Browse Topic: Tests and Testing

Items (23,908)
ABSTRACT Ground vehicle mobility in soft soil is crucial to many military missions. Thus, it has been tested and quantified in a metric called Vehicle Cone Index (VCI) since World War II. VCI provides an index of the minimum soil strength necessary for vehicle mobility. The standard operating procedure for VCI field testing and data analysis is detailed herein. Also, a new method for quantifying VCI uncertainty has been proposed, which uses confidence bounds on mean measurements of soil strength. A sample analysis of actual field data is provided
Stevens, Maria T.Towne, Brent W.Osorio, Javier E.Mason, George L.
The fixed-wing VTOL is a new type of aircraft that combines the advantages of multi-rotor and fixed-wing aircraft. Enable freely taking off and landing, while maintaining high flight speeds during cruising. However, higher requirements for the powertrain system have emerged. The powertrain needs to adapt to the layout of distributed propulsion devices while also ensuring sufficient endurance. Both the full-electric powertrain and traditional fuel-based powertrain are unable to meet this demand, making the hybrid-electric powertrain one of the most feasible solutions currently available. A 10kW level hybrid-electric powertrain system was designed for a fixed-wing VTOL aircraft. The power generation performance tests are conducted to analyze the coupling working characteristics of the engine and generator. The performance of the hybrid configuration and the full-electric configuration in terms of power-to-weight ratio, energy-to-weight ratio, and endurance are compared. The results
Yanan, LiLi, HaiwangXie, GangSun, Mohan
In this paper, a single-chip based design for an automotive 4D millimeter -wave radar is proposed. Compared to conventional 3D millimeter-wave radar, this innovative scheme features a MIMO antenna array and advanced waveform design, significantly enhancing the radar's elevation measurement capabilities. The maximum measurement error is approximately ±0.3° for azimuth within ±50° and about ±0.4° for elevation within ±15°. Extensive road testing had demonstrated that the designed radar can routinely measure targets such as vehicles, pedestrians, and bicycles, while also accurately detecting additional objects like overpasses and guide signs. The cost of this radar is comparable to that of traditional automotive 3D millimeter-wave radar, and it has been successfully integrated into a forward radar system for a specific vehicle model
Cai, YongjunZhang, XianshengBai, JieShen, Hui-LiangRao, Bing
ABSTRACT For most standards bodies, the validation and maturation process is dependent on motivated members of the standards community to develop reference systems or components and to provide the governing body with the necessary data and details to support maturing a given specification or set of specifications. Although this has worked well for other standards bodies, the VICTORY Standards Support Office (VSSO) recognized early that validation would be key in rapidly defining usable specifications for the Army ground vehicle community. Understanding the importance of validating specifications, the VSSO formally defined a validation process that is used to aid in maturing the VICTORY Standard Specifications. This paper will focus on explaining the formalized validation process that is applied to the VICTORY Standard Specifications
Dennis, DoyleSaylor, KaseWilliams, NikiaSiddapureddy, VenuFairburn, Brian
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 The U.S. Army has been pursuing vehicle electrification to achieve increased combat effectiveness and new capabilities, potentially requiring high power pulse duty cycles. However as Energy Storage System (ESS) pulse power discharge rates (> 40 C rate) increase, there is a significantly lower ESS lifetimes. Results of high power pulse duty cycles on lithium iron phosphate cell lifetime performance show a dramatic loss. For 2s and 3s, 120 A pulse tests, the observed degradation after 80 hours cycling is 22 % and 32 % respectively, significantly higher than previously reported values at lower discharge rates, but similar temperatures. A 7 year calendar aged cell was also tested with a 2s pulse and showed severe degradation (53% loss after 40 hours cycling). The decreased lifetime of the high pulse duty cycling aged cells is a result of the increased strain / heating at high currents, and subsequent SEI fracture, and thermally accelerated SEI formation. This mechanism leads to
Thampan, TonyDing, YiToomey, Laurence
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 This paper describes the role of Modeling and Simulation (M&S) as a critical tool which must be necessarily used for the development, acquisition and testing of autonomous systems. To be used effectively key aspects of development, acquisition and testing must adapt and change to derive the maximum benefit from M&S. We describe how development, acquisition and testing should leverage and use M&S. We furthermore introduce and explain the idea of testable autonomy and conclude with a discussion of the qualities and requirements that M&S needs to have to effectively function in the role that we envision. Citation: J. Brabbs, S. Lohrer, P. Kwashnak, P. Bounker, M. Brudnak, “M&S as the Key Enabler for Autonomy Development, Acquisition and Testing”, In Proceedings of the Ground Vehicle Systems Engineering and Technology Symposium (GVSETS), NDIA, Novi, MI, Aug. 13-15, 2019
Brabbs, JohnLohrer, ScottKwashnak, PaulBounker, PaulBrudnak, Mark
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 An important aspect of any new ground vehicle acquisition program is an analytic understanding of the key performance, cost, risk and growth tradeoffs inherent with the system design. The Whole System Trades Analysis Tool (WSTAT) provides a holistic framework for modeling and understanding these tradeoffs. In this paper, we present the overarching WSTAT methodology and then consider a specific implementation for the Army’s Squad Multipurpose Equipment Transport (SMET) autonomous ground vehicle. Emerging results regarding high-level SMET design considerations are provided to demonstrate the types of decision support enabled by the WSTAT capability
Henry, Stephen M.Waddell, Lucas A.DiNunzio, Michael R.
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 As the penetration levels of unmanned ground vehicles (UGV) in military applications increase, there is a growing need to evaluate their mobility across different latencies and various modes of operation ranging from pure teleoperation to full autonomy. State-of-the-art tools to evaluate mobility of ground vehicles do not address this need due to their not accounting for UGV technologies and the associated latencies. Although the trade-off between latency and performance has been thoroughly studied in the telerobotics literature and the results may qualitatively shed light onto the UGV domain, as well, a quantitative generalization is not possible due to the differences in context. Recognizing this gap, this paper presents a functional relationship between mobility and latency in high-speed, teleoperated UGVs under the context of path following. Specifically, data from human-in-the-loop simulations performed in this paper are combined with data from prior studies to span three
Cole, Michael P.Crean, Cory M.Gorsich, David J.Jayakumar, ParamsothyJain, AbhinandanErsal, Tulga
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 Acceptance testing is considered a final stage of validation, and performing acceptance tests of an actual UGV system can be expensive and time-consuming. Therefore, this paper discusses simulation based acceptance testing for UGVs, which can significantly reduce the time and cost of the acceptance test. In this paper, both dynamic and static simulation models are developed, and the results from these simulations show that the static simulation can be used, rather than the more complex dynamic simulation, because of the slow operating speed of UGVs. This finding improves the development efficiently at the simulation model development phase. In addition, the developed simulation models provide a better understanding of the UGV failure modes. The static simulations can determine the required joint motor torques for various UGV loadings and maneuvers and provide data for the full range of operating motion. Specifically, given threshold joint torque value, the safe operating range
Lee, Hyo JongJin, Jionghua (Judy)Ulsoy, A. Galip
ABSTRACT The U.S. Army has been pursuing vehicle electrification to achieve enhanced combat effectiveness. The benefits include supporting new capabilities that require high power pulse duty-cycles. These pulse power discharge rate can be significantly higher than commercial Hybrid Electric Vehicle (HEV) Energy Storage Systems (ESS) systems, resulting in significantly lower lifetimes than commercial applications. Results of high power pulse duty cycles on lifetime performance are presented as well as a discussion on the cause of degradation. Citation: T. Thampan, Y. Ding, L.Toomey, A. Hundich, V. Babu, “Accelerated degradation of Li-ion Batteries for High Rate Discharge Applications”, In Proceedings of the Ground Vehicle Systems Engineering and Technology Symposium (GVSETS), NDIA, Novi, MI, Aug. 13-15, 2019
Thampan, TonyDing, YiToomey, LaurenceHundich, AlexBabu, Venkatesh
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 Fuel filters used to remove particulates from liquids are evaluated by OEM’s and filter manufacturers using standardized test protocols that specify simplified conditions that aid in laboratory reproducibility. These test results do not always translate into actual filter performance in application. In military vehicles that experience frequent demands for rapid acceleration and deceleration and extreme vibration, the importance of evaluating fluid filtration performance with these parameters as inputs is significant. This paper discusses an investigation of the performance sensitivity of a diesel particulate filter to structural vibration properties and flow rate fluctuation. After determination of this sensitivity to dynamic inputs, a new test protocol was developed for evaluating competitive fuel filters. The cyclic flow and mechanical vibration inputs for the new protocol were selected to be representative of those that would be seen in a heavy duty diesel application
Hollingsworth, LarryWostarek, PeterExposito, Christian
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 Standard requirements for directed energy deposition (DED) additive manufacturing (AM) of parts were needed for a new NAVSEA Technical Publication. DED procedure qualification schemes were developed for integrated and non-integrated build platforms and for both single-sided and double-sided build applications. A double-sided build platform approach is widely preferred for distortion control and build productivity. These procedure qualification requirements were developed for arc, laser, and electron beam welding-based DED processes using wire or powder consumables. Each procedure qualification scheme included a standard qualification build (SQB) design, nondestructive evaluation test map, property specimen test matrix and qualification records for each application and process combination. Since these metal AM processes cover a range of feature size capabilities that are defined by minimum deposit bead width, SQBs were designed for full-scale (~> 5 mm), sub-scale (~2 – 5 mm
Harwig, D.D.Mohr, W.Kapustka, N.Hay, J.Carney, M.Hovanec, S.Handler, E.Farren, J.Rettaliata, J.Hayleck, R.
ABSTRACT Due to shortcomings in vehicle mobility prediction in the NATO Reference Mobility Model (NRMM), recommendations and requirements for the Next-Generation NATO Reference Mobility Model (NG-NRMM) are under development. The limiting nature of empirically based terramechanics and the recent decades of significant improvements to 3D physics based Modeling and Simulation (M&S) capability call for a process to quantify physics based M&S in meeting the proposed goals of NG-NRMM. A verification and validation (V&V) process is demonstrated to quantify the vehicle mobility prediction capability of current state of the art physics based M&S tools. The evaluation is based upon an M&S maturity scale adopted and modified from corporate simulation governance to fit the specifics of vehicle mobility. The V&V process is demonstrated through a set of benchmarks, one for a tracked and another for a wheeled vehicle. The NG-NRMM benchmark efforts have demonstrated an analytical process for
Balling, OleMcCullough, MichaelHodges, HenryPulley, ReidJayakumar, Paramsothy
ABSTRACT An experimental testing program has been developed that looks to optimize the battery recharging algorithms to improve battery lifetime and state of charge knowledge. The first phase of the testing targeted lead acid battery performance characterization as a function of controlled environmental temperatures. Subsequent testing includes performance testing under alternator recharging using default and proposed charging algorithms. A new experimental apparatus has been developed to integrate battery testing with alternator charging to simulate in-vehicle operations under controlled environmental conditions. Results are presented for the baseline performance testing, a model is presented for the characterization of battery parameters and a description of the test apparatus and approach employed for the integrated alternator testing is included
Jones, StanleyMendoza, JohnWang, DanielDing, YiZanardelli, Sonya
The advent of the low-altitude economy represents a novel economic paradigm that has emerged in recent years in response to technological advancement and an expanding social demand. The low-altitude economy is currently undergoing a period of rapid development, which underscores the importance of ensuring the safety of airfield operations. To enhance operational efficiency, unmanned aerial vehicles (UAVs) can be utilized for the inspection of the surrounding area, runway inspection, environmental monitoring, and other tasks. This paper employs TurMass technology, the TurMass gateway is miniaturised as the communication module of FT24, and the TK8620 development board replaces the LoRa RF module in the ELRS receiver to achieve the communication transmission between the remote control and the receiver. Additionally, a TurMass chip is integrated into the UAV to transmit beacons, while an airfield management aerial vehicle is employed to receive nearby UAV data, thereby preventing
Zhang, XiaoyangChen, Hongming
ABSTRACT Operating safely in cluttered environments is critical to future autonomous robotic operations as exemplified by FCS Risk 213. In support of this requirement, the Robotics Collaborative Technology Alliance (RCTA) program, sponsored by the Army Research Lab (ARL), has supported research tasks and corresponding integration and test events from 2006 through 2009. Multiple sensor systems, including scanning LADARs and stereo camera pairs, have been used to detect, track, and predict the future motion of obstacles in the close proximity of unmanned ground vehicles. These sensors produce frames of data at rates ranging from 6 to 30 Hertz. Resulting algorithm outputs are correlated to the local world and detection results both above and below the thresholds of the individual algorithms are recorded in a common format. This paper describes two methods for fusing the detection data. The first is a simplistic approach which implements a majority voting scheme amongst the algorithm
Haley, Paul H.Thornton, Susan M.Mitchell, Robert R.Zachar, William P.Hoffelder, MikeMcLean, Steven
ABSTRACT A discussion on the utility of physics-based compact thermal models to guide the design, integration, operation and control of thermally sensitive vehicle components is presented. Effective component selection requires honest and accurate representation of the key performance attributes expressed by physics-based models. Parallel developments and lessons learned from the Electronics Industry on component packaging and characterization is discussed. An example application of a physics-based model driven design is presented for an Electrical Energy Dissipater design used on typical hybrid vehicles. Low fidelity models are used early in the design to support system requirements decomposition into discreet design attributes. High fidelity thermal and electromagnetic models are used to explore the design space and to optimize performance metrics. Accurate and robust reduced order thermal models are used for the continuous prognostic, diagnostic monitoring and control of the device
Kassinos, AdonisLippsmeyer, JeffreyWebb, Steven
ABSTRACT This paper will discuss via case study both military and civilian hybrid vehicle development focusing on the processes required from the selection of the hybrid propulsion system architecture, component down-selection using advanced modeling and simulation tools, body/chassis development and integration, design verification testing using an advanced dynamometer test facility, and final full vehicle validation on the test track. The paper will incorporate results from the FED (Fuel Efficiency Demonstrator) program where AVL is responsible in collaboration with World Technical Services Inc., for delivering a fully developed hybrid propulsion system integrated into the demonstrator vehicle
Deweerdt, ThomasLiao, Gene
ABSTRACT Accurate models of operator workload in highly automated ground vehicles could inform interface design decisions, predict performance impacts of new systems, and evaluate existing systems. This paper summarizes an existing methodology for modeling human operator workload, demonstrates its application to automated ground vehicles, and discusses its value in development, certification, and acquisition of autonomous military ground systems
Pop, Vlad L.Michelson, W. Stuart
ABSTRACT Localization refers to the process of estimating ones location (and often orientation) within an environment. Ground vehicle automation, which offers the potential for substantial safety and logistical benefits, requires accurate, robust localization. Current localization solutions, including GPS/INS, LIDAR, and image registration, are all inherently limited in adverse conditions. This paper presents a method of localization that is robust to most conditions that hinder existing techniques. MIT Lincoln Laboratory has developed a new class of ground penetrating radar (GPR) with a novel antenna array design that allows mapping of the subsurface domain for the purpose of localization. A vehicle driving through the mapped area uses a novel real-time correlation-based registration algorithm to estimate the location and orientation of the vehicle with respect to the subsurface map. A demonstration system has achieved localization accuracy of 2 cm. We also discuss tracking results
Stanley, ByronCornick, MatthewKoechling, Jeffrey
ABSTRACT This paper focuses on development of methods for manufacturing structural thermoplastic composite materials, characterizing the mechanical properties of such composites, and modeling the static and dynamic performance in relevant military vehicle modeling and simulation environments. A thermoplastic polyethylene terephthalate (PET) / fiberglass composite was selected for this study due to the high specific strength of e-glass fibers, the high toughness of the PET thermoplastic, and relatively low price point, all which make it an attractive candidate for structural lightweighting of vehicles. The raw materials were manufactured into composite laminates using a compression molding process and then the mechanical properties were characterized using experimental test methods. Properties like stiffness, strength, and strain-to-failure of the composite were characterized using standard ASTM methods, and the resulting properties were directly fed into a computational material model
Patton, Evan G.Hart, Robert J.
ABSTRACT The Dynamic Mode Decomposition (DMD) has shown the ability to extract coherent structures and dominant modes from high dimensional, sequential flow field datasets by decomposing it into spatial patterns and associated time dynamics. This low-rank dataset can then be applied to a linear regression model to predict the future state of the flow. Additionally, the DMD with control (DMDc) algorithm enables the input of control signals to the system, a very promising avenue for developing active aero devices for ground and aerial vehicles. However, existing literature primarily consists of its applications to low Reynolds number flows past simple, and mostly two-dimensional geometries. Given that most flows of engineering interest involve three-dimensional turbulent flows having high Reynolds number, this paper explores and presents DMD analyses of the flow around an idealized ground vehicle (Ahmed body) at a Reynolds number of 2.7 million. The high dimensional dataset for this
Misar, AditNichols, SpencerKorivi, Vamshi M.Tison, Nathan A.Uddin, Mesbah
ABSTRACT Autonomous systems are the future of the Army and Ground Vehicle Systems Center has aligned itself accordingly to support unmanned ground vehicle (UGV) development. Physically testing autonomous algorithms and vehicle systems can be expensive and time consuming, a problem addressed by the use of modeling and simulation (M&S) tools. A multitude of both Government owned and Commercial Off-the-Shelf Tools (COTS) are widely available, all claim to virtually evaluate autonomous ground vehicles operating on various environments and scenarios. Most of the COTS tools primarily focus on the commercial automotive industry where vehicles are driven in a structured environment. In this paper two M&S tools, viz., Autonomous Navigation Virtual Environment Laboratory (ANVEL) and Rover Analysis Modeling and Simulation (ROAMS) are evaluated for military applications, where the demands for navigation include both on-road and off-road, as well as both structured and unstructured environments as
Cole, MichaelLucas, CesarKulkarni, Kumar BCarruth, DanielHudson, ChristopherJayakumar, Paramsothy
ABSTRACT Optical distortion measurements for transparent armor (TA) solutions are critical to ensure occupants can see what is happening outside a vehicle. Unfortunately, optically transparent materials often have poorer mechanical properties than their opaque counterparts which usually results in much thicker layups to provide the same level of protection. Current standards still call for the use of a double exposure method to manually compare the distortion of grid lines. This report presents provides a similar method of analysis with less user input using items typically available in many mechanics labs: machine vision cameras and digital image correlation software. Citation: J. M. Gorman, “An Easier Approach to Measuring Optical Distortion in Transparent Armor”, In Proceedings of the Ground Vehicle Systems Engineering and Technology Symposium (GVSETS), NDIA, Novi, MI, Aug. 11-13, 2020. The views presented are those of the author and do not necessarily represent the views of DoD or
Gorman, James M.
WHY DO WE NEED SIMULATIONS? This paper is intended to provide a broad presentation of the simulation techniques focusing on transmission testing touching a bit on power train testing. Often, we do not have the engine or vehicle to run live proving ground tests on the transmission. By simulating the vehicle and engine, we reduce the overall development time of a new transmission design. For HEV transmissions, the battery may not be available. However, the customer may want to run durability tests on the HEV motor and/or the electronic control module for the HEV motor. What-if scenarios that were created using software simulators can be verified on the test stand using the real transmission. NVH applications may prefer to use an electric motor for engine simulation to reduce the engine noise level in the test cell so transmission noise is more easily discernable
Johnson, Bryce
Small scale testing has proved very useful in exploring the details of buried charge target loading mechanisms. If the target is of reasonable size relative to the charge, the target is loaded in two steps or phases. It has been possible to gain insight into the density distribution in the soil cap that provides the first phase of the target loading. This is expected to be quite useful in validating computational models of the loading. The actual load on a target by the explosion of a buried charge has a significant non-deterministic element. Small scale testing enables one to run enough nominally identical tests to develop sound estimates of the nondeterministic part of the target loading. It appears that both the mean and the standard deviation of this loading are scalable to other charge sizes
Taylor, Leslie C.Fourney, William E.Leiste, H. Ulrich
ABSTRACT The recent U.S. Army TARDEC’s 30-Year Strategy calls for enhancing their skill set in the “ilities,” especially reliability, since this factor directly impacts more than 58% of life cycle costs, according to a DoD study. To support this initiative, this paper presents technology transfer of Iowa developed Reliability-Based Design Optimization (I-RBDO) software by integrating theories and numerical methods that have been developed over a number of years in collaboration with the Automotive Research Center (ARC), which is funded by the U.S. Army TARDEC. Both the sensitivity-based and sampling-based methods for reliability analysis and design optimization methods are integrated in I-RBDO for broader multidisciplinary applications. I-RBDO has very comprehensive capabilities that include modeling of input distributions for both independent and correlated variables; a variable screening method for high dimensional RBDO problems; statistical analysis; reliability analysis; RBDO; and
Choi, K.K.Gaul, Nicholas J.Song, HyeongjinCho, HyunkyooLamb, DavidGorsich, David
ABSTRACT This paper presents the results of a series of controlled tests conducted with large explosive charges in which a number of threat parameters were systematically varied. After each test, careful measurements were made of the crater dimensions. A statistical analysis was conducted in order to relate the measured crater dimensions to the threat characteristics. The test plan examined the effects of charge size, soil type, shape of the charge, and burial depth. The results of the analysis showed that all of the threat parameters had a significant effect on the most commonly measured dimension, the crater lip diameter. As a consequence, any model that attempts to estimate charge size based solely on crater size measurements will necessarily have large predictive errors, on the order of a factor of two or more
Zeleznik, TomMiiller, MattEridon, JamesWest, Jonathan
ABSTRACT The first part of this paper will outline the conception of the testing apparatus (Figure 1), along with its operation and preliminary results. The second part of the paper will discuss a new methodology used to correlate the dependence of crack growth rate for strain crystallizing natural rubbers in terms of tearing energy. The tearing energy which depends on the type of elastomer, geometry and stress strain behavior of a particular specimen demonstrates a direct correlation with the crack growth rate at different R-ratios (= min tearing energy/max tearing energy). Figure 1 Schematic of the testing apparatus
Kujawski, DanielDiStefano, DarenBradford, William
ABSTRACT This paper describes novel experimental methods aimed at understanding the fundamental phenomena governing the motion of lightweight vehicles on dry, granular soils. A single-wheel test rig is used to empirically investigate wheel motion under controlled wheel slip and loading conditions on sandy, dry soil. Test conditions can be designed to replicate typical field scenarios for lightweight robots, while key operational parameters such as drawbar force, torque, and sinkage are measured. This test rig enables imposition of velocities, or application of loads, to interchangeable running gears within a confined soil bin of dimensions 1.5 m long, 0.7 m wide, and 0.4 m deep. This allows testing of small-scale wheels, tracks, and cone or plate penetrators. Aside from standard wheel experiments (i.e., measurements of drawbar force, applied torque, and sinkage during controlled slip runs) two additional experimental methodologies have been developed. The first relies on high-speed
Senatore, CarmineMacLennan, JamieJayakumar, ParamsothyWulfmeier, MarkusIagnemma, Karl
ABSTRACT This paper presents a quantitative analysis and comparison of fuel economy and performance of a series hybrid electric HMMWV (High Mobility Multi-purpose Wheeled Vehicle) military vehicle with a conventional HMMWV of equivalent size. Hybrid vehicle powertrains show improved fuel economy gains due to optimized engine operation and regenerative braking. In this paper, a methodology is presented by which the fuel economy gains due to optimized engine are isolated from the fuel economy gains due to regenerative braking. Validated vehicle models as well as data collected on test tracks are used in the quantitative analysis. The regenerative braking of the hybrid HMMWV is analyzed in terms of efficiency from the kinetic energy at the wheels to the portion of regenerative power which is retrievable by the battery. The engine operation of both the series hybrid and conventional HMMWV are analyzed using a 2-D bin analysis methodology. Finally, the vehicle model is used to make
Nedungadi, AshokMasrur, AbulKhalil, Gus
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