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This specification covers a corrosion- and heat-resistant steel in the form of wire.
AMS F Corrosion and Heat Resistant Alloys Committee
S-cam brake is a drum-type foundation brake used in heavy commercial vehicles. It is a safety-critical device; hence, thorough validation of its performance by lab test rigs and field tests is essential. During prototype testing, an unusual impact was observed during dynamic braking at high pressure application, specifically when the brake drum is rotating, after a period of operation of about 10,000 cycles. This phenomenon was then observed even at static braking when the brake drum was at rest. From initial inspection, it is due to the cam roller, which rides on the web-slot provided at the shoe assembly, while the S-cam is rotating and falls back instantly. This phenomenon occurs repeatedly and creates an audible noise, which needs to be eliminated. The study aims to correlate the phenomenon using finite element analysis (FEA) as in a prototype test and to identify the root cause and optimize the design variables. Since the friction coefficient at the cam roller–web interface is unknown after a period of operation, different values of friction coefficient, ranging from 0.1 to 0.8, are iterated and simulated by rotating the S-cam until the braking effort is reached. The dynamic implicit analysis procedure in Abaqus standard is used to simulate this condition. Based on the results, design variables were improved to mitigate the issue. A quick solution, achieved by modifying a minor feature, successfully prevented the fallback behavior and was validated through physical testing. Furthermore, a permanent solution was developed to eliminate both the “ride-on” and “fallback” phenomena by optimizing component dimensions. This FEA methodology helps to validate the design in an initial concept phase itself for future variants. Using this method, even the structural and fatigue performance of braking parts can be validated at a system-level simulation with better accuracy.
Dinesh Kumar, J.Riyaz Mohamed, D.Vasanth Bharath, S.Rajkumar, S.Murugan, S.
Nickel-based superalloys are becoming common in the automotive exhaust and turbocharger systems, wherein components are subjected to extreme thermal, mechanical, and oxidative conditions. Nimonic C263 exhibits high-temperature strength and creep resistance. But its surface is susceptible to degradation under service conditions. Electroless composite deposition is a surface engineering technique in which metal ions are chemically reduced and deposited onto the substrate without external electrical energy, enabling uniform and adherent coatings. In this study, electroless nickel-phosphorous (Ni–P)/multiwalled carbon nanotube (MWCNT) composite coating has been deposited on Nimonic C263 substrates. Two carbon nanotube (CNT) concentrations (0.20 g and 0.36 g) were investigated. Scanning electron microscopy (SEM) was used to analyze surface morphology and CNT dispersion, while micro-Vickers hardness testing was conducted in accordance with ASTM E384 using a diamond pyramid indenter at a load of 100 g and a dwell time of 15 s. The Ni–P/0.20 g MWCNT coating exhibited superior hardness due to uniform CNT dispersion and improved microstructural characteristics. Higher CNT concentration results in agglomeration and reduced coating efficiency. The experimental findings would be a quality dataset to optimize composite coating in future with the use of artificial intelligence and machine learning. The paper emphasizes the uniqueness of coating Nimonic C263 superalloy with Ni–P/MWCNT composite coatings, which is not as extensively studied as traditional materials. The best CNT concentration of 0.20 g is found in order to experience the best microstructural uniformity and hardness. The findings provide a definite structure–property relationship between the dispersion of CNT and mechanical performance, which makes the coating to be practical in high-temperature automotive applications.
Vinoth, N.Anush Raj, B.Lokeshkumar, J.Vishnu, N.
This specification covers a corrosion- and heat-resistant nickel alloy in the form of welding wire.
AMS F Corrosion and Heat Resistant Alloys Committee
This specification covers a gold-palladium-nickel alloy in the form of wire, rod, sheet, strip, foil, pig, powder, shot, chips, preforms, and a viscous mixture (paste) of the powder in a suitable binder.
AMS F Corrosion and Heat Resistant Alloys Committee
This specification covers an iron-nickel alloy in the form of strip 0.020 to 0.250 inch (0.51 to 6.35 mm), inclusive, in nominal thickness.
AMS F Corrosion and Heat Resistant Alloys Committee
This specification covers a corrosion- and heat-resistant nickel alloy in the form of welding wire.
AMS F Corrosion and Heat Resistant Alloys Committee
This specification covers a corrosion-resistant steel in the form of bars, wire, forgings, extrusions, flash-welded rings, and stock for forging, extruding, or flash-welded rings.
AMS F Corrosion and Heat Resistant Alloys Committee
This specification covers a corrosion- and heat-resistant nickel alloy in the form of welding wire.
AMS F Corrosion and Heat Resistant Alloys Committee
This specification covers a nitriding grade of premium aircraft-quality, low-alloy steel in the form of bars, forgings, mechanical tubing, and forging stock. AMS6496 and AMS6498 cover UNS K23280 with other quality levels.
AMS E Carbon and Low Alloy Steels Committee
This specification covers a manganese bronze alloy in the form of sand and centrifugal castings (see 8.5).
AMS D Nonferrous Alloys Committee
This specification covers a corrosion- and heat-resistant steel in the form of welding wire.
AMS F Corrosion and Heat Resistant Alloys Committee
This specification covers a corrosion- and heat-resistant steel in the form of welding wire.
AMS F Corrosion and Heat Resistant Alloys Committee
This SAE Aerospace Recommended Practice (ARP) establishes methods for testing airframe plain bearings. The purpose of ARP5448 and its associated slash sheets is to document test methods commonly used to evaluate airframe bearings. These test methods may be referenced in specifications, part standards, purchase orders, etc., when the test is deemed appropriate to the intended use of the bearing by the end user of the bearing. These test methods are not intended to encompass every conceivable requirement for an airframe bearing. The end user of the bearing must exercise engineering judgment to determine the most appropriate standard and/or nonstandard tests for the application.
ACBG Plain Bearing Committee
Aircraft assembly systems, as a critical phase in aerospace manufacturing, face significant challenges in maintaining production efficiency and ensuring product quality. This complex manufacturing system exhibits two distinct characteristics: (1) tightly coupled interactions among manufacturing elements involving process sequences, material flows, and equipment utilization; and (2) dynamic resource allocation and material distribution plans. The inherent variability in production element configurations often leads to operational instability and schedule deviations, which may result in abnormal production states. To address these challenges, this study proposes a data-driven predictive framework that integrates Long Short-Term Memory (LSTM) neural networks with multi-criteria evaluation. The developed LSTM-based model effectively forecasts two critical production indicators of cycle time and balance rate, achieving temporal prediction through historical operational data analysis. The proposed methodology facilitates timely anomaly detection and early warning, allowing proactive risk mitigation and ensuring sustained production system stability. This research contributes to advancing intelligent monitoring and control strategies for aircraft assembly operations within data-driven manufacturing environments.
Chen, BolinWu, JunjieSun, JinfengWang, Kai
In the marine environment, navigation safety and operational effectiveness depend heavily on the precision of liquid level/capacity measurement equipment and systems. In order to examine their measurement accuracy under complex operational situations, including ship navigation states and water tank sloshing, this study employed computational fluid dynamics (CFD) methodologies. The numerical technique performs a thorough examination of how various operating conditions impact measurement accuracy and integrates the volume of fluid (VOF) model and laminar flow model with appropriately defined boundary conditions and solver settings. The findings indicate that constant-speed navigation has minimal impact on accuracy, horizontal acceleration causes moderate deviations, and accelerated diving greatly reduces precision. The amplitude of water tank sloshing has a positive correlation with measurement error. When sloshing amplitudes are less than 1 m, the integration of the resulting acceleration efficiently lowers deviations while preserving excellent accuracy. In light of these results, we advise adding accelerometers to differential pressure transmitters to improve measurement precision. This investigation provides data-driven references and technical solutions for system design and operational standard formulation in marine measurement systems.
Shang, JinQin, ZimingWang, YingweiWu, ChaoZhao, FenggangChen, LiangXia, WeiYan, JinChen, MinChen, Guoao
Under cyclic ultra-high-pressure impact loads, structures often experience local fractures due to insufficient initial fatigue life (low-cycle fatigue). This article focused on a certain ultra-high-pressure support structure and established a dynamic model based on load transfer characteristics to simulate the transient stress-strain response under impact loads. On this basis, a low-cycle fatigue life evaluation method was used to predict the fatigue life of the structure about 362 times, which was significantly different from the required indicators for structural fatigue life. In response to the problem of high loadbearing capacity on the structural support surface and significant stress concentration at the root, the structural load-bearing method has been optimized. Calculation analysis showed that after optimization, the structural stress was greatly improved, the bearing capacity of the support surface was reduced by 25 %, and the fatigue life of the structure was increased from 362 times to 4208 times, an increase of about 10 times. The optimized structure has been verified through 2000 tests without any fracture, meeting the requirements for the service life of the structure.
Wang, ShumanNing, BianfangMa, AminZhang, Fanfan
The six-degree-of-freedom Stewart platform, as a high-precision parallel robot, is widely used in fields such as aerospace and precision manufacturing. However, its complex structure and diverse sources of error (such as manufacturing errors, assembly errors, rod deformation, etc.) make it difficult to effectively control position and attitude errors. This article proposes a Stewart platform position and attitude error compensation method, relying on the improved particle swarm optimization algorithm. By establishing a position and attitude error model for the platform and optimizing the driving joint error using the IPSO optimization, the position and attitude error of the platform have been significantly reduced, providing a new solution for error compensation of high-precision parallel robots.
Zhu, MingWang, Baichao
To fulfill the multi-tube launch requirements for a specific folding-wing UAV, this study improves the structure of the existing storage-launch container. Based on the finite element method, a parametric model of the container is established, and a multi-condition mechanical analysis is carried out for various storage, transportation, and launch conditions. The difference between the first six natural frequencies of the free mode and the prestressed mode is compared and analyzed. The modal analysis model considering prestress is used to identify the optimization area of the container. The variable density method (SIMP) is used to optimize the topology of the container, with the volume of the container as the constraint condition and the minimum strain energy as the optimization goal. The optimization results show that the first-order modal natural frequency of the container is increased by 108%, and the first six natural frequencies are increased to a safe range, which effectively avoids the resonance risk. At the same time, the quality is reduced by 29%, and good optimization results are achieved.
Yuan, WeiyangJi, YuguoLiu, ZhipengYu, Wenxin
The suspended converter valve constitutes the fundamental equipment essential for the functioning of direct current power transmission infrastructure. The electrical equipment has been severely damaged in historical seismic events, underscoring the earthquake resistance of thyristor valve is critical for maintaining secure and consistent performance of energy delivery systems. Current seismic research focuses on ±800 kV converter valves, while studies on ±600 kV converter valves are lacking. Due to significant differences in the length of suspended insulators between ±600 kV and ±800 kV converter valves, their seismic responses differ considerably. A three-dimensional finite element model encompassing both the ±600 kV suspended converter valve and its supporting valve hall structure was developed to accurately capture their dynamic interactions under seismic excitation. The modal analysis is conducted, and the natural frequencies and mode shapes of converter valve and valve hall system are obtained. The seismic analysis results indicate that under 1 g seismic excitation, the calculated maximum seismic displacement of the suspended valve tower is 421 mm, exceeding the engineering design limit of 400 mm. The calculated minimum stress safety factor for the converter valve suspended insulators is 1.46, failing to meet the specified requirement of no less than 2. Both the swing amplitude of the converter valve and the stress on the suspended insulators exceed design limits. It not only poses a mechanical safety risk to the converter valve, but the excessive seismic displacement can also lead to seismic coupling effects between the converter valve and critical equipment. Therefore, further research on damping measures is required for the seismic vulnerabilities of ±600 kV suspended converter valves.
Lin, SenZhu, ZhubingLu, ZhichengSun, Yuhan
Vacuum laser welding trials were carried out on 42CrMo steel, a material widely utilized in the defense sector. By employing a 30 kW fiber laser system, complete penetration welds were successfully produced on 20 mm thick 42CrMo steel plates. The resulting joints displayed satisfactory surface quality on both the top and bottom sides, with no evident defects such as cracks or porosity. A comprehensive analysis of the joint microstructure and mechanical properties was conducted. Findings reveal that the weld zone (WZ) is predominantly composed of lath martensite, accompanied by minor quantities of plate martensite, organized as columnar crystals. The joints demonstrated high tensile strength at ambient temperature, with fracture consistently occurring within the base metal (BM). Microhardness measurements indicated higher values within the weld relative to the base metal, and no pronounced softening was detected in the heat-affected zone (HAZ). Additionally, the joints exhibited commendable impact toughness, suggesting overall superior mechanical performance.
Shi, HaichengZhang, GuoyuLi, WuhongCao, DongxuLiu, Tianlei
Addressing the inaccuracies in interface curvature computation using the Volume of Fluid (VOF) method and the lack of mass conservation in the Level Set (LS) method, a novel interface tracking method, the Coupled Volume of Fluid and LS (CVOFLS) method, is established. This approach synergistically integrates the strengths of both VOF and Level Set methodologies. It simultaneously solves for the VOF and LS functions based on fluid velocity, corrects fluid mass using the surface obtained by the VOF approach, and computes interface normals using the LS function, thereby eliminating the need for LS function reinitialization. This effectively overcomes the shortcomings of both methods. Numerical simulations of interface tracking demonstrate that the CVOFLS method ensures high tracking accuracy of free interfaces, good mass conservation, and improved computational efficiency.
Cui, LiyingSun, HuiXu, Wei