Evaluation of Carbon Fiber Reinforced PEEK for Utilization with a Centrifugal Compressor

Abstract Small turbine engines are efficient, reliable, and versatile and used in many different facets within the aerospace realm. Analogous to other turbine engines, large or small, decreasing the weight of these systems is always beneficial. A small turbine engine often consists of a single stage impeller. These compressor components are often in relatively low thermal environments since they are within the cold section of the engine. This invites the opportunity to use alternative materials while under relevant temperatures and test conditions. One material specifically, polyether ether ketone (PEEK), is lightweight, has good mechanical performance, and has resistance to moderately high temperatures with operating temperature up to 249°C. The typical commercial off the shelf (COTS) impellers are manufactured with an aluminum alloy and this can be seen in a simple engine, like a JetCat engine. Replacing this with PEEK enables a decrease in weight by 50% due to the density being roughly half of an aluminum alloy’s density. PEEK often has glass fiber or carbon fiber (CF) infused into it allowing an increase in strength, improvement of tribological performance, and improvement in thermal conductivity. In this paper, a chopped CF PEEK filament was used to 3D print both specimens and impellers to observe tensile, fatigue, and geometric results. This research found 3D printed CF PEEK is roughly 60% compared to the technical data sheet and will increase to 90% if fibers are aligned in the direction applied stress. Simulation stresses were higher than the ultimate strength using obtained tensile test results.