SBIR-STTR Award

This proposal is to develop and demonstrate a concept for a light-weight/lower-cost integrated process for producing TMC aircraft engine LP shafts. Such shafts will significantly benefit propulsion systems of advanced fighter aircraft like the JSF. The proposed integrated process will reduce the weight of a TMC JSF type LP shaft by approximately 30% relative to TMC shafts produced with the current TMC manufacturing approach and result in a final shaft (with nickel alloy ends) that is 20% to 25% lighter than the current nickel alloy shaft. The proposed approach integrates advances in TMC design, tooling, assembly and processes to use a pre-consolidated (green) arrangement of fibers and matrix that is nearer to the net shape of the post-consolidated part and incorporates more positive separation of the silicon carbide fibers than is provided by the current approach. Process and tooling modeling and preliminary development show feasibility for the concept. Phase 1 will develop the concept, perform analyses and conduct subscale testing to demonstrate its feasibility. Modeling and simulation will guide the direction. Phase 2 will provide detailed analytical derivations and prototypical device demonstrations and will develop a technology transition plan for future systems and commercial ventures. The effort will establish an improved integrated process for the production of titanium matrix composite reinforced LP shafts. Shafts produced by the integrated process will have lower weight and be less costly than shafts produced with current TMC approaches and be significantly lower weight than an all nickel base alloy shaft. A TMC shaft has great potential for improving engine performance and will be applicable in the aerospace and automotive commercial markets because they provide high stiffness and low weight along with greater flexibility for engine configuration modification. The potential for dramatic weight savings, on the order of 70%, are possible when new engines are designed that take advantage of the TMC material's attributes.

Titanium matrix composite LP shafts have large potential benefits. However, the high torque of current engines requires that oriented fiber TMC shafts have a wall thickness greater than normally considered manufacturable. A Phase I program addressed an innovative approach for (1) integrating shaft design, tool design and shaft processing, (2) manufacturing a nearer to net shape material arrangement and (3) designing with improved TMC performance-prediction and process models. TMC process development was conducted and specimens produced and tested to assess nearer to net shape fabrication. A Phase II follow-on program is proposed to enhance the manufacturing process, scale up hardware and refine modeling techniques. Phase II objectives are: (1) refine the performance and process modeling, (2) fabricate and test TMC specimens to provide statistical data for model correlation, (3) ruggedize the Phase I near net shape manufacturing process and resolve TMC thick wall issues by fabricating and testing thick wall parts and (4) utilizing the near net shape fabrication process, produce and test a TMC thick wall prototypical shaft barrel to demonstrate payoff. Based on the Phase I preliminary performance prediction model, a oriented fiber shaft barrel design can provide 28% lower weight, 19% higher stiffness and 22% higher frequency.

Keywords:
Shaft, Tmc, Reduced Weight, High Stiffness, Performance Model, Process Model, Integrated Process, Thick Wall