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Design Tool for Topological Optimization of Air-Platform Structural Components made by Additive Manufacturing

Description:

 
 

TECHNOLOGY AREA(S): Air Platform, Materials/Processes, Weapons

ACQUISITION PROGRAM: PMA-280 Tomahawk Weapons System; FNC: FY17 FNC titled: Quality Metal Additive Manufacturing

OBJECTIVE: Develop an integrated structural and material design tool that can exploit the benefits of Additive Manufacturing to produce novel designs for future weapon, target drone and unmanned air vehicle (UAV) structural components that cannot be fabricated by current methods.

DESCRIPTION: Increasingly complex aerospace components are limited by current manufacturing methods such as machining wrought forms, various forming, casting, and welding. Additive manufacturing (AM) can be used to fabricate complex components for use in naval aviation with the potential to enhance operational readiness, reduce total ownership cost, and enable parts-on-demand manufacturing. Future weapons, target drones and UAVs could benefit from the increased design freedom, supply chain efficiency, reduced material utilization and reduced energy consumption associated with AM technology. These factors are technology adoption “drivers” rated “high” for the aerospace industry [1]. Complex topologically optimized part designs (e.g., within today’s automotive industry) that are a challenge to fabricate by current manufacturing methods can be made more easily with free form fabrication by AM equipment. Air-platform components such as fins, wings, and uniquely shaped ducts are examples of components that are ideally suited to AM.

A currently fielded missile wing, for example, consists of a ribbed-frame structure with skin bonded to its upper and lower surface. The frame is machined from a solid plate of aluminum alloy weighing more than ten times that of the 30-pound finished part. Through AM, material utilization can be reduced over 90 percent and the overall environmental impact and carbon footprint would be substantially decreased. The business case for using AM versus current manufacturing methods improves with decreasing size of production lots [2], which is typical of many contracts to procure weapons, target drones and unmanned air vehicles.

This topic will focus initially on wings and fins because the aerodynamically contoured shapes of these air-platform parts make them more challenging to fabricate using conventional methods. However, the ability to expand the tool’s scope to include similar small parts such as stabilizers, rudders, flaps, ailerons, and winglets on UAVs should be considered as well. This topic is initially limited to use of AM processed aluminum or titanium alloys to develop an integrated structural and material design tool to support the manufacturing of these components more efficiently and with less cost. Significant work is ongoing [2] or being proposed in the areas of property definition, process qualification and certification for this process dependent manufacturing method, but defining AM properties for some process specific components remains a technical challenge. The proposed tool will be useful to designers during conceptual and preliminary design stages when component size, weight, performance and cost tradeoffs are being evaluated. To achieve this goal, an innovative methodology is needed to conduct part design and fabrication tradeoffs with an adequate degree of confidence using a total systems approach. An adequate level of confidence means that in a tradeoff between the AM-based design from this tool and an alternate conventional design, a similar level of confidence exists to enable a choice between the two options. Analytical “models” that characterize the AM material and process factors need to be developed and integrated with existing structural design tools (e.g. ANSYS [3]) used for topological optimization. The tool’s ability to exploit the unique benefits of the AM trade space to produce lighter, stronger and less-expensive parts will enhance transition of this tool to the aerospace industry.

PHASE I: Develop and demonstrate the feasibility of a topological design tool for additively manufactured air-platform components such as wings and fins in order to reduce component size, weight, count and cost while meeting key performance criteria associated with the part design undertaken to include but not be limited to fatigue, aerodynamics, shock and vibration.

PHASE II: Develop and demonstrate the design tool into existing analysis and design tools. Demonstrate its utility by designing, fabricating and testing an air platform prototype component such as a wing or fin.

PHASE III DUAL USE APPLICATIONS: Perform final design modifications and final testing. Transition the integrated structural and material design tool for additively-manufactured air platform components to initial use supporting the conceptual and preliminary design activities during the development of a next generation air platform. Private Sector Commercial Potential: Additive manufacturing (AM) is utilized throughout commercial industry for prototype development and part production. This innovative analytical design tool would have applicability to the automotive, commercial aviation, and other industries seeking to increase design freedom and supply chain efficiency and reduce material utilization and energy consumption.

REFERENCES:

  • Hart, John (2015). Additive Manufacturing. Massachusetts Institute of Technology Lecture 2.810. Retrieved from http://web.mit.edu/2.810/www/files/lectures/lec9-additive-manuf-2015.pdf
  • Frazier, W.E. (2014). Metal Additive Manufacturing: A Review. DOI: 10.1007/s11665-014-0958-z, ASM International, JMEPEG 23:1917–1928
  • Fritsch, M. (2012). An Integrated Optimization System for ANSYS Workbench Based on ACT. FE-DESIGN Optimization Inc. Chicago USA, Presentation at the 2012 Automotive Simulation World Congress

KEYWORDS: Additive Manufacturing; Structure; Air Platform; Affordability; Complex Geometry; Design

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