Cost effective manufacturing process of thermoplastic matrix composites for the traditional industry: the example of a carbon-fiber reinforced thermoplastic flywheel

Composite materials were successfully introduced and are now widely used for aerospace applications. Due to their high specific strength and stiffness, polymer-based composite materials should also be attractive candidates for many products of the traditional industries such as gas turbines, oil industry, or water and gas piping. The introduction of composite materials in the traditional industry is however a very slow process. Many factors can be identified as possible reasons such as the lack of previous examples on which to assess the durability of such composite products or reparability issues. However, the major factor hindering a broader use of composite materials for traditional products remains cost. Unlike the case of the aerospace industry, the use of composite materials is often not an enabling technology for traditional products: steel designs can be modified in order to increase the current product limitations. Therefore, the price of the composite system should be competitive when compared to the price of the equivalent system based on traditional materials such as steel or aluminum. In order to illustrate this concept, the case of steel risers for deepwater oil production is shortly discussed in the introduction of the present paper. When trying to reduce the price of composite products, the challenge often lies in lowering the manufacturing cost. The present paper focuses on applied manufacturing methods for various parts and products aiming to reduce cost. The associated performance of hot pressing and winding of short fiber and continuous fiber reinforced thermoplastic (AS4/PEEK) are compared for a high-speed flywheel type of application. Based on the mechanical performance and ease of fabrication, conclusions are drawn on a promising area of further investigation.