Project Definition Statement

Technical Project Description (RPP: W15QKN-14-9-1002-RPP5, Rev1; Research Area: Survivability 15-22)

A. Abstract {Who is submitting (including subcontractors), what is the title of the proposed effort, concise statement of what will be done at a high level}

Lead Consortium Member: University of Wisconsin-Milwaukee (UWM)Subcontractors: Eck Industries (Nontraditional Defense Contractor), Oshkosh CorporationTitle of Proposal: Manufacture of Lightweight Seats, Armor and Frames from Metallic Syntactic Foams for Improved Performance and Survivability of U.S. Army Ground Vehicles (Survivability 15-22)

Metal matrix syntactic foams (MMSFs) are a new class of cellular material where hollow reinforcements are encapsulated in a metal matrix to create a porous composite. MMSFs exhibit much greater specific strength and specific energy absorption in compression than other similar porous materials, due to the strengthening effect of the hollow reinforcement. This makes them ideal candidates to reduce weight and improve performance in vehicle bumpers, frames, seats and armor.

This collaborative research and development effort between UWM, Oshkosh Corporation and Eck Industries seeks to upscale the manufacturing process to produce test and qualify MMSF filled frame components, seats and armor for use in military vehicles.

B. Identification and Significance of the Problem or Opportunity-{Purpose, Benefit to warfighter, history of problem that leads to solution}

During the Lightweight Materials Workshop (July 29-31, 2014), COL Christopher Cross, TRADOC-ARCIC, stated that the Army desires a 35-ton Combat Vehicle by 2030, which equates to a 54% weight reduction compared to current combat vehicles. These vehicle weight savings will result in a greater operational advantage for the Army, and will allow it to increase global, operational, and tactical mobility. A strategy based on the findings of the workshop[footnoteRef:1] suggests that investment in manufacturing technologies is necessary to meet these goals. [1: 2014 Lightweight Combat Vehicle S&T campaign project final technical report]

With previous U.S. Military funding (W56HZV-08-C-0716), UW-Milwaukee (UWM) has developed novel metal casting methods for lightweight, metal matrix syntactic foams (MMSFs) that can be used to improve mobility and survivability of military vehicles. MMSFs are a new class of cellular material where hollow reinforcements are encapsulated in a metal matrix to create a porous composite. These composites absorb energy due to their unique failure/fracture characteristics in comparison to other high strength materials. During compression, these materials reach a peak stress, followed by partial failure at the critical resolved shear stress resulting in shear and fracture of the hollow spheres. These spheres will continue to crush and the foam will densify over a large strain, all at a stress lower than the initial peak stress. This can allow for the design of ultra-light weight, energy absorbing materials based on a threshold stress for applications ranging from vehicle crumple zones to protect occupants from a crash to armor that can protect against a blast. These materials may also find use as low density/high strength/high stiffness sandwich cores or inserts to improve stiffness of sandwich composite beams and plates. In such a component, the skin material provides desired structural properties such as strength and ductility and the core improves stiffness and energy absorption. A small scale example of this concept is shown in Figure 1.

Figure 1 Magnesium AZ91/SiC syntactic foam encapsulated in a steel tube.A variety of matrix/hollow reinforcement combinations have been explored at the lab scale using powder metallurgy and liquid metal casting techniques. Powder metallurgy has been used with some success to produce larger industrial scale MMSF components at ~$40/lb. Casting techniques are by far the most versatile methods to produce syntactic foams and offer opportunities to reduce cost by an order of magnitude, however the methods employed at the lab scale need to be up-scaled to enable the production of prototypes. Figure 2 presents several strategies by which MMSFs may be produced by casting techniques.

Figure 2 Liquid metal casting techniques for synthesis of metal matrix syntactic foams.One strategy often employed to produce metal matrix composite components is to selectively reinforce a part in the regions requiring improved properties, such as a cylinder liner in an engine block. Figure 3 shows one example where an MMSF preform was successfully cast in place to produce an internal core in place of the rib structure in an aluminum automotive cross-member.

Figure 3 Aluminum automotive cross-member prototype casting. The initial mold core shown in (a) was modified to include an insert made of the aluminum syntactic foam (b), which was fully encapsulated in aluminum as shown in the cut-away (c)[footnoteRef:2]. [2: Kovcs, B. 2007 Herstellung und Eigenschaften Syntaktischer Metallschume mit verschiedenen Matrix- und Fllmaterialien PhD Dissertation, Technischen Universitt Bergakademie Freiberg.]

MMSFs exhibit attractive properties in comparison to other high strength porous materials that have been used in selected defense applications. Figure 4 shows an Ashby chart comparing properties measured at the lab scale for metal syntactic foams to the currently used metal foams. The materials developed at UWM (shown in green and pictured in the inset) provide the best combination of peak strength and energy absorption by weight.

Figure 4 Ashby chart comparing peak strength and energy absorption of metal foams and metal syntactic foams by weight. The inset shows 1" thick plates produced at UWM.Table 1 presents the respective amounts of energy differing materials can absorb under a threshold stress of 340 MPa. The amount of energy an Al-A206/Al2O3 syntactic foam can absorb is 100 times greater than the amount absorbed by typical aluminum, titanium and steel alloys and 10 times greater than what can be absorbed by open celled aluminum foams.

Table 1 Normalized absorbed energy comparison chartMaterialNormalized Absorbed Energy (below 340 MPa)Density (g/cm3)Energy absorbed/unit weight (J/g)

A206/Al2O3 MMSF12.338.2

Duocel foam-12%Dense 0.10500.3228.8

A2060.00912.80.29

A5083-H3430.00932.660.31

Ti6Al4V0.00584.430.11

4140 Steel0.00317.850.03

Metal matrix syntactic foams, like all composite materials are inherently tailorable to fit the needs of an application. One of the key attributes of MMSFs is the reinforcement wall thickness (t) to diameter (D) ratio. Previous studies at UW-Milwaukee have shown a trend of increasing peak strength with increasing t/D ratio of the reinforcement. The t/D ratio is directly correlated with the mechanical properties and the fracture mechanisms of the spheres. The greatest improvement in energy absorption is achieved at high volume fractions of reinforcement (50 volume percent is a practical maximum concentration). Therefore, barring changes to the reinforcement volume fraction, and matrix and reinforcement material/structure, the fracture characteristics, and the strength to weight ratio of MMSFs can be designed by altering the t/D ratio of the reinforcement. The mechanical properties of the matrix are also known to influence the peak strength of MMSFs, as higher strength alloys lead to higher peak strength.

Based on previous studies of reinforcement properties, matrix properties, volume fraction of reinforcement and resulting MMSF mechanical properties, semi-empirical models have been developed to describe their mechanical behavior in compression allowing for the optimal design of syntactic foams to meet desired mechanical properties.

The goal of this effort is to further evaluate optimum materials designed and tested in the previous studies to provide necessary design data, upscale manufacturing processes and design and produce prototypes. Further optimization of the material and manufacturing process through collaboration between the academic institution (UWM) and the industry partners (Eck Industries and Oshkosh Corporation) will result in further enhancements to the performance of the optimized prototypes.

C. Objectives {What is the expected Outcome}The main objectives of this project are to develop prototypes based on optimal MMSF compositions, and to upscale the manufacturing process to produce, test, and qualify these prototypes for use in U.S. Army ground vehicles.

Several outcomes of this work are expected including a reduction in weight of the components when compared to OEM equivalents, coupled with better performance in terms of strength/stiffness and energy absorption. This will allow for better fuel efficiency of the vehicle and allow increased armor or payload, as well as improved vehicle survivability. Given the low cost nature of manufacture, the use of these components can contribute to reducing initial cost, while the lightweight nature reduces operational and life-cycle cost.

The lower weight of the component will result in reduced mobilization cost as it will cost less to transport the vehicle to the field and, once in the field, will increase the range and lengthen the time that the vehicle can operate without refueling. Low cost metal casting methods will be investigated with the expected outcome of up to a ten-fold reduction in manufacturing costs for syntactic foams.

D. Deliverables {What will be delivered and what is the delivery schedule?}Physical deliverables to be built & delivered may include (but are not limited to) frames, seat, and armor plates. An optional deliverable of an OEM equivalent frame rail, seat and armor plate is included.

Technical deliverables will include quarterly reports, and a final technical report including a technical assessment of the material and recommendations for potential & feasible prototypes made from syntactic foams. This report will include the results of full material characterization conducted by UWM, and results of evaluation and testing of prototypes by Oshkosh Corporation.

The deliverables and delivery timeline is provided in Table 1 below.

Table 2 Deliverable ScheduleItemTypeDescription# of unitsDelivery DateNotes

1PhysicalMMSF PrototypeEx. Seat, armor, frame2Year 3, Quarter 4

2OEM or equivalent 1Year 3, Quarter 4Optional

3TechnicalQuarterly report

12Within 30 days of the end of each quarter.

4Final Technical Report1Within 60 days of project completion.

E. Tasks {Explanation of the tasks to be performed, along with possible risks and mitigation plan for those risks}Task 1: Kick-off meeting, determination of component requirements.A kick-off meeting will be held within the first 90 days of the project to include key personnel from the Government, main contractor (UWM) and Subcontractors (Oshkosh Corporation and Eck Industries) to establish user needs and customer requirements.

Task 2: Design of Material-(UWM)UWM will produce test specimens of compositions designed per requirements discussed in Task 1 based a) on proven processes and materials currently available and/or b) design based on material property modeling and simulation. Rigorous testing and characterization will be conducted to provide further design data for subcontractors.Risk: There is a possibility that previously designed materials will not meet the mechanical requirements of current military platforms. In this event alternate matrix materials/reinforcements will be investigated to increase the range of mechanical properties attainable. Task 3: Redesign of Component-(OSHKOSH)Oshkosh Corporation will select/re-design components using MMSFs developed as part of Task 2.Risk: There is a possibility that previously designed materials will not meet the mechanical requirements of current military platforms. In this event, selective reinforcement as a design strategy will be employed.

Task 4: Fabrication, process simulation-(ECK, UWM)Eck will perform necessary process simulation in collaboration with UWM and will upscale the UWM casting technology as required to produce prototypes. Large scale classification and quality control measures will be investigated by UWM to enable use of low cost raw materials.

Task 5: Manufacture of tooling-(ECK)Eck will manufacture tooling as required to produce MMSF prototypesRisk: Depending on the prototype design, tooling may require modification. This risk will be mitigated in part through thorough process simulation in Task 4.

Task 6: Fabrication of Prototypes-(ECK)Eck will produce a selected number of prototypes of each component to allow for testing and characterization by Oshkosh Corporation and UWM. Eck will produce an additional 2 prototypes to be submitted to the Government as deliverables. The total number of prototypes to be provided to the government is 6, 2 each of 3 prototypes.Risk 1: Difficulty in obtaining high quality reinforcement materials may delay fabrication of prototypes. This risk will be mitigated through activities in Task 4.

Risk 2: Casting defects may be observed as can be expected during scale up of a lab-scale process. This risk will be mitigated in part through activities in Task 4, and through employing process design methods available at Eck Industries obtained through prior experience in casting of metal matrix composites.

Task 7: Prototype Testing and Characterization-(OSHKOSH, UWM)Oshkosh corporation will perform metallurgical, mechanical and selected field testing. UWM will perform selected metallurgical and mechanical characterization to aid in design optimization.Risk: As there will be a limited number of prototypes produced, defects may play a significant role. Statistical analysis methods will be employed to help mitigate this risk.

Task 8: Preparation of Final Report-(OSHKOSH, ECK, UWM)Following testing performed in Task 7, Oshkosh, Eck and UWM will prepare a comprehensive final report which includes recommendations of any potential & feasible prototype components made from syntactic foams.

Task 9: Delivery of optimized prototypes, and OEM equivalents to Government (UWM)

F. Schedule of Events {Explanation of when the tasks will be performed, along with possible risks and mitigation plan for those risks.}Project StageActivityYear 1Year 2Year 3

Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4

ManagementProject work

InitialProject Kick-off and Planning(UWM/Eck/OSK)

Determination of Component Requirements(UWM/Eck/OSK)

DesignDesign of Material (UWM)*

Redesign of Component (OSK)*

Fabrication Process Simulations (Eck, UWM)*

PrototypingManufacture of Tooling (Eck)*

Fabrication of Prototypes (Eck)*

Prototype Testing (OSK)**

Prototype Characterization (UWM)**

FinalPreparation of final report and delivery of components(UWM/Eck/OSK)

*Additional time as required to mitigate risks as outlined in section E is shown as a darker shade of blue.** These risks as outline in section E are mitigated through the statistical methods employed.

G. Integrated Baseline {Cost tied to a timeline and broken down by tasks}Table 3 Integrated BaselineProject StageActivityYear 1Year 2Year 3Funding Required

Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4

ManagementProject work$1,800,000*

InitialProject Kick-off and Planning(UWM/Eck/OSK)*

Determination of Component Requirements(UWM/Eck/OSK)*

DesignDesign of Material (UWM)$350,000

Redesign of Component (OSK)$50,000

Fabrication Process Simulations (Eck,UWM)$50,000

PrototypingManufacture of Tooling (Eck)$50,000

Fabrication of Prototypes (Eck)$50,000

Prototype Testing (OSK)$105,000

Prototype Characterization (UWM)$225,000

FinalPreparation of final report and delivery of components(UWM/Eck/OSK)*

* Cost of these activities are included in the $1,800,000 Project Work activity as they are associated with staff salaries, fringe benefits, and overhead

H. System Design and Performance {Detailed information regarding the proposed system design and how the proposed design will meet the performance requirements stated in the RPP.}N/A, No requirement specified in RPP.

I. Testing {Detailed information regarding proposed testing and evaluation approach in order to meet the performance requirements stated in the RPP, to include a focus on the offerors testing capability and expertise relevant to evaluating the design against the performance requirements.}UWM will develop lab scale manufacturing processes for metal matrix syntactic foam compositions which can be up-scaled by the industry partner Eck Industries. Material specimens produced at UWM will be characterized via optical and electron microscopy, shear, bend, crush and impact testing according to applicable standards to assess technical feasibility of metal matrix syntactic foams developed in the lab and to provide necessary data for design by Oshkosh Corporation. Control specimens will be tested for comparison of mechanical and physical properties, and will be used as a benchmark for evaluating the mechanical properties including strength, stiffness and energy absorption. This testing will extend and build upon work previously conducted at UWM on MMSF compositions developed under previous funding (W56HZV-08-C-0716), as detailed in published studies[footnoteRef:3]. [3: J.A. Santa Maria, B.F. Schultz, J.B. Ferguson, N. Gupta, P.K. Rohatgi, Effect of hollow sphere size and distribution on the quasi-static and high strain rate compressive properties of Al-A380-Al2O3 syntactic foams, J. Mater. Sci., 49(3), (2014), pp.1267-1278. DOI: 10.1007/s10853-013-7810-y; J.A. Santa Maria, B.F. Schultz, J.B. Ferguson, P.K. Rohatgi, Al-Al2O3 Syntactic Foams Part I: Effect of matrix strength, hollow sphere size and distribution on the quasi-static compressive properties of Al-A206-Al2O3 syntactic foams, Mater. Sci. Eng. A. 582, (2013), pp. 415-422. ; J.B. Ferguson, J.A. Santa Maria, B.F. Schultz, P.K. Rohatgi, Al-Al2O3 Syntactic Foams Part II: Predicting Mechanical Properties of Metal Matrix Syntactic Foams Reinforced with Ceramic Spheres, Mater Sci Eng A, 582, (2013), pp. 423-432. ; G.A. Rocha, B.F. Schultz, J.B. Ferguson, N. Gupta, P.K. Rohatgi, "Compressive properties of Al-A206/SiC and Mg-AZ91/SiC syntactic foams," J. Mater. Res., 28, (2013), pp. 2426-2435.]

Manufacturing processes for production of prototypes (e.g. frame rails, seat components, and armor plates, as designed by Oshkosh Corporation) will be developed by Eck Industries. Eck Industries has extensive experience in developing casting tooling and processes for manufacture of metal matrix composites, and currently produces high strength structural aluminum castings for a variety of military platforms including Bradley, M113, M1 and various FCS vehicles. UWM will consult with engineers at Eck Industries to aid in the production of metal matrix syntactic foam components with desired mechanical properties. Eck Industries will produce a requisite number of castings for testing and qualification at Oshkosh Corporation, UW-Milwaukee, and the Government. UWM will take sections from the manufacture components and perform metallurgical and mechanical testing

Oshkosh Corporation will independently perform metallography/stereomicroscopy, tensile testing, impact testing, ballistic testing, fatigue testing and vehicle testing of the prototypes developed in this project. Oshkosh Corporation has extensive vehicle and subsystem/component testing capabilities.

The results of these independent studies will be provided in a final report, and will be compared to the performance of equivalent OEM components when applicable/available.

J. Software/Algorithm- {The offeror shall submit detailed information regarding their proposed approach software development in order to meet the reuqirements stated in the RPP, to include software quality, software design, software configuration control, software testing and evaluation, and software documentation.}N/A, No requirement specified in RPP.

K. Support Engineering- {The offeror shall submit detailed information regarding their proposed approach to supportability engineering to meet the requirements stated in the RPP, to include supportability, training, logistics, reliability and maintainability, human factors engineering (HFE), MANPRINT, and health and safety engineering.} N/A, No requirement specified in RPP.

L. Integration Methodology {The offeror shall submit detailed information regarding their proposed approach related to integration methodology, to include integrating developed technical components by working collaboratively with the Government to achieve the performance requirements stated in the RPP.} The proposed project involves development of processes and prototypes in collaboration with a foundry capable of meeting future department of defense production needs (Eck Industries) and a major tactical vehicle manufacturer that designs, builds and sustains high performance defense trucks (Oshkosh Corporation). Prototypes will be tested by Oshkosh Corporation under service conditions, allowing for evaluation of components for integration into Military vehicles. The proposed collaboration between UWM, Eck Industries and Oshkosh Corporation, will improve the speed at which these innovative materials can be transitioned from laboratory proof of concept, to prototype, to certified/installed component. This collaboration is advantageous as it provides a clear path for integration of the proposed prototype components in future designs meeting the performance requirements stated in the RPP.M. Supportability and Maintainability {The offeror shall submit a plan to outline the maintainability, availability, sustainability and supportability of operations related to the effort.}An integrated baseline review meeting will be held with key project stakeholders within the first 90 days of contract award which in part will establish user needs, and design criteria in greater detail then is presently available in the RPP. Prototype components will be designed by Oshkosh Corporation, under a design for support frame work with the goal to reduce total life cycle costs of the component. A supportability analysis will be performed as part of the design process as illustrated in Figure 5 below.

Figure 5 Supportability Analysis Flow Chart