N101-097 TITLE: Innovative Material Design and Manufacturing Development for a Lightweight, Low-Cost, Highly Survivable Drive Shaft

TECHNOLOGY AREAS: Air Platform, Materials/Processes

ACQUISITION PROGRAM: PMA-261; CH-53K Heavy Lift; ACAT I

OBJECTIVE: Develop an innovative material solution (such as composites), design, and manufacturing process for a driveshaft that demonstrates high damage tolerance; that will be proven superior to a legacy shaft in terms of total affordability, weight, and durability for use in demanding aircraft applications.

DESCRIPTION: The primary application for this technology is to replace current baseline high speed drive shafts with a dynamically compatible, light weight, and ballistically tolerant alternative of equivalent strength and stiffness. Selected bidders are encouraged to collaborate with an original equipment manufacturer (OEM) to facilitate transition of proposed drive shaft design.

The proposed research would investigate low-cost alternative material constructions that offer improved damage tolerance, durability, and structural efficiency. The new drive system shall enable reduced acquisition and operational costs, with improved levels of maintainability and reliability. An important perquisite with the development of potentially experimental material designs is the robust manufacturing technique that realizes the vendor�s product. The proposing bidders must be able to demonstrate competence in the quality of their construction and the effectiveness of their facilities�e.g. factory floors, clean rooms, labs�especially if the design calls for an equally innovative manufacturing process.

The new shaft assembly shall possess highly controlled dimensional tolerances typical of dynamic components and also be designed with the foresight of future retrofit, and therefore minimal deviation from current baseline geometry is required. This will ensure ease of implementation into current production aircraft with minimal redesign cost with respect to integration with surrounding structure. Coefficient of thermal expansion (CTE) compatibility with the airframe, bearings, and attachment hardware is required to minimize thrust loads and simplify retrofit. Furthermore, the proposed design shall ensure drive shaft bearing durability.

It is recommended that bidders work with an OEM to ensure that the new driveshaft design integrate with the metallic couplings existing in the baseline in order to guarantee torque transmission effectiveness without strength or durability loss and meet fail-safe requirements.
Design must also demonstrate safe operation in severe thermal and dusty environments and dimensional stability along the length of the driveshaft to minimize induced loads on bearing and attachment hardware. Suppliers should demonstrate optimal configurations that ensure no thermal load build-up or stress concentrations.

Prior programs were successful (Ref. 2) in realizing the development of a composite driveshaft system. This system applied innovative architecture and Resin Transfer Molding (RTM) methods using untoughened epoxy in order to maintain precise control over the strict dimension constraints. However these concepts were not able to demonstrate adequate low velocity impact damage (LVID) and ballistic damage tolerance.

PHASE I: Develop a manufacturing approach and a conceptual design of the driveshaft to a sufficient level of fidelity to serve as basis for initial structural analysis. Demonstrate the low-cost feasibility of proposed design through a series of standard ASTM static and fatigue coupons tests to show equivalent strength and damage tolerance with reduced weight. Define and develop an approach for testing the proposed design against a current baseline design.

PHASE II: Generate preliminary structural allowable data for the proposed material construction by building risk reduction sub-elements and test articles representative of the proposed drive shaft design and conduct teardown analyses to evaluate laminate quality per plan laid out in Phase I. The proposed construction would be validated by building short, actual diameter specimens which would be subjected to static and fatigue tests, dynamic tests, and ballistic tests. It is recommended that these results be compared to existing baseline test results from an OEM to validate equivalent structural capability and dynamic response. Preliminary shaft design shall reflect refined mechanical performance and physical attributes.

PHASE III: Mature the proposed technologies to a Technology Readiness Level (TRL) 6 for transition to an actual production platform. Qualify final design of the drive shafts by mechanically testing a series of full scale test articles, including static deflection, torsion testing, pristine and defect fatigue testing, and ballistic tolerance testing.

PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: Alternative material processes for driveshaft applications have the potential to benefit the military, public, and private sectors. For example, the utilization of composites to replace metal in structure and dynamic components is becoming more popular as the private and military industries focus on improved affordability and durability. Composites offer significant weight reduction and tailored strength properties as opposed to the more traditionally used metals such as aluminum and titanium. They also offer corrosion resistance that extend the operating lifecycle and reduce maintenance and repair costs. This effort, if successful, would be valuable to any high-cycle, torque-bearing, fatigue-resistant shaft application. Alternate material designs for dynamic components can be applied to the aircraft, automotive, as well as automobile industries. Cylindrical shafts utilized in oil and gas exploration rigs at sea could also benefit. This technology could also be implemented in wind turbines used in the energy generation industry.

REFERENCES:
1. Affordable Thermoplastic Structures, American Helicopter Society, Forum 51, May 9-11, 1995, N. Caravsos, D. Orlino, and M. Pasanen.

2. Development and Qualification of Composite Tail Rotor Drive Shaft for the UH-60M, American Helicopter Society, Forum 64, April 29 - May 1, 2008, J. Garhart.

KEYWORDS: Ballistic Damage Tolerance; Driveshaft; Advanced Composites; Survivability; Weight Reduction; Affordability

** TOPIC AUTHOR (TPOC) **

DoD Notice:   Between November 12 and December 9, 2009, you may talk directly with the Topic Authors to ask technical questions about the topics. Their contact information is listed above. For reasons of competitive fairness, direct communication between proposers and topic authors is not allowed starting December 10, 2009, when DoD begins accepting proposals for this solicitation.

However, proposers may still submit written questions about solicitation topics through the DoD's SBIR/STTR Interactive Topic Information System (SITIS), in which the questioner and respondent remain anonymous and all questions and answers are posted electronically for general viewing until the solicitation closes. All proposers are advised to monitor SITIS (10.1 Q&A) during the solicitation period for questions and answers, and other significant information, relevant to the SBIR 10.1 topic under which they are proposing.

If you have general questions about DoD SBIR program, please contact the DoD SBIR Help Desk at (866) 724-7457 or email weblink.