Engineer Research and Development Center News Releases

Surface Oxide Removal in Preparation for Controlled Liquid Metal Embrittlement

Press Operations — Thu, 07 May 2026 17:05:00 GMT

Abstract: During liquid metal embrittlement a liquid metal inﬁltrates grain boundaries of a compatible solid metal, interrupting the inter-grain bonds and weakening the metal. Ongoing research has proposed that this effect may be used to perform additive/subtractive hybrid machining to fabricate replacement components, using relatively simple equipment and low material and instrument costs. The gallium/aluminum pairing is of particular interest due to the usage of aluminum in a wide variety of structural and aerospace applications coupled with gallium’s nontoxicity and melting point just above room temperature, which facilitates storage and transport. To activate aluminum to gallium inﬁltration, the surface oxide formed on aluminum in atmosphere must ﬁrst be removed simultaneously with a signiﬁcant amount of bulk metal to promote ﬂow control of the liquid metal. Three targeted techniques for oxide removal were tested and compared, speciﬁcally mechanical abrasion, chemical etching, and laser ablation. Mechanical abrasion is simple to implement but lower precision. Chemical etching requires signiﬁcant prep work and cleanup but could operate on entire sheets of substrate simultaneously with proper masking. Although laser ablation requires the most complex instrumentation, it requires minimal prep work and provides the greatest precision, making it ideal for the manufacturing application under development here.

Tribological Properties of Synthetic and Biosourced Lubricants Enhanced by Graphene and Its Derivatives: A Review

Press Operations — Thu, 07 May 2026 16:57:00 GMT

Abstract: This review explores the tribological properties of biosourced lubricants (biolubricants) enhanced by graphene (Gr) and its derivatives and hybrids. Friction and wear at mechanical interfaces are the primary causes of energy loss and machinery degradation, necessitating effective lubrication strategies. Traditional lubricants derived from mineral oils present environmental challenges, leading to an increased interest in biolubricants derived from plant oils and animal fats. Biolubricants offer high biodegradability, renewability, and low toxicity, positioning them as ecofriendly alternatives. This work extensively reviews the role of Gr-based nanoadditives in enhancing the lubrication properties of biolubricants. Gr with its exceptional physicomechanical properties has shown promise in reducing friction and wear. The review covers various Gr derivatives, including Gr oxide (GO) and reduced Gr oxide (r-GO), and their performance as lubrication additives. The discussion extends to Gr hybrids with metals, polymers, and other 2D materials, highlighting their synergistic effects on the tribological performance. The mechanisms through which these additives enhance lubrication, such as the formation of protective films and improved interactions between lubricants and tribopairs, are examined. Emphasis is placed on the environmental benefits and potential performance improvements of Gr-based biolubricants. Finally, by analyzing current research and technological trends, the paper outlines future prospects for optimizing lubricant formulations with Gr-based nanoadditives, aiming for more sustainable and efficient tribological applications.

Insight into the Photocatalytic Degradation Mechanism for “Forever Chemicals” PFNA by Reduced Graphene Oxide/WO3 Nanoflower Heterostructures

Press Operations — Mon, 04 May 2026 19:49:00 GMT

Abstract: Water contamination with “forever chemicals” like per- and polyfluoroalkyl substances (PFAS) poses significant toxicity to the environment. Since they are the most persistent synthetic chemicals that hardly degrade in the natural environment and are carcinogenic to humans, there is an urgent need to discover novel processes for destroying PFAS. Herein, we report on the design of a reduced graphene oxide (r-GO)/WO3 nanoflower (WO3-NF)-based heterostructure for harnessing 365 nm light-driven photocatalytic oxidation and reduction process toward the photocatalytic degradation of perfluorononanoic acid (PFNA). Moreover, reported data reveal that using an r-GO/WO3-NF heterostructure photocatalyst, 100% PFNA degradation and 14% defluorination can be achieved in the presence of isopropyl alcohol as the hydroxy radical (•OH) quencher or glucose as a hot hole (h+) quencher after exposure to 365 nm light for 22 h. A reported mechanistic study shows synergistic oxidation and reduction processes are vital for the complete degradation of PFNA, where the hydrated electron (eaq−) plays a key role as a reducing agent and h+ and •OH act as oxidation agents. Furthermore, the photocatalytic destruction mechanism study indicates that chain shortening via C−C bond breaking and defluorination via C−F bond breaking are major pathways for PFNA degradation. A wavelength-dependent study shows that only 22% degradation can be achieved after exposure to 532 nm light for 22 h, which is due to the lack of the formation of hydrated electrons (eaq−). The current study sheds light on the construction of the r-GO/WO3 NF heterojunction for the highly efficient degradation of PFAS.

Erosion Test Database Reassessment with Application to Engineered Soils

Press Operations — Mon, 04 May 2026 19:36:00 GMT

Abstract: This report presents a reevaluation of the soil erosion property relation-ships and a reanalysis of the data with a specific focus on compacted and engineered fill materials. Reinterpretation first centered on describing the parametric space of the database in which the models’ ability to predict critical shear stress and the erodibility coefficient parameter have the greatest uncertainty. Second, this work considered the smaller subset of the dataset with only engineered fill and compacted materials. However, considering only this subset was not found to reduce significantly the uncertainty in predictive capability. We recommend additional work to expand the dataset, focusing on materials in conditions more representative of the compacted and aged soils present on many flood control infrastructure projects.

An Investigation of Causes of Inaccuracy of Infrared Radiation Cameras for Large-Scale Additive Manufacturing Applications

Press Operations — Mon, 04 May 2026 19:33:00 GMT

Abstract: In additive manufacturing, accurate temperature data are needed for both real-time feedback for print operators and understanding the thermomechanical behavior for prediction and part quality characterization. Through the collection of accurate temperature data, thermal models can be validated to predict process-induced properties of parts. Infrared radiation (IR) is used to determine the temperature of a surface. Because IR cameras measure thermal radiation from a distance without contact, they are safe to use in high-temperature environments like 3D printing. An investigation of reported temperature values for multiple cameras during one print showed a decreasing trend for cameras close to the printer’s heat sources, which was not reflective of the printing process, and a discrepancy of ±20°C when printing at 200°C across overlapping camera views. Two more prints were studied to determine whether this camera behavior was unique to that print and geometry. The analysis showed the same results across all three prints, with camera-reported values having inconsistencies for a single layer, a subset of layers, and the scale of the print. Multiple possibilities for the cameras’ variances were explored. The IR cameras were determined to require further calibration and experimentation before reported temperature values can be treated as physical temperature values.

Bridge Load Rating for US Army Installations: Guidance

Press Operations — Wed, 29 Apr 2026 20:41:00 GMT

Abstract: This report summarizes Army policy and provides technical guidance for the load rating of vehicular and railroad bridges on US Army installations. These bridges must be load rated to determine and ensure their abilities to support the Army’s heavy military vehicles as well as all public-sector cars, trucks, or trains (in the case of railroad bridges). Installation bridge management and load ratings are accomplished under the Installation Management Command (IMCOM) Army Dams and Transportation Infrastructure Program (ADTIP), with technical support from the US Army Engineer Research and Development Center (ERDC).

Deep Learning Approaches for Buried Object Detection in Infrared Imagery

Press Operations — Wed, 29 Apr 2026 20:34:00 GMT

Abstract: Artificial intelligence and machine learning techniques are increasingly utilized to detect buried objects in thermal infrared imagery. This task relies heavily on the quality and diversity of the training dataset, requiring datasets that capture variability present in real-world environments. Synthetic imagery offers a means to expose algorithms to a greater range of conditions than is often available in real-world data alone. This study evaluates the performance of three open-source object detection models—Faster Region-Based Convolutional Neural Network (R-CNN), You Only Look Once (YOLOv8), and Single Shot Multibox Detector—trained using real-world, synthetic, and hybrid datasets. Real-world imagery was collected from a single field site, while synthetic data were generated using the Virtual Environmental Simulation for Physics-Based Analysis software suite. Model performance was evaluated using Intersection over Union and confidence scores. Models trained exclusively on synthetic datasets with limited scene diversity, when tested on real-world imagery from the same location, produce high false-positive and false-negative rates. Detection performance im-proved significantly for Faster R-CNN and YOLOv8 when trained using a hybrid dataset combining real-world and synthetic data. Analysis of red-green-blue histograms revealed differences in pixel intensity distributions between real and synthetic imagery, indicating areas for improving synthetic data generation.

Forward Operating Remote Camera for Engineering—Construction Assurance and Monitoring (FORCE-CAM), Generation 1

Press Operations — Wed, 29 Apr 2026 20:31:00 GMT

Abstract: This research delivered a first-generation, real-time construction monitoring capability, enabling visual situational awareness for off-site subject matter experts. The live-streamed and recorded data can be visualized from a remote computer desktop to aid in identifying non-conformance issues during active paving operations or during concrete damage assessment and repair operations. Experimentation on asphalt paving and skid-steer construction equipment using direct electro-optical and thermal sensors provided validation of the efficacy of this solution.

Statistical Analysis of Large Format Additively Manufactured Polyethylene Terephthalate Glycol with 30% Carbon Fiber Tensile Data

Press Operations — Wed, 22 Apr 2026 20:31:00 GMT

Abstract: In large format additive manufacturing (LFAM), a keener understanding of the relationship between the manufacture method and material temperature dependency is needed for the production of large polymer parts. Statistical analyses supported by material properties and a meso-structural understanding of LFAM are applied to elucidate tensile data trends. The data from LFAM polyethylene terephthalate glycol with 30% carbon fiber (CF) (PETG CF30%) panels (diagonal, horizontal, and vertical in the x-y print plane) and injection-molded specimens tensile tested at six different testing temperatures (room temperature, 40 ◦C, 50 ◦C, 60 ◦C, 70 ◦C, and 80 ◦C) were used for statistical analyses. A standard deviation, a coefficient of variation, and a two-way and one-way analyses of variance (ANOVA) were conducted. The manufacturing method (44.2%) and temperature (47.4%) have a strong effect on the ultimate tensile strength, in which temperature (82.6%) dominates Young’s modulus. To explain the difference between the ultimate tensile strength of vertical, diagonal, and horizontal specimens at room temperature, a visual inspection of the specimen failure was conducted and the maximum stress at the crack tip was calculated analytically. The decreased strength in the diagonal specimens resulted from the reliance on interlaminar adhesion strength. Future work will consider the effect of the void space variation on tensile strength variance.

Mesoscale Modeling and Parametric Studies of Concrete Materials

Press Operations — Wed, 22 Apr 2026 17:35:00 GMT

Abstract: This research focused on creating a mesoscale finite element model of concrete, treating it as a three-phase composite material composed of coarse aggregates, mortar, and the Interfacial Transition Zone (ITZ). The objective was to understand how these mesoscale structures influence the material's properties and responses under various loading conditions. The model simulated a normal-strength concrete with a compressive strength of approximately 27 MPa. The simulations included unconfined uniaxial compression, hydrostatic compression, uniaxial strain compression and triaxial compression, with the model's dimensions and boundary conditions mirroring those of laboratory tests on cylindrical specimens. The results from the simulations corresponded well with experimental data, validating the accuracy of the modeling method. Further parametric studies were conducted to examine how attributes like aggregate volume fraction and material properties impact the concrete's overall performance. This validated modeling provides a reliable pathway for optimizing concrete materials for specific uses, such as designing hardened structures for military applications. It also offers a method for estimating concrete properties when laboratory testing is limited or unavailable.

Laboratory Performance Evaluation of Coarse Aggregates for Asphalt Concrete Mixtures

Press Operations — Wed, 22 Apr 2026 17:31:00 GMT

Abstract: An extensive laboratory evaluation was conducted to investigate the performance of coarse aggregates under different test methods. Test methods including the Los Angeles abrasion (LAA), sulfate soundness, Micro-Deval abrasion, aggregate crushing value, aggregate impact value, aggregate durability index, and aggregate slake durability were chosen to determine the aggregates’ resistance to abrasion, impact, crushing, and soundness. A total of twenty-five aggregate sources were included in the laboratory experiments, including seven different aggregate types (crushed gravel, gabbro, greywacke, granite, limestone, monzonite, and sandstone). The mineral composition of the aggregate sources was determined using X-ray diffraction (XRD) analyses. According to this study, the LAA test results were reasonable in screening out an aggregate source perceived as marginally resistant to abrasion. The sulfate soundness test results were ineffective in quantifying the quality of the different aggregate sources. Most alternative test methods identified similarly unacceptable aggregate sources, consisting mainly of aggregate types composed of carbonate minerals. Strong statistical correlations were not found among the aggregate test parameters. Recommendations were given to further investigate existing test requirements for the selection of coarse aggregates, particularly when using the sulfate soundness test method.

Validation of the Swift and Quiet Airfield Assessment Device (SQUAAD)

Press Operations — Wed, 22 Apr 2026 17:26:00 GMT

Abstract: The need to rapidly determine the subsurface strength required to support various aircraft loading during contingency operations is critical to the success of tactical missions. Current Air Force Special Operations teams are required to perform this task using the dynamic cone penetrometer (DCP), a destructive test method that requires up to three personnel to operate, is time-consuming and representative of only a small area, requiring multiple tests to evaluate terrain suitable for airfield landing. An alternative, nondestructive methodology to capture the subsurface strength is the Swift and Quiet Airfield Assessment Device (SQUAAD). The purpose of the study presented in this report was to validate the SQUAAD to provide military personnel confidence in the operation and accuracy of the unit with respect to the legacy DCP device. A series of nine full-scale test sections were constructed at the US Army Engineer Research and Development Center’s indoor pavement testing facility. The test results indicate that the SQUAAD requires further testing and evaluation before it can replace the DCP.

Transient Seepage Analysis for Flood Control Embankments

Press Operations — Wed, 22 Apr 2026 17:23:00 GMT

Abstract: Transient seepage analyses, which are becoming more common in practice, carry inherently more complexity compared with traditional saturated steady-state seepage analyses. The results of a four-year remote monitoring investigation were used to investigate common practices used in transient seepage analyses. Initial pore water pressure distributions were found to correspond to predicted infiltration distributions, which were less than typically assumed. The laboratory-measured drying soil water retention curve was found to provide an upper bound to field measurements. Field-measured soil water retention data were found to better correspond to a mean between the laboratory wetting and drying curves. Transient seepage and stability analyses showed that using a drying soil water retention curve resulted in lower factors of safety compared with using a wetting curve. However, a mean curve between the wetting and drying curves proved to be more accurate when compared with representative field measurements. Using unsaturated shear strengths along with conventional saturated shear strengths for levee embankments was found to minimally contribute to the stability factor of safety. Incorporating the findings from this investigation into a transient seepage analysis will help to improve the reliability of the results.

Restoring the Flexible Pavement Test Track to Monitor Impact of Military Ground Vehicles

Press Operations — Fri, 17 Apr 2026 14:16:00 GMT

Abstract: Full-scale tests for pavement design, construction, evaluation, and maintenance benefit from designated facilities where pavement elements can be controlled and monitored. A loop test track at the US Army Engineer Research and Development Center (ERDC) Vicksburg campus was constructed between September 1986 and September 1988. This report describes activities to restore that pavement test track through reconstruction. ERDC constructed a road structure consisting of 4 in. of asphalt concrete over 6 in. of aggregate base course over native subgrade material on the site of the original test track. The pavement structure was instrumented with earth pressure cells and moisture probes at the subgrade, or base, course interface. Material testing and as-constructed properties are documented herein to allow future traffic studies that use the constructed test track to create numerical simulations and calibrate their embedded models with real-world data. This report details construction activities and material properties for future reference.

Verification and Validation of Modeling of Fluid–Solid Interaction in Explosion-Resistant Designs Using Material Point Method

Press Operations — Tue, 14 Apr 2026 12:52:00 GMT

Abstract: Verifying and validating explosion-resistant design models are challenging tasks due to the difficulties in accurately capturing the failure evolution within a setup influenced by the combined effects of fluid–solid interactions, blast waves, fragmentation, and impact. Curtain wall system, as a key structural component, is widely used in various types of buildings for its aesthetic appeal and weather protection. Hence, optimizing the explosion-resistance of such systems is necessary to improve building safety. In this work, we develop computational procedures that can be used to enhance the design of blast-resistant structures. This paper focuses on studying a representative component from a typical curtain wall system, as well as a small-scale modeling of shock tube testing. For that, the material point method simulations are verified against the finite element method simulations, and the computational results are validated against shock tube testing. The work objective is to evaluate the simulation fidelity of explosion responses in several case studies. The first case study demonstrates how the MPM captures damage and fragmentation in a typical confined explosion event involving FSI, thus, providing an improved physical description compared to the FEM. The second case study qualitatively compares the MPM’s ability to simulate the shock tube response with experimental observations. Since the second study validates that the MPM solution is qualitatively consistent with the experimental data, the MPM model is then used in the third case study to establish an FEM model that could capture the same physics. This FEM model can be scaled up to model field experiments. The fourth case study involves the development of an FEM model for a representative curtain wall system component, which is validated against experimental results and then scaled down and employed to validate a corresponding MPM model. The proposed procedure provides a feasible approach to verifying and validating explosion-resistant designs for more general cases.

Silica Particulate Dispersion During Additive Friction Deposition in a Metal Matrix Composite

Press Operations — Mon, 13 Apr 2026 12:47:00 GMT

Abstract: This work presents a study of a low-power, solid-state additive manufacturing process to simultaneously mix and build a metal matrix composite. Speciﬁcally, an Al 6061 powder was blended with 11 wt% silica (SiO2) after which the powders were solid-state consolidated through additive friction stir deposition (AFSD). The inclusion of the SiO2 resulted in an average hardness of 70 ± 1 HV as compared to a control (no SiO2) of 52 ± 1 Hv. However, for the SiO2 composite, the hardness varied in both the radial build and vertical build directions, with the highest hardness found in the centerline of the deposit. This inhomogeneity has been contributed to differences in how the SiO2 particulates evolve during the stirring and mixing processes of AFSD. Furthermore, this variation in particulate evolution was found to be a useful marker in understanding the microstructure evolution through AFSD.

An Updated Irwin Sensor for Measurement of Surface Shear Velocity

Press Operations — Wed, 18 Mar 2026 20:47:00 GMT

Abstract: Accurate and efﬁcient collection of ﬁeld data related to aeolian processes is critical for improving wind erosion predictions and related management decisions. The Irwin sensor has been used in numerous wind tunnel and ﬁeld studies to indicate surface shear velocity. However, the sensitivity of the sensor makes them difﬁcult to maintain in a range of environmental conditions. This study presents a new generation of Irwin sensor incorporating updated electronics, battery operation, wireless data transmission, and streamlined ﬁeld deployment and removal. A total of 20 sensors were manufactured and calibrated in a wind tunnel at the Engineer Research and Development Center. A subset of the sensors was calibrated using a PI-SWERL, which conﬁrmed the two calibration methods converge on similar values for ﬂat smooth test surfaces. The updated sensors were installed around a mesquite shrub at the Jornada Experimental Range, New Mexico, USA from February to July 2023. We found that initial data from the sensors accurately captured spatial patterns of surface shear velocity surrounding the shrub. The improvements to the sensor reduced workload for both deployment and maintenance, and reduced disturbance at the ﬁeld site. We discuss potential opportunities to use the improved sensor network in a range of geomorphological research areas including quantifying aeolian sediment transport, building and parameterizing wind erosion models that incorporate spatial dependencies, and improving predictive tools for landform change.

Modeling the Service Life of Temporary Airfield Operational Surfaces Under Multi-Pass Aircraft Trafficking

Press Operations — Wed, 18 Feb 2026 21:46:00 GMT

Abstract: Expeditionary Airﬁeld (EAF) surfacing systems are designed to create temporary aircraft operating surfaces. Modeling the service life of EAF surfacing systems including the matting system, aircraft, and subgrade, has historically proven difﬁcult, exacerbated by variability between systems and the multitude of mechanisms that can constitute failure. The study presented herein outlines the development and implementation of a performance modeling approach that includes a multi-scale scheme that accounts for local characteristics of the connection points of the EAF matting system, coupled to the global characteristics of the matting array to predict cyclic passes to failure. Finite element studies were conducted for an EAF surfacing system brickwork conﬁguration subjected to aircraft strut loads over varying California Bearing Ratio (CBR) subgrades to calibrate a transfer function to full-scale trafﬁcking experiments. The proposed framework is then used to predict the rate of subgrade deformation for additional lay patterns, which successfully ranked the performance of each relative to full-scale trafﬁcking experiments. An approach is proposed to couple the rate of subgrade deformation with local ﬁnite element models to capture increasing joint damage as permanent deformation accumulates, and supplemented by a variable amplitude cycle counting and damage accumulation algorithm that yields reasonable agreement with full-scale experiments while capturing the transition in failure mechanisms at higher CBR values. The results of the study presented herein captures the propensity for end connector and subgrade failure over a range of subgrade CBRs and shows promise for a broader performance framework that can be extended to other EAF surfacing systems, aircraft types, and speciﬁc matting lay patterns.

Morphology-Driven Electromagnetic Shielding Performance of Graphitic Nanoparticles in Segregated Polypropylene Nanocomposites via Electromagnetic Melt Processing

Press Operations — Fri, 13 Feb 2026 21:29:00 GMT

Abstract: Electromagnetic melt-processing has emerged as an innovative and energy-efﬁcient strategy for the structuring of thermoplastic nanocomposites. In this study, polypropylene (PP)-based TPNCs were fabricated using different grades of graphitic carbon nanoparticles to yield electrical conductivity and electromagnetic interference shielding effectiveness. The applied structuring methodology consists of a multiscale processing strategy that combines high-energy ball milling of polymer micro-pellets and CNPs, formulated powder compaction into green bodies, and EM-driven localized heating to produce the TPNCs. This enables the formation of highly segregated, percolated conductive networks at ultra-low ﬁller loadings. The percolation threshold values for green bodies were signiﬁcantly dependent on CNP morphology, ranging from approximately 0.50 wt% for low-aspect-ratio graphene nanoplatelets to around 1.0 wt% for medium-aspect-ratio carbon nanotubes. Upon EM melt-processing, due to viscoelastic deformation of CNP networks, the resulting threshold values of the structured TPNCs were approximately 0.73 wt%, 0.50 wt%, and 0.74 wt% for low, medium, and high aspect ratios, respectively. High-aspect-ratio CNTs, despite exhibiting greater structural defects, achieved the highest EMI SE of 19.7 dB/mm at 10 wt%, demonstrating that morphology dominates over graphitic crystallinity in governing transport properties and electromagnetic performance. Statistical modeling via response surface methodology conﬁrmed the predictive signiﬁcance of the CNP morphology and the concentration responses. This work underscores the critical inﬂuence of ﬁller architecture and EM-induced structuring in enabling a novel, scalable platform for multifunctional polymer nanocomposites with enhanced electromagnetic shielding capabilities, offering promise for next-generation aerospace, electronics, automotive, and defense applications.

Mechanical Properties and Microstructure of Annealed Ni/CrC-NiCr Metal Matrix Composite Prepared by Cold Sprayed Deposition

Press Operations — Thu, 12 Feb 2026 17:37:00 GMT

Abstract: This study investigates the effects of low (700 ◦C) and high (1000 ◦C) temperature annealing on the micro-structure and mechanical properties of two metal matrix composites consisting of Ni and two separate compositions of CrC-NiCr cold-sprayed onto A-514 structure steel. The mechanical properties, including tensile strength, ductility, interface shear strength, and microhardness, were evaluated after heat treatments. Additionally, scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), and transmission electron microscopy (TEM) were used to characterize the microstructure of the annealed deposits. The results showed that annealing signiﬁcantly enhanced the inter-splat bonding quality between the matrix (nickel) particles. However, higher temperature annealing led to an increase in voids surrounding the cermet particle due to enhanced elemental diffusion. Furthermore, the interparticle bonding between the nickel particles in the matrix and the cermet particle was also improved after annealing. Depending on the composition, the ultimate tensile strength increased by a minimum of 32 %, and the adhesion shear strength improved by over 77 % following annealing at 1000 ◦C. Recrystallization and reduction of the dislocation density in the nickel matrix occurred within the splats during annealing, resulting in increased ductility from less than 0.2 % in the as sprayed condition to more than 6.5 % after annealing. However, a general reduction in hardness was observed after annealing. The interplay between the annealing temperature, microstructural evolution, and mechanical performance demonstrates that the improved bonding directly inﬂuenced the mechanical properties, resulting in increased tensile strength, greater ductility, and a shift from brittle to ductile fracture behavior as the micro-structure evolved.