Browse Topic: Materials properties

Items (31,688)
This foundation specification (AMS3050) and its associated category specifications (AMS3050/1 through AMS3050/9) cover anti-seize compounds for use on threads of nuts, studs, bolts, and other mating surfaces, including those of superheated steam installations, at temperatures up to 1050 °F (566 °C). Compounds containing PTFE are limited to 600 °F (315 °C) maximum. Materials for nuts, studs, bolts, and other mating surfaces include, but are not limited to: steel, nickel alloys, stainless steel, and silver-coated materials. This specification invokes the Performance Review Institute (PRI) product qualification process. Requests for submittal information may be made to the PRI at the address in 2.3.3, referencing this specification. Products qualified to this specification are listed on a Qualified Products List (QPL) managed by the PRI. Additional tests and evaluations may be required by individual equipment builders before a grease is approved for use in their equipment. Approval and/or
AMS M Aerospace Greases Committee
This specification establishes the requirements for dyed anodic coatings on aluminum alloys
AMS B Finishes Processes and Fluids Committee
This specification covers an aluminum alloy in the form of hand forgings up to 5.000 inches (127.00 mm), inclusive, in nominal thickness at the time of heat treatment, procured to inch/pound dimensions (see 8.6
AMS D Nonferrous Alloys Committee
This SAE Aerospace Information Report (AIR) summarizes data and background relative to age control of specific classes of those nitrile type synthetic elastomers used in sealing devices which are resistant to petroleum base hydraulic fluids, lubricating oils, and aircraft fuels. This includes, but is not limited to, those nitrile (NBR or BUNA-N) elastomers previously covered by Section I of MIL-STD-1523
AMS CE Elastomers Committee
This specification covers a corrosion- and heat-resistant nickel alloy in the form of bars, forgings, flash-welded rings, and stock for forging or flash-welded rings
AMS F Corrosion and Heat Resistant Alloys Committee
ABSTRACT The family of lightweight high Mn, high Al steels (FeMnAl) exhibit lower density (6.5-7.2 g/cm3) than traditional military steels (7.9 g/cm3). These alloys are precipitation hardened, with κ-carbide dominating hardening performance. This carbide has an E21 perovskite structure with a nominal composition of (Fe,Mn)3AlC. In the literature, a number of studies have examined the sensitivity of mechanical properties to changing a single element in the composition. However, the covariance of the major elements has not been systematically explored. In this study, a series of small ingots were prepared according to a two-factor design of experiments, in addition to analysis of previously generated compositions. Methods of measuring alloy composition will be discussed, along with aging kinetics and key mechanical properties. Citation: K. Sebeck, I. Toppler, K. Limmer, D. Field, D. Wagner, A. Gafner, “Compositional Sensitivity of High Mn, High Al Steels”, In Proceedings of the Ground
Sebeck, KatherineToppler, IanLimmer, KristaField, DanielWagner, DanielGafner, Alyssa
ABSTRACT Through Army SBIR funding, NanoSonic has created and empirically optimized viscoelastic HybridSil polyurethane siloxane seat cushions that provide improved pressure distribution and Multi-Axial Simulation Table (MAST) vibration dampening over currently employed Commercial-Off-The-Shelf (COTS) seat cushions. The foundation of this effort was the synthesis of novel polyurethane siloxane foams and the correlation of their copolymer composition and crosslinking density with vibrational damping, pressure distribution mapping, and mechanical properties. ASTM D 3574 mechanical testing indicates HybridSil seat cushions maintain dimensional stability after extended fatigue testing. H-point testing completed in accordance with FMVSS-202A indicates NanoSonic’s seat cushions afford comparable positional values to the current employed seat cushions and thus have direct integration potential. Citation: V. Baranauskas, H. Hutchinson, G. Litrichin, “High Performance Hybridsil Seat Cushions
Baranauskas, VinceHutchinson, McKenzieLitrichin, Gale
ABSTRACT Heavily armored vehicles contain a thick base armor, yet it is insufficient for protection against shaped charges of high explosive anti-tank warheads. Add on armors such as non-explosive reactive armors (NERA) and explosive reactive armors (ERA) have been developed to increase protection levels of armored vehicles. ERA elements are composed of plates and explosive materials. ERA requires a rugged enclosure that reduces the collateral damage during a ballistic event by controlling the effects of the ensuing blast. An attempt is made to simulate the enclosure tests and capture sandwich plate’s behaviors subjected to detonating energetic explosives by using LS-DYNA nonlinear explicit solver, widely used in simulating detonation, impact, ballistics, and other structural problems. Successful simulation of ERA enclosures will allow an evaluation of the influences of some of the parameters, such as thickness of plate and attack angle, and different materials to improve design
Babu, VenkateshVunnam, MadanKlann, Shawn C.Filar, Charles A.
ABSTRACT Additions of both carbon fiber (CF) and carbon nano-tubes (CNTs) as reinforcements to polyurea (PUr) based adhesives are computationally investigated. Both CF and CNTs show an increase in stiffness. The effect of CF reinforcements on the PUr is more pronounced than the CNT’s but this due to CNT loading being dramatically lower. On percent basis the CNT effect on strength was greater than the CF. Increasing hard segment content of PUr also had a positive effect on the joint strength, but a negative effect on the shear joint displacement. Finally the addition of CF reinforcements moved the performance of a PUr formulation from a Group IV adhesive into the Group III category. This paper illustrates the potential for commonly available reinforcements to be used to tailor the strength elongation characteristic of a PUr adhesive system. Citation: Demetrios A. Tzelepis, Robert Hart, “Optimization of Nano-Enhanced Elastomeric Adhesives Through Combined Experimental and Computational
Tzelepis, Demetrios A.Hart, Robert
ABSTRACT FeMnAlC alloys exhibit lower density (6.5-7.2 g/cm3) than traditional military steels (7.9 g/cm3) while maintaining similar energy absorption capabilities. Material substitutions in legacy systems must meet existing form/fit/function requirements, limiting opportunities for lightweighting of existing designs. This study examines production and material properties of thick plate with a nominal chemistry of 30% Mn, 9%Al and 1%C, in the wrought condition. Due to the high aluminum and carbon content, there are unique challenges to large scale (45+ ton heat) production versus typical armor steel chemistries. Lab-scale wrought and production material are characterized, comparing microstructure, and mechanical properties. Processing practices including teeming flux and rolling temperature are discussed. The high manganese content of this alloy presents challenges for welding and machining practices, such as limited compatibility of weld wires and substantial work hardening during
Sebeck, KatherineToppler, IanRogers, MattLimmer, KristaCheeseman, BryanHowell, RyanHerman, William
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 This paper reviews research that has been conducted to develop inductively assisted localized hot forming bending technologies, and to use standardized welding tests to assess the practicality and potential benefits of adopting stainless based consumables to weld both existing and evolving armor alloys. For the titanium alloy Ti6Al4V it was determined that warming the plate to circa 600°F would improve the materials ductility (as measured by reduction of area) from ~18 to 40% without exposing the material to a temperature at which atmospheric contamination would be significantly deleterious. For the commercial alloy BB and class 1 armor alloy it was found that there was little effect on the charpy impact toughness and the proof strength as a result of processing at 900 °F with either air cool or water quench and there was an added benefit of lower residual stresses in the finished bends compared to cold formed bends. Heating “alloy BB” to 1600 °F followed by water quench
Lawmon, JohnAlexandrov, BoianDuffey., MatthewNgan., Tiffany
ABSTRACT The M1 Abrams will be the primary heavy combat vehicle for the US military for years to come. Improvements to the M1 that increase reliability and reduce maintenance will have a multi-year payback. The M1 engine intake plenum seal couples the air intake plenum to the turbine inlet, and has opportunities for improvement to reduce leakage and intake of FOD (foreign object debris) into the engine, which causes damage and premature wear of expensive components
Tarnowski, StevePennala, SteveGoryca, MaryKauth, Kevin
ABSTRACT One of the main thrusts in current Army Science & Technology (S&T) activities is the development of occupant-centric vehicle structures that make the operation of the vehicle both comfortable and safe for the soldiers. Furthermore, a lighter weight vehicle structure is an enabling factor for faster transport, higher mobility, greater fuel conservation, higher payload, and a reduced ground footprint of supporting forces. Therefore, a key design challenge is to develop lightweight occupant-centric vehicle structures that can provide high levels of protection against explosive threats. In this paper, concepts for using materials, damping and other mechanisms to design structures with unique dynamic characteristics for mitigating blast loads are investigated. The Dynamic Response Index (DRI) metric [1] is employed as an occupant injury measure for determining the effectiveness of the each blast mitigation configuration that is considered. A model of the TARDEC Generic V-Hull
Jiang, WeiranVlahopoulos, NickolasCastanier, Matthew P.Thyagarajan, RaviMohammad, Syed
ABSTRACT Since the 1980s, the US Army has been successfully utilizing silicone brake fluid (SBF) to protect military ground vehicle brake systems from corrosion in a variety of environments. Currently, the US Army is focusing its ground vehicle brake system efforts on safety by executing a hardware technology upgrade to anti-lock braking systems (ABS). SBF has been purported by many ABS manufacturers to be incompatible with ABS; however, to date no literature exist to prove these claims. Therefore, the work therein investigated these claims by testing SBF versus traditional glycol-based brake fluid in a commercial ABS utilizing a pump and dump cycle approach to simulate ABS actuation. As expected, failure of SBF was observed at 20,000 cycles, while no failure was observed for the traditional fluid. The failure of SBF was investigated and identified to be related to the lower lubricity of SBF in relation to the traditional fluid, as well as SBF incompatibility with internal ABS
Schroeder, ZackerySebastian, TaliaYost, DouglasJeyashekar, NigilBramer, JillWatson, Daniel
ABSTRACT A functionally-graded NPR (Negative Poisson’s Ratio) material concept has been developed for a critical Army application – blast protection. The objective is to develop a combined computational design methodology and innovative structural-material concept for a blast-protective deflector, which can concentrate material into areas most needed and adapt its shape utilizing the blast energy to improve blast mitigation and crew protection. Included in the computational design methodology is optimal deflector shape design and optimal NPR material distribution to further improve the protection while minimizing the C.G. height of the vehicle and the weight of the deflector. Structures fabricated using this new concept react to the explosion and reconfigure themselves under the blast force to provide maximum blast protection. The presented research work consists of two basic approaches to deflector design: optimal deflector shape design and optimal NPR material configuration and
Ma, Zheng-DongBian, HongxinSun, CeHulbert, Gregory M.Bishnoi, KrishanRostam-Abadi, Farzad
ABSTRACT A newly developed structural adhesive demonstrates a unique combination of high strength (43 ± 2 MPa) and displacement (4.7 ± 1.2 mm) in aluminum lap joint testing. Bulk material characterization of the prototype adhesive reveals its extreme ductility, with nearly 80% shear strain before failure and a 2.5-fold increase in strain energy density as compared to commercial structural adhesives. The prototype adhesive is found to maintain 67 to 82% of its initial strength under extreme environmental conditions, including at high temperatures (71°C), after high humidity (63°C hot water soak, 2 weeks), and after corrosive conditions (B117 salt spray, 1000 hours). The prototype structural adhesive is shown to also generate high strength bonds with multiple substrates, including steel, carbon fiber, and mixed material joints, while also providing galvanic isolation
Pollum, MarvinKriley, JosephNakajima, MasaTan, Kar TeanStalker, JeffreyFleischauer, RichardRearick, Brian
ABSTRACT The US Army TARDEC has been researching an alternative to current armor steel that is both tough, and light-weight. The studied alloy is based on the Fe-Mn-Al-C system. This study was conducted to investigate and quantify this alloy’s susceptibility to hot cracking phenomena related to casting and welding. Very little research has been done on general weldability of this alloy system, so the results of these tests will be compared to other high Mn steels, and alloys that have undergone cast pin tear testing. Testing will be conducted utilizing button melting tests, autogenous spot welds, and cast pin tear testing. The cast pin tear testing was conducted to measure this alloys susceptibility to weld solidification cracking. The spot welds were used to quantify the susceptibility of the weld heat affected zone (HAZ) to liquation cracking, as well as to observe the solidification structure of the fusion zone. The testing results showed that the FeMnAl system in its current form
Evans, WilliamRamirez, Antonio J.Sebeck, Katherine
ABSTRACT This paper addresses candidate technologies for attaching steels to selected lightweight materials. Materials of interest here include aluminum and titanium alloys. Metallurgical challenges for the aluminum-to-steel and titanium-to-steel combinations are first described, as well as paths to overcome these challenges. Specific joining approaches incorporating these paths are then outlined with examples for specific processes. For aluminum-to-steel joining, inertia, linear, and friction stir welding are investigated. Key elements of success included rapid thermal cycles and an appropriate topography on the steel surface. For titanium-to-steel joining, successful approaches incorporated thin refractory metal interlayers that prevented intimate contact of the parent metal species. Specific welding methods employed included resistance mash seam and upset welding. In both cases, the process provided both heat for joining and a relatively simple strain path that allowed significant
Gould, Jerry E.Eff, MichaelNamola, Kate
ABSTRACT As metallic parts are used, wear, fracture, galling, warpage, and other forms of obsolescence occur. When these issues progress beyond a predefined level, the parts are either replaced or repaired. Replacement leads to undesirable logistics requirements, especially for those parts requiring difficult-to-source, expensive and/or long-lead-time materials. Repair options are often limited due to strict performance requirements of the parts or concern over the quality of the repair. Two relatively new additive manufacturing (AM) process options exist to complete repairs, including repairs required in theater. Hybrid repair via metal AM followed by precision machining within a single setup offers unique repair options not previously available. Though somewhat limited with respect to the number of alloys currently tested, hybrid AM via directed energy deposition (i.e., powder sprayed into a laser-heated liquid metal pool) offers the possibility to quickly, economically and
Sabo, Kenneth M.Golesich, Brock T.Tims, Michael L.
ABSTRACT A bainite phase-based alloy and associated thermomechanical process were developed to produce (2.5 to over 5 cm) thick armor-grade steel with uniform through-thickness high hardness and strength. The alloy composition and the final-critical (austenite to bainite) isothermal transformation step were specifically designed to utilize a simple and versatile air-cool/quench method to keep a low upfront capital cost and to provide the ability to continuously control the cooling rate in real time, in order to produce maximum volume fraction of bainite phase, and promote uniformly distributed strength and hardness. Final thickness of 1.9 cm and 5.7 cm steel plates were fabricated for characterization, testing and evaluation and found to possess uniform through-thickness hardness between 53 to 55 HRC and dynamic compressive strength of up to 2 GPa
Chu, Henry S.Lillo, Thomas M.Anderson, Jeffrey A.Zagula, Thomas A.
ABSTRACT Results are presented from tests on a formulated 15W-40 mil-spec engine/transmission fluid to examine the impact of additives on improving its reliability and durability under extreme tribological conditions. A block-on-ring (BOR) configuration was used to measure the effect of five additives (an emulsion-based boric acid, tricresyl phosphate, particulate-based boron nitride, particulate-based MoS2, and particulate-based graphite) on the critical scuffing load as a function of additive concentration and time to scuff during oil-off tests (starved lubrication). A four-ball configuration was used to evaluate the impact of simulated engine grit/sand on the abrasive wear of steel as a function of grit size and loading. The results demonstrated that the additives increased the load for scuffing by 50 to 100% for the formulated oil and by 50 to 150% for the unformulated base fluid used in the formulated oil. Two of the additives (emulsion-based boric acid and tricresyl phosphate
Fenske, G. R.Ajayi, O. O.Erck, R. A.Lorenzo-Martin, C.Masoner, AshleyComfort, A. S.
ABSTRACT Full-vehicle, End-to-End under-body blast (UBB) simulations with LS-DYNA have been common practice at the Tank Automotive Research, Development and Engineering Center (TARDEC) for the last several years to support Program Managers in the Army Acquisition of military ground vehicles. Soil, which is one of the four key components (with air, charge, and vehicle structure being the others), has been represented in these simulations by an Elastic-Plastic Hydrodynamic (EPH) model. EPH models has been available for the currently used Double-Sifted (DS) Topsoil since 2012, but not yet developed for a proposed Engineered Roadway Soil (ERS). This study describes a systematic method where EPH model fits were developed based on material characterization tests, and then validated against physical tests with two different types of large flat plates. The accuracy of this model has been shown in nine different comparisons of plate velocity (impulse) or deformation to be well within 11.3
Hsieh, ChingSheng, JianpingRamalingam, JaiAkers, StephenKorson, Chantelle
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 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 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 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 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
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