Thermoplastic Composites for the Next Generation Aerospace Structures

Continuous fiber reinforced thermoplastic composites (TPCs) have been adopted increasingly for small to medium sized aerospace components. Over the last ~15-years TPCs have been used in aircraft interior applications, then in lightly loaded brackets, through secondary structures and now in primary structure components. This has been accompanied by the transition of material systems from fabric reinforcement to unidirectional tape and from engineering polymers to high performance polymers such as poly(aryl-ether-ketones) including PEEK and PEKK. TPCs offer weight savings compared to metals and recurring part cost reduction relative to thermoset composite components. TPCs also provide performance advantages compared to thermosets including increased toughness and damage tolerance, and low flame, smoke and toxicity properties. The benefits of TPCs have been realized for small-medium sized components, typically up to 10lbs in weight. Material costs are often higher than thermosets and recurring cost savings are achieved primarily through the short fabrication cycle times and the opportunity to automate the part manufacturing processes. These aspects are realized where part count is relatively high such as standardized components which are used in large quantities, or on aircraft with high production rates. The next generation of aerospace vehicles include urban air mobility platforms, delivery drones and new single aisle aircraft, all of which will be built in relatively high volumes and can realize the benefits of high rate and high volume manufacturing using TPCs. Economic technologies are being developed for the manufacture of larger scale TPC structures using technologies such as automated tape placement (ATL) and in-situ advanced fiber placement (AFP). TPC components can assembled using welding methods with further cost and weight savings. Welded assembly is being used in a limited range of production applications and will provide significant benefits in the next generation of TPC structural assemblies.