Development of a process characterization unit for composites molding

聚合物复合材料在交通、航空、航海、体育等行业的应用持续增长。在过去的20年里，由于“液体复合材料模塑”(LCM)的使用，随着制造成本的降低，复合材料在大型零件上的应用越来越多。在LCM制造中，液体反应性聚合物树脂通过包含在封闭模具中的碳纤维或玻璃纤维增强体注射。这些高质量和低成本的工艺符合无排放有害溶剂的环境要求。这些过程涉及几个复杂的现象，如树脂流动、纤维浸渍、树脂固化、热变化和流变性，使LCM对工艺参数非常敏感。选择合适的制造条件(即温度、压力或树脂配方)通常是一个基于用户知识的微妙决定。 该项目旨在开发一种能够测量关键工艺参数的新型表征单元。当聚合物树脂已经通过纤维增强浸渍时，该装置将允许快速识别材料特性，例如聚合物树脂的热和固化动力学特性。然后可以在标准模拟软件中使用这些特性来优化制造条件。要开发这样的表征单元，必须考虑几个因素，如聚合物的化学反应能力、夹具的热行为、纤维增强体的致密性等。同时，必须建立物理方程，以便从测量的热信号中提取所需的参数。 这样的表征单元将有助于快速识别关键材料性能和在线优化工艺条件。这一单元将是对工业应用的RTM制造进行更全面分析的第一步。拟议的五年项目将从表征单元的设计、数据采集系统和控制软件的开发开始。实验和工业验证将在项目结束时进行。

The application of polymer composite materials is continuously growing in several markets including transportation, aeronautical, nautical and sport industries. The application of composite materials for large parts has increased the last 20 years as manufacturing costs decrease thanks to the usage of "Liquid Composite Molding" (LCM). In LCM manufacturing, a liquid reacting polymer resin is injected through a carbon or glass fibrous reinforcement contained in a closed mold. These high quality and low cost processes meet the environmental requirements of emission free harmful solvents. These processes involve several complex phenomena such as resin flow, fiber impregnation, resin cure, thermal and rheological variations that make LCM very sensitive to processing parameters. Selecting proper manufacturing conditions (i.e., temperature, pressure or resin formulation) is a delicate decision often based on user's knowledge. This project aims to develop a novel characterization unit capable of measuring key process parameters. This unit will allow quick identification of material properties such as thermal and cure kinetics properties of the polymer resin when already impregnated through the fibrous reinforcement. These properties can then be used in standard simulation software to optimize the manufacturing conditions. To develop such a characterization unit, several factors must be considered such as polymer chemical reactivity, the thermal behavior of the fixture, the compaction of the fibrous reinforcement, etc. In parallel, physical equations have to be developed in order to extract the required parameters from the measured thermal signal. Such a characterization unit will help in quickly identifying key material properties and in on-line optimization of processing conditions. This unit will constitute a first step towards a more comprehensive analysis of RTM manufacturing for industrial applications. The proposed five years project will start by the design of the characterization unit, data acquisition system and development of the control software. Experimental and industrial validation will be carried out at the end of the project.