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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 steel in the form of wire.
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 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- and heat-resistant nickel alloy 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 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 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
To improve the mobility and reliability of special-purpose vehicles that are operated in extreme conditions and to minimize the influence of tire failure on the vehicle’s mobility, this paper investigates how the mechanical properties of honeycomb non-pneumatic tires are affected after high-speed impacts from external projectiles. A prototype of a network non-pneumatic honeycomb tire was initially developed, which was made of polyurethane material. The five parameter model of the Mooney-Rivlin model was selected as its constitutive relation and the experimental study was performed to validate three-dimensional stiffness simulation model for the tire. Secondly, a LS-DYNA-based finite element model was developed to describe the dynamic behaviors of the tire under an external impact at various locations (e.g. tread, single spoke plate and joints), and to investigate the influence of local damage and spoke plate fracture on the stiffness of the tire. The results indicate that the tire has better performance of resisting the impacts at small and medium levels, with the decrease of radial stiffness of the tire less than 4% after experiencing the ultrahigh load; after the spokes plate is broken, the radial stiffness of tire drops significantly by comparing with the intact tire, that is 24.17%, which has a great effect on the support performance of the tire. The findings of this work offer theoretical support and design guidelines for the structural optimization and properties improvement of NPTS.
Yao, TuzaoSun, XiaowangZhang, QiangFu, LeiHuang, Jianbin
The static-dynamic behaviors of ultra-precision five-axis machine tools are the core factors to ensure sub-micron-level machining accuracy. This study establishes a detailed finite element model of an entire machine based on the ANSYS Workbench platform and conducts in-depth research on the static-dynamic characteristics of the entire machine of the ultra-precision five-axis machining center by using the finite element analysis(FEM) method and combining the principles of statics and dynamics. By constructing an accurate finite element model, the stress distribution, deformation, and modal vibration characteristics of the entire machine, especially the key parts, such as spindle box, crossbeam, column, and guide rails, under complex loads such as gravity and cutting force are simulated. The static analysis reveals a maximum deformation of 0.17 mm in the spindle box and the column, and the maximum stress is 58 MPa (at the Z-direction guide rail contact point), which is lower than the allowable stress of Q215 steel (195.5 MPa). The modal analysis extracts the first six natural frequencies (50.683 - 175.91 Hz), and the low-order vibration modes are mainly the Y/X-direction swing of the column, revealing the weak stiffness links. Based on the analysis results, a parametric optimization method was further adopted to optimize the structure of the weak components: the base, the column and the spindle box. This significantly enhanced the overall stiffness, reducing the maximum deformation to 0.039 mm and the maximum stress to 45MPa. The first six natural frequencies were all greatly increased (the first one reaching 85.548Hz). These findings provide valuable insights for machine tool structural enhancement and performance optimization.
Li, ShanSohi, Seyed Hamed Hashemi
Ultrasonic guided waves enable long-range, low-intrusion inspection of pipelines. This study examines how array topology and axial spacing influence the quality of defect echoes when the longitudinal axisymmetric mode L(0,2) is used. We build COMSOL finite-element models of a steel pipe and excite it with PZT-4 at 80 kHz; three practical layouts are compared: (i) odd–even receiving, (ii) 8-transmit/8-receive, and (iii) 16-transmit/8-receive, arranged as two axially separated groups. The spacing between the groups is chosen to suppress parasitic modes such as L(0,1) and to strengthen L(0,2). Results show that the two-group configuration sharpens the defect echo and reduces modal interference; increasing the number of transmitters further raises the defect-wave amplitude and improves the separation from end-reflection echoes. Among the schemes, 8×8 performs well for small-defect identification, while 16×8 yields the clearest boundaries and fastest defect indication. These findings clarify how sensor number and placement govern modal purity and sensitivity, and they offer practical guidance for designing guided-wave arrays that improve the reliability of long-range pipeline inspection. - Ultrasonic guided waves Pipeline non-destructive testing L(0,2) mode; Sensor array layout; Finite element simulation; Guided wave signal processing.
Liao, WeiLi, TengfeiZhang, WenhuiLin, QingmingGuo, Yanbing
Ship propulsion shaft systems are subjected to ice load excitation when ships are navigating in polar ice regions. Compared to conventional hydrodynamic effects, the ice load imposes higher requirements on the shaft system’s ability to withstand torsional stresses. To improve the power of the ship propulsion system when sailing in ice areas and reduce the power loss of the shaft system, while considering the vibration performance. In this paper, a multi-objective optimal design of the shaft system is carried out using the Non-dominated Sorted Whale Optimization Algorithm (NSWOA) to reduce stresses on both the motor shaft and the intermediate shaft. The coupled system model of motor-shaft system-propeller structural components is established, and the system dynamics response model is obtained by solving using the Newmark-β method. Based on the response model, a multi-objective whale optimization algorithm is used to optimize the power and vibration performance of the shaft system simultaneously. The optimized results show that the shaft system transfer efficiency is improved by 0.27%, and the stress at the shaft end is reduced by 11.8% and 12.3% respectively.
Hu, ChuanxiLi, YaoPan, ShuxianLiu, ZhiyongXie, YutengYe, JunZhou, Ruiping
This study presents a refined design for pneumatic conveying pipelines, featuring a grooved structure at the bend aimed at reducing particle breakage during transportation. Using soybean particles as a focus, the research employs a gas-solid two-phase flow approach to explore how different groove depths and widths influence the breakage rate. We used CFD-DEM simulation techniques, combining fluid mechanics with discrete element modeling to achieve a more accurate representation of particle motion and collision forces during expressing. Based on these simulations, we identified the most effective combination of groove width and spacing. Experimental results showed that a groove width of 4.5 mm coupled with a 40 mm spacing could decrease impact forces on particles by approximately 5% to 10% at expressing speeds of 15 m/s and 20 m/s. Throughout all measured time intervals, the impact forces remained stable, with turbulence exerting minimal influence on the particle forces.
Luo, XinhaoYang, TianchengHuang, BoMao, GenwuDong, DeliangShi, HengLi, XiaoliangHe, Bo
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