| Since 2003, the CCHP has been watching on a new flexible injection process. To spread the resin and to obtain a fast impregnation of the reinforcement, this new process consists on the injection of a compaction fluid in the upper cavity mould. In the bottom cavity, the reinforcement is placed and the resin is injected. All experimentations, described in this work, are done on a simple rectangular shape mould (125/375 mm) especially made for flexible injection. The upper part of the mould is in clear acrylic, witch lets us see the entire injection and by using this method information like the flow speed of resin can be extracted more accurately.; The objective of this new process is to be competitive with the RTM process ("Resin Transfer Moulding"). This process, widely used in composite manufacture, is a good reference to estimate the productivity of the flexible injection process. Works on mats reinforcement have already been done. Nevertheless, within the industrial framework, the logical follow-up is to determine the new process capacities on woven fabric. One objective of this memoire is to decrease the injection times, however the main objective is to understand and to master the process behaviours using woven reinforcement. The noted observations will show us that the quality of impregnation is crucial.; After to present mains results of past works, the chapter 4 will describe an impregnation radically different with woven fabric, this way resin will flow above the reinforcement. The remainder of the memoire focuses on ways to improve the impregnation of fabrics. Chapters 5 and 6 will attempt to prove that the upper cavity thickness and the injected resin quantity have a great impact on dry spots, and that an optimum cavity thickness and a minimum fiber volume fraction seem to be necessary to obtain good composites. Chapter 7 describes the importance of vacuum pressure of the injection cavity, which appears very important. Dry spots can be eliminating by increasing vacuum pressure. However, it does not change the kind of impregnation and resin accumulation can appear. Finally, a study on compaction fluid viscosity has been done in chapter 8, witch show us the great membrane influence. |
