Description:
TECHNOLOGY AREA(S): Chem Bio_defense, Materials, Weapons
OBJECTIVE: Leverage advancements in rapid prototyping technologies such as 3-D printing to develop innovative, cost effective, short lead time manufacturing method(s) for small production run, complex test articles of aerospace quality structural metal alloys without affecting the material properties of the subject materials.
DESCRIPTION: Seek low cost, short lead time manufacturing method(s) which can ultimately produce full and scaled threat surrogate targets of structural metal alloys with the same material properties as the identical target produced by traditional precision machining methods. One of the key system performance assessments required for all Department of Defense weapon systems is a determination that the system can negate the threat it is designed to negate. For hit-to-kill ballistic missile defense systems, missile defense systems, this lethality testing is generally performed by launching high speed interceptor surrogates into threat surrogates which can be tested at various facilities. Traditionally these “one-off” (small production run) targets have been custom-built from level 3 engineering drawings or computer assisted design (CAD) files in precision machine shops. This traditional process often results in lead times of several years and significant per unit target costs. Of key concern, is whether the rapid prototyping process can produce the metal alloys with the same material properties as the machined metals. For missile defense scenarios where the targets will be subject to high strains and high strain rates, it is imperative that the targets exhibit the same structural response as the structures they are representing. Without this assurance of equivalent material properties, the target could not provide confidence in weapon system performance against an actual threat. Material properties of interest include density, elastic modulus, critical fracture tension, and flow stress as a function of strain rate. Offerers should detail how they will use the Phase I period to determine the manufacturing method they will use and what process control is required in order to produce the correct material properties.
PHASE I: Develop an innovative manufacturing method of producing threat surrogate targets for missile defense lethality testing and demonstrate, using at least one structural metal alloy that the method can produce a testable object with the same material properties of a machined object. Produce test specimens and perform both quasi-static and split Hopkinson Bar tests for structural metal alloy.
PHASE II: Demonstrate the ability to produce the other metal alloys with the appropriate material properties via the same standard tension test used in Phase I. Develop appropriate test matrix for testing at a high strain rate. The high strain rate material properties of the novel manufacturing articles should match the existing data for those alloys within 15 percent. Demonstrate the ability to produce larger, more complex targets by manufacturing multiple quarter and full-scale targets. The results of these tests will be compared to existing test data sets for identical machined test articles. Provide technical analyses of the expected capabilities, costs, and time lines for using the rapid prototyping process. Provide technical analysis of actual manufactured items demonstrating the capability of the process to produce structural metal alloy test articles with the appropriate material properties.
PHASE III: Lower the cost of the government live fire test and evaluation test series by manufacturing various structural metal alloys and portions of the required full and quarter scale targets. Investigate the use of the rapid prototyping process for use in producing flight quality articles. This technology would benefit any industry which requires low cost, short lead time, and low rate production of structural metal alloy articles with the same materials properties as articles produced by traditional machining methods. This could include high pressure vessel production, aerospace vehicle parts, automotive parts, industrial equipment, etc.
REFERENCES:
1: Wang, Williams, Colegrove, and Antonysamy. 2013. "Microstructure and Mechanical Properties of Wire and Arc Additive Manufactured Ti-6Al-4V." Metallurgical and Materials Transactions A; 44A: p 968-977.
2: Hu and Kovacevic. January 2003. "Sensing, modeling and control for laser-based additive manufacturing." International Journal of Machine Tools and Manufacture; Vol. 43: Issue 1.
3: Pal, Patil, Zeng, and Stucker. 2014. "An Integrated Approach to Additive Manufacturing Simulations Using Physics Based, Coupled Multiscale Process Modeling. "Journal of Manufacturing Science and Engineering; 136(6): p 061022.
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6: Meyers. 1994. "Dynamic Behavior of Materials." John Wiley and Sons, New York.
7: Defense Acquisition University Web Portal for Additive Manufacturing: https://acc.dau.mil/AM.
8: Frazier. 2014. "Metal Additive Manufacturing: A Review." Journal of Materials Engineering and Performance; 23 (6): p 1917-1928.
9: Vilaro, Colin, and Bartout. 2011. "As-fabricated and Heat-Treated Microstructures of the Ti-6Al-4V Alloy Processed by Selective Laser Melting." Metall; Trans. A., 42A: p 3190-3199.
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KEYWORDS: Rapid Prototyping, Additive Manufacturing, Structural Metal Alloys, Low Rate Production, High Strain-rate Material Properties
