplastic sandwich structures using conventional processes is currently limited to flat sandwich structures. A few approaches for the production of three-dimensional structures require highly complex molds as well as multi-step manufacturing processes and are also limited to a single shape to be defined. Thermoplastic Automated Fiber Placement (TAFP), on the other hand, offers a flexible fiber composite manufacturing process. A comprehensive understanding of the process already exists for processes in which similar semi-finished products are used. However, there is a lack of knowledge about the mechanisms and the characteristics of the optical-thermal-mechanical interactions during the deposition of anisotropic tapes on isotropic foam structures. Preliminary investigations have shown that the formation of a cohesive bond between deposited tapes and foam core is possible in principle under TAFP process conditions. However, if unsuitable process parameters are selected, local collapse of the foam structure or insufficient cohesive bonding of the two joining partners occurs. The aim of this project is therefore to develop a fundamental understanding of the relationships between the optical and thermomechanical interactions in the heating and joining zones during the deposition of carbon fiber reinforced thermoplastic tapes on thermoplastic foam cores using laser-based TAFP. For this purpose, in a first step, the optical interaction of the laser radiation with the foam material and the prepreg tapes is investigated and the power distribution in the heating zone resulting from the reflection, absorption and transmission characteristics of the two joining partners is determined in a model-based manner as a function of the laser settings. Furthermore, the behavior of the foam and consolidation roller is mechanically characterized under process parameters and transferred to material models. The results of the investigations will then be combined and validated in a thermomechanical process model. By coupling the thermomechanical process model with a bond strength model, the influence of the process parameters on the bond quality between deposited tape layers and foam core will be explored. By generating a fundamental understanding, the basis for the fabrication of individually curved thermoplastic sandwich structures using laser-based TAFP is established.

由碳纤维增强塑料(CFRP)制成的结构由于其高的比强度提供了巨大的轻量化潜力。近年来，热固性材料的发展趋势是从热固性材料转向热塑性材料，以利用可回收利用的优势，以及通过局部熔融基质将两个组分连接在一起。夹层结构获得了特别好的机械性能与重量比。使用传统工艺的热塑性夹层结构的制造目前仅限于平板夹层结构。生产三维结构的一些方法需要高度复杂的模具以及多步骤制造过程，并且还限于要定义的单一形状。另一方面，热塑性自动纤维贴装(TAFP)提供了一种柔性纤维复合材料制造工艺。对于使用类似半成品的工艺，已经有了对工艺的全面了解。然而，在各向同性泡沫结构上沉积各向异性带材的过程中，光-热-力相互作用的机理和特征还缺乏相关知识。初步研究表明，在TAFP工艺条件下，沉积带和泡沫芯之间原则上可以形成粘结。然而，如果选择了不合适的工艺参数，泡沫结构会发生局部坍塌或两个连接伙伴之间的粘结不充分。因此，该项目的目的是对使用激光TAFP在热塑性泡沫塑料芯材上沉积碳纤维增强热塑性胶带过程中加热和连接区域中的光学和热机械相互作用之间的关系有一个基本的了解。为此，在第一步骤中，研究激光辐射与泡沫材料和预浸带的光学相互作用，并根据激光设置以基于模型的方式确定由两个连接伙伴的反射、吸收和传输特性导致的加热区中的功率分布。此外，在工艺参数下对泡沫和固结辊的行为进行了力学表征，并将其转换为材料模型。然后，研究结果将在热力学过程模型中进行组合和验证。通过将热机械过程模型与粘结强度模型相耦合，探讨了工艺参数对沉积带层与泡沫芯粘结质量的影响。通过建立一个基本的理解，为利用激光TAFP制造单独弯曲的热塑性夹层结构奠定了基础。