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This specification covers an aluminum alloy in the form of sheet and plate from 0.008 to 4.000 inches (0.20 to 101.60 mm) in thickness, inclusive (see 8.5).
AMS D Nonferrous Alloys Committee
This test can be used to determine the resistance to scuffing of test specimens such as fiberboards, fabrics, vinyl-coated fabrics, leathers, and similar trim materials.
Textile and Flexible Plastics Committee
G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies
ACBG Rolling Element Bearing Committee
This test method outlines the recommended procedure for performing the no-load rotational starting torque test on airframe rolling bearings. Bearings covered by this test method shall be antifriction ball bearings and spherical roller bearings.
ACBG Rolling Element Bearing Committee
This specification covers a titanium alloy in the form of investment castings (see 8.6).
AMS G Titanium and Refractory Metals Committee
This specification covers corrosion-preventive organic substances dissolved or emulsified in a volatile solvent and supplied in the form of a ready-to-use liquid.
AMS B Finishes Processes and Fluids Committee
This specification covers a copper-nickel-tin alloy in the form of bars and rods up to 3.25 inches (83 mm) in nominal thickness (see 8.7).
AMS D Nonferrous Alloys Committee
J1979 DBCJ1979DBC_2026099/7/2026
The SAE J1979 DBC file contains decoding rules for converting raw J1979 data to 'physical values' (Mph, %, etc.). This file lets you easily decode data from heavy duty vehicles (trucks, buses, tractors, etc.). This DBC file download includes: The SAE J1979 DBC file with Includes 2,400+ Parameter Group Numbers (PGNs) and 16,000+ Suspect Parameter Numbers (SPNs), derived from the J1979-2 released in September 2026. One legal license (1 user, 1 PC) matching the DA license DECODE J1979: Convert J1979 data in wide range of software/API tools REVIEW FIRST: Use our CAN ID converter to check if your PGNs are covered CROWD INPUT: Benefit from free corrections based on large user base SAVE HOURS: Avoid manually constructing the DBC file from scratch Improved Accuracy & Reliability A fully standardized DBC file ensures precise signal decoding, eliminating errors and ensuring reliable data interpretation. Interoperability Seamlessly compatible with many different software stacks, enabling frictionless adoption and significantly expanding market reach. Partnership with Vector Informatik GmbH Works seamlessly with Vector’s free software (CANdb++), used by over 90% of the industry, with free download link provided on SAEI’s J1979DBC file landing page. What is a DBC file? A DBC file is a standardized method for storing the "rules" on how to interpret raw CAN bus data. It contains details on what 'signals' (e.g. RPM, Vehicle Speed, …) are contained within which 'messages' (i.e. CAN IDs). In the J1979 standard, messages are referred to as Parameter Group Numbers (PGN) and signals as Suspect Parameter Numbers (SPN). Further, a DBC file includes names, descriptions, positions, and lengths of the signals - as well as how to offset & scale them.
For the mixing of hydroxy-terminated polybutadiene (HTPB) with silicon dioxide particles, this study adopts the Computational Fluid Dynamics (CFD) method to conduct a visual analysis on the fluid flow field characteristics generated by the umbrella-frame impeller (UF impeller) and umbrella-frame combined impeller (UFC impeller). Comparative studies are carried out from the dimensions of particle concentration distribution, fluid flow trend, vorticity, and path line. The results show that compared with the UF impeller, the UFC impeller, equipped with an upper blade structure, enables its generated flow field to cover the entire stirred tank more effectively, significantly improving the solid-liquid mixing efficiency. In addition, the fluid-structure coupled numerical method is used to analyze the structural deformation characteristics and stress distribution law of the impellers. The research findings can provide a reference for the optimization of dispersion and mixing processes of solid particles in high-viscosity fluids.
Li, RuizhengSun, ZhenxingZhang, YanWu, Qiong
Early diagnosis of osteoporosis is crucial for preventing fractures and improving the quality of life of patients. In clinical practice, the mainstream diagnostic methods, such as dual-energy X-ray absorptiometry (DXA), are limited by high equipment costs and ionizing radiation, resulting in a low coverage rate of large-scale early screening. Only less than one-third of brittle fracture patients have received a DXA assessment. To address this issue, this study proposes an innovative diagnostic method based on ultrasonic guided wave technology. This technology is cost-effective and portable, and it overcomes the limitations of X-ray detection in terms of its unsuitability for large-scale early diagnosis. The Young’s modulus and Poisson’s ratio of water are similar to those of soft tissue, so this method utilizes water coupling to simulate the environment of soft tissue around the bone and combines the transverse isotropy of cortical bone, which is an important characteristic that most existing models ignore, to analyze the propagation of guided waves in anisotropic cortical bone. Through the processing of ultrasonic signals using two-dimensional short-time Fourier transform (2D-STFT), the local thickness of cortical bone can be inverted. By establishing a fluid-coupled orthotropic anisotropic plate model, deriving the dispersion equation, solving the theoretical method for the dispersion curve, using the bovine long plate to construct a water-coupled detection platform, and obtaining experimental data to invert the thickness of the bone plate, the local thickness of the bone plate was obtained, proving that this method can effectively reconstruct the thickness changes of anisotropic and variable cross-section cortical bone under simulated soft tissue conditions, with an average relative error of 13%. This lays the foundation for subsequent in vivo experiments and provides a reliable solution for large-scale early osteoporosis screening.
Nong, KexinLi, Bing
The geometrical and velocity scaling behavior of levitation and dragging forces in Electrodynamic suspension (EDS) systems was studied by both analytical and numerical methods, to provide comparisons between designs for both on-board and ground-mounted magnetic components. Effects of system dimension, levitation gap, magnetic field dependence of critical current density, and vehicle velocity were studied. The lift-to-self-weight ratio of two realistic EDS systems and their geometrical scaling were studied numerically.
Shao, NanZhang, ChangShang, LiangYu, Wenjing
Motivated by the negative Poisson’s ratio tetrahedral-trihedral polyhedron (TMP), this study systematically examines the role of self-locking mechanisms in determining the mechanical response and energy absorption capacity of rigid origami metamaterials. Quasi-static compression tests were conducted on specimens exhibiting three distinct geometries (B19, B22, B23) and four wall thicknesses (0.8–2.0 mm). The results of these tests revealed two unique self-locking behaviors. Type I self-locking originates from inter-wall interlocking, characterized by progressively decreasing inter-wall spacing during compression; Type II self-locking originates from interlocking between creases, characterized by creases contacting each other during compression. The fabrication of the specimens was accomplished through the utilization of FDM-based additive manufacturing, employing PEEK material. The results obtained from this study revealed two distinct locking behaviors: It has been demonstrated that type I locking enables sustained deformation without load reduction. In contrast, type II locking has been shown to result in premature collapse and diminished energy absorption capacity. The B22 configuration has been demonstrated to trigger both locking mechanisms concurrently, thereby significantly enhancing performance metrics. This has been evidenced by improvements in both crush force efficiency (CFE) and specific energy absorption (SEA), whilst also delaying densification. In contrast, structures dominated by a single locking mechanism exhibit premature failure (B19) or inefficient energy absorption (B23). These findings emphasize the pivotal role of synchronized self-locking activation and geometric configuration in enhancing impact resistance and energy dissipation, thereby establishing a foundational theoretical framework for the design of advanced metamaterials in protective engineering.
Wu, BaojiWang, HairuiJiang, Heng
This article studies the fatigue damage problem of vehicles under air drop and off-road conditions. First, a multi-body dynamics model of the entire vehicle is established in ADAMS/View to obtain loads and center-of-gravity acceleration under off-road conditions. Subsequently, a finite element model of the vehicle air drop is created in HyperMesh and LS-DYNA to simulate the landing impact and extract loads on key components. By superimposing and spectrum processing the loads from the two conditions, a vehicle load spectrum is compiled and used as input for fatigue analysis. Based on the Miner linear cumulative damage criterion and the material S–N curve, fatigue life predictions are made for key areas of the frame and suspension. The results indicate that the front cross beam and auxiliary longitudinal beam at the bottom of the frame are the most vulnerable components, with the auxiliary longitudinal beam reaching failure under both conditions, but having a limited impact on the overall vehicle operation. Although the peak acceleration under air drop conditions is higher, the off-road conditions lead to more severe cumulative damage due to higher impact frequency and duration. This study provides references for vehicle structural optimization and service reliability enhancement.
Lin, QingpengZhang, QiangFu, LeiHuang, JianbingQin, WeiweiSun, Xiaowang
This study proposes a physics-informed graph convolutional reduced-order model, namely Phys-GCN, for high-fidelity and computationally efficient prediction of steady incompressible flow fields. In Phys-GCN, the incompressible Navier–Stokes equations are embedded into the loss function via residual constraints, such that the spatial feature extraction of graph convolutional networks is integrated with the physics-constrained learning strategy of physics-informed neural networks. This mixed design enables the model to capture complex nonlinear flow features while maintaining a clear level of physical interpretability. Benefiting from the node-edge encoding inherent to graph neural networks, Phys-GCN operates directly on unstructured CFD meshes to learn flow features from graph representations constructed using node attributes and adjacency relationships. In doing so, Phys-GCN dispenses with voxelization or SDF preprocessing and fully preserves the local geometric and topological characteristics of the flow domain. The proposed model is systematically evaluated on steady flows past circular and elliptical cylinders, where the predicted velocity and pressure fields are compared against reference CFD solutions in both interpolation and extrapolation scenarios. Results show that, for all physical quantities, the reconstructed steady flow fields achieve mean relative errors below 5%, exhibiting excellent agreement with the CFD benchmark solutions. After offline training, Phys-GCN achieves inference times that are several orders of magnitude faster than conventional CFD solvers, while maintaining comparable predictive accuracy. These findings demonstrate that Phys-GCN provides an accurate and efficient graph-based and physics-informed surrogate for steady flow-field reconstruction on non-uniform, unstructured meshes, thereby laying a solid foundation for future extensions to more complex three-dimensional and compressible flow configurations.
Xie, HaoranZhou, HaoYu, ChanghaoLi, QiangLiu, TianyuPeng, Jiangzhou
Driven by the growing demand for higher efficiency and load-bearing capacity in fields such as new energy vehicles and heavy-duty engineering machinery, planetary gear sets are increasingly operating at elevated rotational speeds, coupled with a corresponding expansion of their revolution radii. This dual trend directly induces a substantial surge in centrifugal acceleration acting on the internal needle roller bearings. Under the cyclic stress inherent to transmission operations, such enhanced acceleration not only accelerates the initiation of spalling faults on the inner bores of planet gears but also exacerbates the propagation and deterioration of these faults throughout the service life. To elucidate the influence mechanism of inner bore spalling on the dynamic response of planetary gear bearings, this study develops a specialized dynamic model. This model explicitly incorporates the compound kinematic effects of simultaneous rotation and revolution, thereby ensuring a high-fidelity reconstruction of actual operating scenarios. The research systematically investigates how different spalling types and dimensional parameters affect the system’s dynamic behavior. Numerical results demonstrate a positive correlation between the severity of the spalling defect and the dynamic response intensity. Specifically, the expansion of defect dimensions under harsh operating regimes markedly exacerbates both the contact impulses at the needle-roller interface and the overall vibration acceleration amplitudes. Notably, the amplitude increment of the needle rollers is far more pronounced than that of other components. These findings enrich the theoretical understanding of fault-induced dynamic responses in planetary gear systems and provide a solid theoretical and model-based foundation for optimizing the fault diagnosis, condition monitoring, and maintenance strategies of the associated needle roller bearings.
Zou, DeshengLai, JunbinGuo, WeiDong, PengXu, XiangyangSun, Qiang
With the rapid development of the aerospace industry, FEM has been widely applied as a key tool. However, the high complexity of aircraft and spacecraft geometries and structures often leads to unavoidable distorted meshes in FEM, which significantly degrades the accuracy of analysis results. Both the splitting factor and the mesh distortion significantly affect the accuracy of the generalised mixed elements. The coefficient matrix deviation between the distorted element and the standard element was quantified. Thus, the computing equation for a three-dimensional (3D) hexahedral distorted element’s splitting factor was constructed. Examples were used to validate the proposed method. For distorted meshes, the accuracy of NCGME has been improved.
Shen, AoQing, Guanghui
To address the measurement challenges posed by the large diameters and wide spans of engine crankshaft holes, cylinder holes, and camshaft holes, as well as the abnormal laser measurement data caused by oil film adhesion and local protrusion structures on their inner walls, this paper proposes a non-contact coaxiality measurement method based on a laser displacement sensor (LDS) and a threshold-modified least squares ellipse fitting (TMLSE) algorithm. The method first preprocesses the data through median filtering and then employs an adaptive distance threshold based on maximum inter-class variance to eliminate outliers caused by oil film scattering and protrusions, achieving robust fitting of the cross-sectional centers. Subsequently, the datum axis is established using the least squares midline method, ultimately enabling the evaluation of coaxiality error. In the simulation experiments, a dual-hole model with an inner diameter of 100 mm and a spacing of 700 mm was simulated, where the right hole was translated by 1.5 mm to introduce coaxiality error. Each cross-sectional point cloud included 10% protrusion points (protrusion height of 10 mm) along with random noise and data loss simulating the effects of oil film. To assess the robustness of the method, a systematic analysis was conducted on the influence of laser incidence angles [80°,89°]on measurement accuracy. The results show that across different incidence angles, the maximum deviation between the coaxiality error obtained by the TMLSE method and the theoretical value is only 0.1582 mm, which is significantly better than that of the RANSAC, MZC, and MIC methods. Meanwhile, TMLSE demonstrates stable and efficient computational speed. The simulation verifies that this method offers higher fitting accuracy and robustness under both optical interference and variations in installation angle, making it suitable for the precision measurement of key engine hole systems.
Yin, Jiakuo
The application of steam compressors in heating supply of coal-fired power units demonstrates significant energy-saving benefits, while also effectively addressing the operational constraints of steam supply at low loads, thereby achieving thermoelectric decoupling.. This study analyzes and compares the performance characteristics and operational ranges of three distinct mechanical steam compression technologies. Although centrifugal compressors exhibit a low single-stage pressure ratio, their operational flow rate and temperature ranges are better suited for coal-fired heating requirements. Three typical application scenarios of steam compressors in industrial steam supply for coal-fired power units are proposed: Steam compressors enable waste heat recovery by compressing turbine exhaust steam for heating purposes, increase pressure in branch networks of steam supply pipelines to achieve high-pressure steam delivery, and enhance industrial steam extraction pressure under low-load conditions to realize thermoelectric decoupling. This enables substantial improvement in both the energy efficiency and steam supply capacity of coal-fired power units. Based on practical application cases of steam compressor systems, the objectives of steam pressure and temperature elevation can be achieved. Through collaborative adjustment of the drive motor frequency and the recirculation valve, dual-objective control of outlet flow rate and temperature can be realized. An analytical model was developed to simulate compressor performance, and validation against actual operational data confirmed the model’s applicability for guiding operational practices and control simulations. The centrifugal steam compressor in actual operation demonstrates normal performance across all operational indicators under high-speed conditions, confirming its technical reliability in coal-fired heating applications and providing crucial references for the widespread adoption of steam compressor technology in steam supply systems of coal power units. It expands the steam supply parameter range of electro-thermal conversion systems, thereby making a positive contribution to renewable energy integration.
Zhang, PanLiu, Yan
The radio altimeter is an important navigation instrument on an aircraft, capable of accurately measuring the aircraft's true height above the ground or sea to ensure safe flight. This capability is crucial for ensuring normal flight operations, especially during critical phases such as takeoff, approach, and landing. Polar terrain is complex and continually changing. The vast, endless ice fields, crisscrossing glacier crevasses, towering icebergs, and weather conditions all add significant uncertainty to air travel. In such environments, the aircraft's navigation system is particularly important as a core device to ensure flight safety. This article provides a brief overview of the aircraft radio altimeter system. Using data and observations from production flight tests, it studies the specific challenges posed by radio altimeter failures encountered during these critical validation flights. The study synthesizes these findings and proposes a relatively general troubleshooting approach to address such issues. Furthermore, the effectiveness of this method has been rigorously validated through its application in solving a complex real-world radar altimeter failure case.
Song, MingmingMi, Yujie
The determination of flight thrust for aircraft engines is an important means of evaluating engine and aircraft performance. The characteristics of the tail nozzle of the tested engine are an important data support for calculating flight thrust. In order to accurately evaluate the flight thrust of a certain type of engine, an “engine nozzle characteristic determination test system” is developed to obtain the thrust characteristic curve and flow characteristic curve of the nozzle. A calibration device and calibration process were designed for the experimental system to achieve in-situ calibration of the system.
Ren, BoyangJia, WenjieSong, Jiangtao
Unsteady vibrations of vehicles, which can be easily perceived by the human body, may affect the driving experience and compromise driving comfort. However, the conventional three-point powertrain mounting system (PMS) often fails to offer a satisfactory solution. Here, a novel four-point PMS was proposed by introducing a semi-active strut (SAS), which can provide stronger damping in a low-frequency range to resolve this problem. Specifically, a thirteen degrees of freedom (DoFs) vehicle dynamic model (VDM) with four mounts was constructed, and the evaluation indices for unsteady vibration responses of the vehicle were determined and analyzed; Next, the PMS optimization design approach was employed to identify the proper position of installation and dynamic stiffness of the SAS, and meanwhile the 13 DoFs VDM and the force-sharing principle were used to identify the structural parameters of the strut; Last, comparative experiments were performed to analyze the effect of the strut on alleviating the unsteady vibration of the vehicle under varied unsteady vehicle states. The results showed that the SAS has significantly reduced the seat rail peak acceleration, verifying the effectiveness of our novel PMS in alleviating the unsteady vibration. The research provided a feasible solution to alleviate the unsteady vibration of vehicles and improve the driving experience.
Wang, DaoyongLiu, YongjiangMa, Bo