Browse Topic: Materials

Items (64,626)
This study proposes a multi-mode switching control strategy based on electromagnetic damper suspension (EMDS) to address the different performance requirements of suspension systems on variable road surfaces. The working modes of EMDS are divided into semi-active damping mode and energy harvest mode, and the proposed mode switching threshold is the weighted root mean square value of acceleration. For the semi-active damping mode, a controller based on LQR(Linear Quadratic Regulator) was designed, and a variable resistance circuit was also designed to meet the requirements of the semi-active mode, which optimized the damping effect relative to passive suspension. For the energy harvest mode, an energy harvest circuit was designed to recover vibration energy. In order to reduce the deterioration of suspension performance caused by frequent mode switching in the mode switching strategy, as frequent system switching can lead to system disorder, deterioration of damping effect, and
Zeng, ShengZhang, BangjiTan, BohuanQin, AnLai, JiewenWang, Shichen
ABSTRACT Rubber tracks are now extremely competitive for vehicles up to 50 tons and fully fielded on 39 ton vehicles. They represent the best of what technology can offer for tracked vehicles, in terms of high durability, performance and low life cycle cost. This is mainly attributed to the optimization through the five (5) technological tools described in this paper. Better from its numerous distinctive advantages, rubber tracks can be adapted to suit virtually any specific need. This ductile rubber track technology can be shaped to match today’s requirements, with the help of advanced rubber compounding and computer simulations
Marcotte, Tommy
ABSTRACT The authors studied the effects of different types of armor on the performance of spin-torque microwave detectors (STMD). Working prototypes of novel nano-sized spintronic sensors of microwave radiation for battlefield anti-radar and wireless communications applications are being integrated into Sensor Enhanced Armor (SEA) and Multifunctional Armor (MFA) and tested in SEA-NDE Lab at TARDEC. The preliminary theoretical estimations have shown that STMD based on the spin-torque effect in magnetic tunnel junctions (MTJ), when placed in the external electromagnetic field of a microwave frequency, can work as diode detectors with the maximum theoretical sensitivity of 1000 V/W. These STNO detectors could be scaled to sub-micron size, are frequency-selective and tunable, and are tolerant to ionizing radiation. We studied the performance of a STMD in two different dynamical regimes of detector operation: in well-known traditional in-plane regime of STMD operation and in recently
Bankowski, ElenaMeitzler, ThomasPesys, Tomas
ABSTRACT Flash® Bainite Processing employs rapid thermal cycling (<10s) to strengthen commercial off the shelf (COTS) steel sheet, plate, and tubing into Ultra Hard 600 Armor, High Hard 500 Armor, and advanced high strength steel (AHSS). In a continuous process, induction technology heats a narrow segment of the steel cross section in just seconds to atypically high temperature (1000-1300°C). Quenching substantially immediately follows. A report by Benet Labs and Picatinny Arsenal, investigating a less mature flash technology in 2011, surmised that the novel flash bainite process for steels has the potential to reduce cost and weight while also enhancing mechanical performance [1]. Receiving five financial grants, the US Dept of Energy has greatly matured flash technology in the last few years and its metallurgical understanding in collaboration with Oak Ridge National Lab and others. DOE has named Flash Bainite as the “SBIR Small Business of the Year” in May 2018 and awarded a Phase 3
Cola, Gary M
ABSTRACT Thermal management systems (TMS) of armored ground vehicle designs are often incapable of sustained heat rejection during high tractive effort conditions and ambient conditions. The use of a latent heat energy storage system that utilizes Phase Change Materials (PCMs) is an effective way of storing thermal energy and offers key advantages such as high-energy storage density, high heat of fusion values, and greater stability in temperature control. Military vehicles frequently undergo high-transient thermal loads and often do not provide adequate cooling for powertrain subsystems. This work outlines an approach to temporarily store excess heat generated by the transmission during high tractive effort situations through use of a passive PCM retrofit thereby extending the operating time, reducing temperature transients, and limiting overheating. A numerical heat transfer model has been developed based around a conceptual vehicle transmission TMS. The model predicts the
Putrus, Johnathon P.Jones, Stanley T.Jawad, Badih A.Schihl, Peter
ABSTRACT Additive/Abradable Powder Coatings (AAPC’s) are field proven, thick, solid film graphite coatings that wear in to the ideal functional geometry of mechanical components. Lubed or dry, devices lap in and run with minimized clearance and friction for highest efficiency, quietest operation, and longest life in sandy environments. AAPC’s will improve military readiness, reduce sustainment costs, and cut components logistics and fuel consumption. Processing is easy, robust and effective on new and used components in prototyping, production and remanufacturing. Worn components can be restored in theater to achieve durable, ‘better than new’ performance levels. Applications include turbos, IC pistons, lube pumps, hydraulics, roots blowers, screw compressors, refrigerant compressors, lip seal seats, and others. This paper will focus on the AAPC benefits observed on pistons and turbo compressor housings
Suman, Andrew
ABSTRACT Tracks and wheels are some of the top constituents of ground vehicle mobility and sustainment cost. Even small improvements in performance parameters and support strategies can go a long way. Analyzing equipment sustainment models can help identify these opportunities in conjunction with maintaining a situational awareness of R&D activities. Specifically, understanding component failure analysis, characterizing production road wheel material properties, conducting component testing, and benchmarking diverse manufacturing capabilities provides a roadmap to establishing and identifying “Best in Class” road wheel materials. Establishing and executing an R&D compounding plan to deliver 5X-10X durability improvement is hypothesized. Leveraging the Defense Mobility Enterprise (DME) and its authority under the 10 USC 2370 Section 845 Ground Vehicle Systems Other Transaction Agreement will allow the government to rapidly determine the technical feasibility of realizing such colossal
Patria, Garett S.Rescoe, StuBradford, WilliamMynderse, James A.
ABSTRACT At the onset of the Second World War, it was noticed that equipment being shipped overseas to the frontlines arrived corroded. The Department of Defense rapidly escalated the use of corrosion inhibitors in packaging materials to reduce the severity of the corrosion of those assets. This paper provides an overview of vapor corrosion inhibitors, describes how they are incorporated into anti-corrosion covers, and summarizes field test results showing typical protection provided to Department of Defense assets. The paper describes the environmental conditions that warrant the use of anti-corrosion covers and presents independent ground vehicle focused return-on-investment analysis. Citation: David J. Sharman, Robert R. Danko, Bill Scheible, “Light-weight drapable anti-corrosion covers,” In Proceedings of the Ground Vehicle Systems Engineering and Technology Symposium (GVSETS), NDIA, Novi, MI, Aug. 15-17, 2023
Sharman, David JDanko, Robert R.Schieble, Bill
ABSTRACT Laser powder bed fusion (LPBF) additive manufacturing often results in defective parts due to non-uniform temperature distribution during fabrication. To mitigate this issue, the authors recently introduced SmartScan, an intelligent method that employs modeling and optimization to generate scan sequences that improve temperature uniformity. However, the previous version of SmartScan could only be applied to single layers. This paper presents an extension of SmartScan to three-dimensional parts by adjusting the thermal model and optimization objective. Through simulations and experiments involving fabricating AISI 316L stainless steel parts, the study demonstrates that the proposed SmartScan approach significantly improves temperature uniformity, reduces part distortion, and mitigates residual stress, as compared to conventional heuristic sequences. Citation: C. He, C. E. Okwudire, “Scan Sequence Optimization for Reduced Residual Stress and Distortion in PBF Additive
He, ChuanOkwudire, Chinedum E.
ABSTRACT The armor research and development community needs a more cost-effective, science-based approach to accelerate development of new alloys (and alloys never intended for ballistic protection) for armor applications, especially lightweight armor applications. Currently, the development and deployment of new armor alloys is based on an expert-based, trial-and-error process, which is both time-consuming and costly. This work demonstrates a systematic research approach to accelerate optimization of the thermomechanical processing (TMP) pathway, yielding optimal microstructure and maximum ballistic performance. Proof-of-principle is being performed on titanium alloy, Ti-10V-2Fe-3Al, and utilizes the Hydrawedge® unit of the Gleeble 3800 System (a servo-hydraulic thermomechanical testing device) to quickly evaluate mechanical properties and simulate rolling schedules on small samples. Resulting mechanical property and microstructure data are utilized in an artificial intelligence (AI
Lillo, ThomasChu, HenryAnderson, JeffreyWalleser, JasonBurguess, Victor
Abstract Line2Line’s patented abradable powder surface coatings are a mechanism by which clearance between mating components is reduced, and the tribological properties of the interacting surfaces can be improved. The following discussion presents the modeling efforts targeting the numerical analysis of abradable powder piston skirt coatings. This study employs the Cylinder-Kit Analysis System for Engines (CASE) by Mid-Michigan Research to model the performance enhancements offered by abradable powder coatings as applied to piston skirts. Two piston models were generated for the purposes of this analysis, one with the post-run stock reference geometry and coating, as supplied by the manufacturer, and the second having the Line2Line post-run coated geometry. The pistons modeled had been installed within two separate Cummins R2.8 L turbo diesel engines, both of which were subject to several hours of runtime. The primary finding of the current study is that the Line2Line abradable powder
Nicklowitz, DanielSchock, HaroldSuman, AndyLowe, JimWood, Ai LeGrande
ABSTRACT Friction stir welding is a solid state joining technique in which no melting of the metals is involved. The technique is very attractive for aluminum alloys due to the low heat input involved in the process, which leads to improved mechanical properties as compared to conventional fusion welds. In this work, different aluminum series alloys were friction stir welded together. The aluminum alloys consisted of a solid solution/strain hardened aluminum alloy 5083-H131, and precipitation strengthened aluminum alloys 2139-T8 and aluminum 7085-T721. The joint combinations were aluminum alloys 5083-H131 to 7085-T721, aluminum alloys 2139-T8 to 7085-T721, and aluminum alloys 5083-H131 to 2139-T8. Their mechanical properties were analyzed and compared to base metal properties. Optical microscopy was used to analyze the grains in the welds. Good mixing of the different aluminum alloys was optically observed in all of the welds, which lead to good joint properties, opening the
Martinez, NelsonMcDonnell, Martin
ABSTRACT Most studies conducted on friction stir welded (FSW) Al alloys are on plates that are 2.5-7 mm thick. However, the U.S. Army utilizes materials that are 25 mm thick and greater for structure and armor. In order to properly apply FSW to Al-Cu-Mg-Ag alloys for use in next generation ground vehicles, data must be generated and available for model and simulation databases. One key type of data is the tensile-creep behavior of FSW AA 2139-T8. Creep is the time dependent, plastic deformation of a material under a constant load, usually observed at a constant temperature where T>0.3Tm. The objective of this study is to provide information regarding the tensile-creep behavior of the stir zone in comparison to the heat affected zone (HAZ) through the depth of the weld. The results from this research provide information on the effect of FSW processing on the microstructure and creep behavior. Pre- and post-deformation samples were analyzed via SEM and TEM and the results are discussed
Okeke, UchechiBoehlert, Carl
Related to traditional engineering materials, magnesium alloy-based composites have the potential for automobile applications and exhibit superior specific mechanical behavior. This study aims to synthesize the magnesium alloy (AZ61) composite configured with 0 wt%, 4 wt%, 8 wt%, and 12 wt% of silicon nitride micron particles, developed through a two-step stir-casting process under an argon environment. The synthesized cast AZ61 alloy matrix and its alloy embedded with 4 wt%, 8 wt%, and 12 wt% of Si3N4 are subjected to an abrasive water jet drilling/machining (AJWM) process under varied input sources such as the diameter of the drill (D), transverse speed rate (v), and composition of AZ61 composite sample. Influences of AJWM input sources on metal removal rate (MRR) and surface roughness (Ra) are calculated for identifying the optimum input source factors to attain the best output responses like maximum MRR and minimum Ra via analysis of variant (ANOVA) Taguchi route with L16 design
Venkatesh, R.
ABSTRACT Rubber is the main element of tires and the outside layer of tracks. Tire and track heating is caused by hysteresis effects due to the deformation of the rubber during operation. Tire temperatures can depend on many factors, including tire geometry, inflation pressure, vehicle load and speed, road type and temperature and environmental conditions. The focus of this study is to develop a finite element approach to computationally evaluate the temperature field of a steady-state rolling tire and track. The 3D thermal analysis software Radtherm was applied to calculate the average temperature of tread and sidewall, and the results of Radtherm agreed with ABAQUS results very well. The distributions of stress and strain energy density of the rolling tracks were investigated by ABAQUS as well. The future works were finally presented
Tang, TianJohnson, DanielLedbury, EmilyGoddette, ThomasFelicelli*, Sergio D.Smith, Robert E.
ABSTRACT The primary focus of this effort is to evaluate the roof liner technology’s ability to reduce the head injury criteria (HIC) and head acceleration to mitigate vertical impact related injures to mounted crew injures which may occur during top and bottom threat events. In an effort to reduce the likelihood of head injury during top and bottom threat attacks, an adequate roof liner is needed to reduce the force exerted on the solider. The roof liners were able to pass all system level tests. The successful system level testing confirmed the blast mat technology’s TRL-6 recommendation. Citation: J. Klima, “Developing Performance and Operating Requirements for Energy Attenuating (EA) Roof Liner for all U.S. Army Military Vehicles”, In Proceedings of the Ground Vehicle Systems Engineering and Technology Symposium (GVSETS), NDIA, Novi, MI, Aug. 10-12, 2021
Klima, Julie
ABSTRACT V-shaped hulls for vehicles, to mitigate buried blast loads, are typically formed by bending plate. Such an approach was carried out in fabricating small test articles and testing them with buried-explosive blast load in Southwest Research Institute’s (SwRI) Landmine Test Fixture. During the experiments, detailed time dependent deflections were recorded over a wide area of the test article surface using the Dynamic Deformation Instrumentation System (DDIS). This information allowed detailed comparison with numerical simulations that were performed with LS-DYNA. Though in general there is good agreement on the deflection, in the specific location of the bends in the steel the agreement decreases in the lateral cross section. Computations performed with empirical blast loads developed by SwRI and by more computationally intensive ALE methods in LS-DYNA produced the same results. Computations performed in EPIC showed the same result. The metal plate was then bent numerically so
Walker, James D.Chocron, SidneyMoore, Thomas Z.Bradley, Joseph H.Carpenter, Alexander J.Weiss, CarlGerlach, Charles A.Grosch, Donald J.Grimm, MattBurguess, Victor W.
ABSTRACT Due to the recent fluctuations in the rare-earth magnet pricing and availability demands, switched reluctance machines (SRMs) have gained significant interest to be used in automotive and military applications. SRMs are known to have high power density/efficiency, low cost, easy manufacturability, wide constant power region, robust structure and high reliability. On the other hand, high acoustic noise and torque ripple have limited their wide spread usage in the past. This paper investigates the analyses, design and experimental verification of various acoustic noise reduction techniques for SRMs. The prototypes of 100 kW SRMs for military ground vehicles have been built with the implemented acoustic noise reduction techniques and were tested using a dynamometer special for electric and hybrid vehicle testing
Sozer, YilmazTylenda, JoshuaKutz, JohnWright, Ronnie L.
ABSTRACT This paper describes the results of work performed to assess the use of corrosion product for Digital Image Correlation (DIC) measurements. DIC was recently evaluated for its capability to measure contour, strain and deflection of metals using the corrosion product instead of a painted speckle pattern. The DIC system, consisting of two cameras with zoom lenses, was set up at an angle to the specimen, enabling both cameras to image multiple sides of a specimen simultaneously. This provides a more direct measurement of in-plane and out-of-plane deformation and strains. Aluminum and steel dogbones were placed in a salt spray chamber for up to 10 days. Contour measurements were then taken at various evaluation settings as an initial assessment of the use of the corrosion product for DIC measurements. Multiple tensile tests were then performed to assess the capability of using corrosion product for strain and deflection measurements while a material is under applied load. System
Sia, Bernard
ABSTRACT Flow fields in bipolar plates of Proton Exchange Membrane fuel cells distribute fuel and oxidant over the reactive sites of the membrane electrode assembly. Bipolar plates are typically graphite with parallel or serpentine channels as flow fields. Drawbacks of graphite include weight, fabrication inaccuracy, cost, porosity, and brittleness. In this paper, open-cell metal foam is experimentally investigated as a flow field for a new bipolar plate design. Using experiments, the performance of the conventional bipolar plate/flow field was directly compared to that of the metal-foam designs at the same operational conditions. Results show that the cell current, voltage and power density were improved and temperature and pressure distribution on the membrane were even. As importantly, the conversion efficiency was higher for the metal-foam design, and the weight was reduced significantly. Citation: Nihad Dukhan, PhD, Yussef Awin, “Novel Metal-Foam Flow Fields for PEM Fuel Cells
Dukhan, NihadAwin, Yussef
ABSTRACT Ballistic validation testing typically involves firing multiple shots at a nominal velocity and ensuring the target stops every round with only partial penetrations, no completes. This testing is specified as a consequence of the binary nature of the test, and the need to meet a particular probability of penetration at a specified velocity with a certain confidence level. This legacy process has significant shortcomings owing to both the test procedures involved as well as the nature of the statistical interpretation of the results. This paper describes an alternative test and analysis procedure that produces the required level of performance and confidence information at a specified velocity, as well as the confidence over a wide range of other velocities and performance levels. In addition, this procedure eliminates many of the shortcomings associated with the legacy “no penetration” test protocol, and requires no more shots at the target. Citation: J. Eridon, S. Mishler
Eridon, JamesMishler, Scott
ABSTRACT Laser powder bed fusion (L-PBF) of entire assemblies is not typically practical for technical and economic reasons. The build size limitations and high production costs of L-PBF make it competitive for smaller, highly complex components, while the less complex elements of an assembly are manufactured conventionally. This leads to scenarios that use L-PBF only where it’s beneficial and requires integration and joining to form the final product. Today the welding process requires complex welding fixtures and tack welds to ensure correct alignment and positioning of parts for repeatable results. In this paper, both L-PBF and milled weld preparations are presented to simplify Tungsten inert gas (TIG) welding of rotationally symmetrical geometries using integrated features for alignment and fixation. All welds produced in this study passed the highest evaluation group B according to DIN 5817. Citation: Ole Geisen, Tad Steinberg, “Microstructure analysis of TIG welded additively
Geisen, OleSteinberg, Tad
ABSTRACT The open-cell metal foams have an internal structure is a web of connected ligaments. Foams are made from pure or alloys of aluminum, nickel, steel, magnesium, titanium and copper. In addition to being light weight, the foams exhibit excellent stiffness-to-weight ratios. Some foams can be resilient materials in harsh environments and have high impact resistance. The foams have high conductivities and large surface area per unit volume. All of these attributes make metal foam an attractive core for heat exchange. For example, cooling of power electronics and for thermal management of ground vehicles can employ metal-foam designs. Numerical simulation of convection heat transfer due to airflow inside commercial aluminum foam is conducted in a commercial numerical package. For validation, actual air temperatures were locally measured inside heated commercial aluminum foam, and cooled by forced air flow using a specially-developed technique. Good agreement between the modeling and
Dukhan, NihadSULEIMAN, AHMED S.AL-RAMMAHI, MUNTADHER A.
ABSTRACT For this particular effort, the U.S. Army Tank Automotive Research Development and Engineering Center (TARDEC) Center for Systems Integration (CSI) was tasked to develop a buoyancy/survivability kit that would serve multiple functions. The underbody kit would meet or surpass current required protection levels. Plus the kit was to ensure that the LAV-25A2 (Light Armored Vehicle) continues to meet the swim requirement. However, the overarching objective is to meet the survivability, ground mobility, and water mobility requirements. Combining the accomplishments in the TARDEC & PM-LAV (Program Manager for the Light Armored Vehicle) survivability program in 2013-2014 with the TARDEC & PM-LAV buoyancy/survivability kit developed in 2015-2016, the overall weight is decreased, water mobility is improved, and survivability is significantly improved. This is a unique challenge as a combination of buoyancy, mine blast, and structural requirement on a ground military vehicle is novel
Capouellez, JamesVunnam, MadanKhatib-Shahidi, BijanTison, NathonLee, In-HoDunbar, PatrickHelsel, FloydKerr, SteveHarowitz, Jack
This paper explores the groundbreaking applications of plasma propulsion engines and advanced nanomaterials in low-altitude aircraft, addressing the challenges and recent technological advancements that make such applications feasible. Traditional space plasma thrusters operate effectively in near-vacuum conditions by taking advantage of the ease of plasma ignition at low pressures. However, these thrusters face significant difficulties when operated at near-atmospheric pressures found in low-altitude environments, where plasma ignition is challenging. This paper highlights recent breakthroughs in high-pressure plasma glow discharge technology and the integration of nanomaterials, which together enable the use of plasma propulsion engines in low-altitude aircraft. These innovations offer substantial advantages over conventional engines, including higher efficiency, reduced emissions, and the potential to fundamentally change the propulsion systems of low-altitude aircraft
Ma, XinDing, ShuitingPan, YilunLiu, JinshuoQiao, HuizheYang, Jincai
ABSTRACT When the components of a military vehicle are designed, consideration is given to long term durability under repeated mission applications. In reality, surface and subsurface defects have always existed in weldments, forgings, and castings. These defects came from the manufacturing process or nucleated during the life of the vehicle. These defects may grow under repeated operations, resulting in ultimate failure of parts well before the design life is achieved. In such situations, a design based on crack initiation alone will not suffice, and a fracture mechanics based fatigue should also be included to predict the design life of a part accurately. In this paper a methodology is given on how to predict the available design life given the presence of defects in different parts of a military vehicle. An example will be provided with the process to demonstrate each step of the process
Porter, William De
ABSTRACT The goal of this work is to develop an efficient numerical modeling method for the structural dynamic response of hybrid electric vehicle (HEV) batteries in order to support fatigue life predictions. The dynamics of HEV battery packs are known to feature very high modal density in many frequency bands. The high modal density combined with small, random structural variations among the cells (which are unavoidable in practice) can lead to drastic changes in the structural dynamics. Therefore, it may be important to perform probabilistic simulations of the structural dynamic response with cell-to-cell parameter variations in order to accurately predict the fatigue life of a battery pack. However, the computational time for obtaining forced response results for just a single sample of parameter variations with a finite element model can be on the order of a day. One approach to overcome this challenge is to generate parametric reduced-order models (PROMs). The novel approach is
Hong, Sung-KwonEpureanu, Bogdan I.Castanier, Matthew P.
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