This study examines oil jet lubrication of an engine spiral bevel gear set using numerical simulation, analytical modelling, and experiments. A 3D Moving Particle Semi-implicit (MPS) model is built in shonDy software to describe the transient jet and free surface flow around the rotating gears. The numerical results are coupled with analytical expressions for frictional heat generation, elastic fluid dynamic film thickness, and convective heat transfer. This combined model yields the oil coverage on the tooth surfaces, the pressure distribution, and the local heat transfer coefficient. An orthogonal experiment is carried out on a dedicated test rig to measure torque loss and to validate the trends obtained from the simulations. The influence of injection distance, injection angle, nozzle diameter, and gear speed is studied. The results show that nozzle diameter and gear speed have the strongest effect on oil coverage, heat transfer, and torque loss. The injection angle mainly changes the distribution of oil and temperature, while the injection distance has a limited effect within the tested range. The integrated numerical and analytical approach, supported by experiments, provides a practical tool for the design and optimization of jet lubrication for spiral bevel gears. It is suitable for high-speed gearboxes.

To improve gear lubrication efficiency, this paper designs a new arc groove gear structure and proposes an optimised nozzle arrangement based on it. Firstly, the effect of nozzle arrangement on tooth surface temperature is studied through simulation analysis. The results show that under the NO1-NO16 nozzle layouts, the tooth surface temperature of the arc groove gear is lower than that of conventional gears. Among these, the NO13 nozzle layouts offers the best cooling efficiency and lubrication effect, reducing tooth surface temperature by 10.21 K compared to conventional gears and increasing cooling efficiency by 3.29%. Secondly, under NO1-NO16 nozzle layouts, oil volume fraction in the meshing zone of the arc groove gear significantly exceeds that of conventional gears, specifically, nozzle layout NO13 achieves a 10.88% higher oil volume fraction and a 74.77% increase in oil utilisation rate. Finally, orthogonal experiment analysis reveals that among the 16 layouts, NO13 has the smallest tooth surface temperature difference-reducing it by 9.8 degrees C compared to conventional gears-and increases heat dissipation efficiency by 24.20%. The optimal nozzle parameters are: injection distance of 60 mm, injection angle of 15 degrees, nozzle diameter of 3.5 mm, and speed of 2500 r/min. The order of influence on tooth surface temperature is: nozzle diameter > injection distance > rotation speed > injection angle.

Rolling contact connector (RCC) is widely used in aerospace and industrial fields, with reliability analysis and optimization being critical for their structural design. This study proposes a reliability analysis and optimization framework for RCC utilizing a multi-level sparse adaptive Monte Carlo simulation (MLS-AK-MCS) combined with Kriging models. The approach enhances computational efficiency and accurately identifies high-risk regions by applying a global Kriging model for overall trend description and local models for detailed risk analysis. The method reduces unnecessary conservatism and optimizes the structural design of RCC, ensuring optimal performance while maintaining reliability. An application of this framework to a flexible ring design, under a failure probability threshold of eta = 0 .03, demonstrated a maximum compressive stress of 202 MPa and a contact resistance of 40.54 mu Omega, with negligible deviations from theoretical predictions (0.26 MPa and 1.30 mu Omega). The MLS-AK-MCS method not only improves reliability assessments but also optimizes material usage and performance margins, laying the groundwork for next-generation structural designs. While the current study focuses on the RCC case, the proposed framework is extendable to other structural reliability problems with similar modeling challenges.

Based on the COMSOL Multiphysics simulation platform, this paper establishes a complete finite element model of a power roll ring assembly. The model consists of inner and outer conductive rings made of H62 brass and a flexible ring made of C17200 beryllium bronze. After meshing, a rotational speed was applied to the inner conductive ring according to actual working conditions, and consistent boundary conditions and friction coefficients were set at the contact pairs for transient dynamic analysis. The study focuses on investigating the influence of the flexible ring’s fillet length (0.15 mm, 0.20 mm, 0.25 mm, 0.30 mm, 0.35 mm) on the system’s contact characteristics and motion stability. By analyzing stress nephograms, motion trajectory diagrams, and quantitatively calculating contact pressure, the results show that the maximum contact stress of the flexible ring is concentrated at the contact points with the inner and outer conductive rings and increases with the fillet length. However, the contact pressure decreases as the fillet length increases, with small fluctuation amplitude, ensuring the operational stability of the power roll ring. This research provides a theoretical basis and an effective method for the structural optimization and performance evaluation of power roll rings.

This paper adopts the method of ultrasonic-assisted abrasive flow precision machining to study the ultrasonic-assisted abrasive flow precision machining of high-performance ceramics. Taking zirconia ceramic tubes as the research object, the influence laws of different inlet pressures, abrasive concentrations, and ultrasonic frequencies on the precision machining effect of high-performance ceramics are analyzed. The laws of ultrasonic-assisted abrasive flow precision machining of high-performance ceramics under different inlet pressures, abrasive concentrations, and ultrasonic frequencies are obtained. Through orthogonal experiments on the ultrasonic-assisted abrasive flow precision machining of high-performance ceramics, it is found that ultrasonic-assisted abrasive flow precision machining can effectively remove the strip-shaped grooves, protrusions, and depressions on the inner surface of ceramic tubes. The inner surface roughness Ra of the ceramic tube can reach 0.101 mu m, which can effectively improve the surface quality of the inner surface of the ceramic tube. It is proved that ultrasonic-assisted abrasive flow can precisely machine high-performance ceramics, providing technical support for ultrasonic-assisted abrasive flow precision machining of high-performance ceramics.

Friction and wear are key issues in gear meshing. Lubrication, therefore, is used to reduce heat. The position and direction of the flow of the lubrication determined by the way the nozzles are injecting the fluid and by the texture on the flanks of the teeth, both have an influence on the heat transfer. Furthermore, the geometric characteristics of the tooth texture influences the friction behaviour directly. This article presents investigations on the impact of the tooth texture on wear. A proposal to prepare the tooth flanks with arc shaped grooves is made presenting the manufacturing process. Different measurements to determine the tooth flank texture and the friction are performed. Measurements showed that the arc groove gear had lower friction coefficients, wear depth, surface roughness Ra, and maximum tooth profile peak height Rq compared to conventional gears. The dynamic process of gear meshing is simulated by FEM analysis to understand the physics of heat flow and friction in detail, which revealed that the arc groove gear had reduced sliding distance, contact pressure, and wear depth, along with a higher convective heat transfer coefficient. Based on the measurement results of orthogonal test, two different nozzle arrangements are predicted: one is linear regression prediction (nozzle arrangement (A), and the other is nonlinear particle swarm optimization neural network prediction (nozzle arrangement (B). By measuring the torque loss value under the two nozzle arrangement conditions, it is found that the nozzle arrangement B is the best arrangement. The specific parameters are: injection distance is 56.0674 mm, injection angle is 8.4527 degrees, nozzle diameter is 3.3955 mm, and pinion speed is 3000 r min-1. Under this condition, the mechanical efficiency loss is reduced by 94.48%.

Calcium fluoride crystals play an irreplaceable role in practical applications and scientific theoretical research due to their physical and chemical properties, excellent optical properties, and structural characteristics. In order to obtain the surface of the calcium fluoride crystal with low damage, this paper expounds the basic theory of magnetohydrodynamics and the principle of magnetorheological machining removal, combining numerical simulation and experimental analysis of the role of different polishing speed, abrasive grain concentration, excitation gap on the calcium fluoride crystal surface of the wall shear force, and dynamic pressure distribution, to explore the influence of the process parameters. The orthogonal test method was used to study the process of abrasive flow machining of transmission gears, and finally the polishing speed was analyzed as the factor with the most significant influence among the three factors. The surface roughness was improved from 0.036 to 0.029 µm on the final calcium fluoride crystalline material, resulting in a desirable flat surface. The feasibility of the magnetorheological polishing technique for ultra-precision machining of calcium fluoride crystals is verified. It provides technical support for the actual magnetorheological polishing technology for processing calcium fluoride crystal materials.

Al-Ni alloy is widely used in the aerospace field. In order to further study the nanoindentation deformation mechanism of Ni–Al alloy, the [001] and [111] crystal phase models of single crystal Ni–Al alloy were established, and the mechanical behavior was systematically analyzed by molecular dynamics simulation method. The hardness data of the material were obtained by comparing the indenter load–displacement curves of the two models. Combined with atomic-scale microstructure analysis, it was found that the single crystal nickel-aluminum alloy [001] phase exhibited higher hardness and larger stacking height. In contrast, the [111] crystal phase produces more dislocation loops during the deformation process, and the stacking width is larger, forming a complex cross-linked network structure. This structure promotes the occurrence of dislocation slip, thereby reducing the overall hardness of the material. The influence of different crystal phases on the mechanical properties of nickel-aluminum alloy is revealed from the microscopic mechanism, which provides an important theoretical basis for optimizing the performance design and engineering application of nickel-aluminum alloy materials.

Purpose Optimizing pipeline layouts in complex three-dimensional (3D) environments remains challenging due to dense equipment, intricate structures, and high pipeline density. To address these issues, this study proposes a novel Quantum-Inspired Simulated Annealing (QISA) algorithm that integrates quantum superposition and tunneling effects into a simulated annealing framework. Design/methodology/approach The algorithm enhances global search capabilities by efficiently exploring the solution space and mitigating local optima entrapment. Comparative experiments with traditional methods—Particle Swarm Optimization (PSO) and the A* algorithm—demonstrate QISA's superiority. Findings Specifically, QISA reduces pipeline length by 9.4%, decreases the number of bends by 15.6% and lowers installation costs by 7% compared to PSO and A*. These improvements highlight QISA effectiveness in optimizing pipeline layouts while reducing project complexity in 3D environments. The proposed algorithm offers a robust tool for automated pipeline routing, advancing the field through quantum-inspired principles and practical applicability in industrial settings. Originality/value This study introduces a novel approach to automated pipeline routing by integrating quantum-inspired principles into a simulated annealing framework. The proposed QISA algorithm offers a significant advancement over traditional methods, providing a powerful tool for optimizing pipeline layouts in highly complex 3D environments.

This paper proposed an ultrasonic-assisted abrasive flow machining (AFM) method for precision processing to enhance the surface quality of the inner surface of ceramic bearing outer rings. Through a combination of numerical simulation and experimental verification, this study systematically analyzed the influence of three key process parameters-feed pressure, abrasive concentration, and ultrasonic frequency-on the machining results. The results indicated that optimizing the flow channel structure and incorporating an internal contour core effectively improved particle distribution uniformity and machining stress. Appropriately increasing feed pressure and abrasive concentration while reducing ultrasonic frequency facilitated smooth particle flow in recessed areas, thereby achieving higher uniformity in precision machining. Experimental results showed that under the optimal parameter combination (feed pressure of 4 MPa, abrasive concentration of 50%, and ultrasonic frequency of 20 kHz), the surface roughness Ra value of the ceramic bearing decreased from the initial 1.077 mu m/1.072 mu m to 0.101 mu m/0.122 mu m, significantly improving surface integrity. Numerical simulations further revealed that the ultrasonic waves increased the kinetic energy and collision frequency of the abrasive particles, effectively enhancing material removal rate and processing efficiency. This study not only validated the advantages of ultrasonic-assisted AFM technology in the precision processing of ceramic materials but also provided theoretical insights into its kinetic mechanisms and process optimization.

The surface quality of high-performance impellers, which feature complex, free-form surfaces and narrow flow channels, is critically important for their performance and efficiency. However, achieving uniform precision polishing on these intricate geometries remains a significant manufacturing challenge, as traditional methods are often inefficient, inaccessible, or cause surface damage. To address this, this study investigates the application of solid–liquid two-phase abrasive flow machining (AFM) as a high-precision finishing solution. Through numerical simulation, we analyzed the polishing effects under two flow channel structures and various machining parameters. The results demonstrate that a gradual flow channel structure significantly enhances processing uniformity and intensity compared to a direct flow channel. Furthermore, increasing the inlet pressure and abrasive viscosity was found to substantially improve both the strength and uniformity of the machining effect across the impeller surface. Experimental validation via an orthogonal test design confirmed that inlet pressure is the most influential factor on the polishing effect, followed by abrasive grain size and the number of processes. The optimized process parameters (6 MPa inlet pressure, 10 process cycles, and 40 µm abrasive grain size) successfully reduced the average surface roughness (Ra) of the high-performance impeller from 0.766 µm to 0.047 µm, representing an improvement of nearly 94%. This study provides a scientifically grounded set of optimal parameters for achieving uniform, high-quality surface finishing of complex impellers using AFM technology.

Gears play an important role in modern machinery and are indispensable transmission components, particularly at high speeds, where lubrication is essential for the reliability and efficiency of the gear unit. In order to study the oil coverage law and heat dissipation mechanism of high-speed rotating meshing gears by injection angle, this paper adopts the moving particle semi-implicit method to establish a high-speed rotating gear lubrication model, study the intrinsic effect of different jet angles on gear lubrication, and build a gear lubrication bench for experimental verification. Numerical simulation found that with an increase in spray angle, the gear surface coverage and heat transfer coefficient of the high-speed rotating transmission gears initially increase and then decrease. They reflect the same lubrication law characteristics. When the injection angle was 90°, the surface coverage and heat transfer coefficient values were at their greatest, resulting in the best spray lubricating effect. According to the experimental results, under the conditions of 0.5 MPa injection pressure and high-speed rotation of the transmission gear with vertical injection, the lubricant covers the largest surface area of the gear and the least power loss. Simultaneously, in our previous study, we experimentally obtained the optimal parameter conditions on the basis of which we derived. The effect of nozzle diameter on jet lubrication was investigated in a previous study, and in this article, the effect of nozzle angle and distance on gear lubrication is investigated; the optimal conditions for high-speed lubrication of gears are the incident distance of 3.5 cm, incident angle of 90°, incident diameter of 1.5 mm, and gear speed of 2000 r/min, and the lubrication effect reaches the best ideal state; reduction in oil loss due to oil injection lubrication and power loss due to different parameters of the lubrication system. Lubrication design provides a theoretical foundation for the transmission system.

Focused on the lubrication optimization challenge in gear transmission systems, this paper introduces a novel approach involving the coordinated adjustment of bionic textures and nozzle arrangement. By analyzing the surface texture characteristics of scallop shells, a bionic textured tooth surface is designed to improve oil film formation. The impact mechanism of texture parameters on the oil film coverage of the tooth surface is explored through the integration of the MPS (Moving Particle Semi-Implicit Method) numerical simulation technique. Based on orthogonal experiments, the influence patterns of nozzle layout parameters on power loss are examined, leading to a substantial reduction in gear pair power loss. The findings indicate that, compared to conventional gears, the mean oil film coverage rate of the bionic gear under different nozzle layout conditions increases by 13.26% to 47.01%, while power loss decreases by 8.83% to 36.68%.

Mg-Li alloy is widely used in aerospace and military equipment, but the research on its micromechanical mechanism is still insufficient. In this paper, molecular dynamics simulation is used to analyze the nano-indentation response and mechanical mechanism of single crystal Mg-Li. The deformation and hardness changes of Mg-Li under different loads were studied by load–displacement and hardness–depth curves. At the same time, the dislocation defects and equivalent stress are analyzed to reveal the dislocation formation and stress distribution in the process of deformation. Finally, under the condition of stress relaxation, the mechanical behavior of Mg-Li in the process of nano-indentation was revealed, and the deformation mechanism of Mg-Li alloy was studied.

Conductive slip rings (CSRs) are precision components critical to industrial equipment, yet they face challenges such as unstable signal transmission, limited functionality, and difficulties in operational monitoring due to assembly-induced inaccuracies. This study proposes a hollow-type integrated assembly solution, incorporating optimized transmission, clamping, and protection modules through structural design and modular analysis. Static and dynamic simulations identify the optimal assembly angle and connector configuration (hollow-type outperforming flange-type), ensuring reliability and stability. A high-precision universal assembly platform is designed, and an R-axis rotary table-based testing method is developed to evaluate transmission and fixation modes. Results demonstrate the superiority of sleeve couplings and hollow connectors, with the assembled system achieving contact resistance fluctuations below 10 mΩ, angular repeatability under 500″, and accuracy within 720″, meeting all design specifications. The proposed framework combines simulation-driven design with experimental validation, offering a robust approach to enhance the performance of CSRs in industrial applications.

Observing the intricate microstructure changes in abrasive flow machining with traditional experimental methods is difficult. Molecular dynamics simulations are used to look at the process of abrasive flow processing from a microscopic scale in this work. A molecular dynamics model for micro-cutting a single crystal γ-TiAl alloy with a rough surface in a fluid medium environment is constructed, which is more realistic. The evolution of material removal, cutting force, temperature, energy, and dislocation during micro-cutting are analyzed. The impact of cutting depth, abrasive particle sizes, and abrasive material on the micro-cutting process are analyzed. The analysis shows that the smaller cutting depth and abrasive particle sizes are beneficial to obtain a better machining surface, and the cubic boron nitride (CBN) abrasive is an effective substitute material for diamonds. The purpose of this study is to provide unique insights for improving the material removal rate and subsurface quality by adjusting machining parameters in actual abrasive flow precision machining.

This study employs molecular dynamics (MD) simulations to investigate the nano-scale current-carrying friction and wear behavior of copper/graphite conductive slip rings under varying electric field strengths, normal loads, and sliding velocities. A three-layer MD model comprising graphite, an air gap, and a copper substrate was constructed using Materials Studio and simulated via LAMMPS. Results show that increased electric field strength, load, and sliding speed exacerbate friction force and energy dissipation, while lower parameter values promote the formation of stable tribochemical films and enhance anti-wear performance. These findings provide theoretical guidance for optimizing conductive slip ring design in high-reliability industrial applications.

TiN thin film coatings are used to improve the surface hardness of materials. To avoid affecting the shape and size of the workpiece, the coating thickness is usually in the micrometer range. During nanoindentation experiments, the deformation of the material will not be affected by the mechanical properties of the substrate under small indenter load, which is equivalent to the nanoindentation test of the bulk TiN material. Due to the small indentation depth, it is difficult to observe the material deformation and the nucleation and evolution of material defect structures during the experiment. Therefore, molecular dynamics simulation of the nanoindentation process of single-crystal TiN material is an important means to study the nanoindentation deformation mechanism of bulk TiN material. The objectives of previous studies have focused on validating models, calculating specific performance parameters, observing a particular phenomenon, and investigating the influence of a single factor. The present study focuses on the systematic exploration and revelation of the mechanism itself, especially incorporating multiple dimensions such as crystal orientation, depth, and dynamic relaxation behavior. Two kinds of TiN molecular dynamics simulation models with two crystallographic orientations were constructed, and after the model reached equilibrium in the relaxation phase, the single-crystal TiN material was simulated at different indentation depths, the stress relaxation characteristics of the material investigated in the case of different depths, the mechanical property parameters exhibited by load–displacement curves and the defect evolution forms derived from the analysis of the simulation results analyzed, so as to reveal the single-crystal TiN material from the atomic scale The nanoindentation deformation mechanism of single-crystal TiN material has been revealed on the atomic scale.

Heat dissipation efficiency and wear resistance in the lubricated contact area should be optimized to enhance the service life of the gear. In this study, bionic gear samples were designed following bay scallop texture features. Test results suggest that ordinary gears under lubricating conditions presented a higher friction coefficient compared to vertical groove gears and arc groove gears. Among them, the arc groove gear NO116 possessed the lowest friction coefficient at 0.14987, which was 16.39% lower than that of ordinary gears. Under the consideration of identical texture parameters, arc groove gears displayed lower friction coefficients across 16 groups compared to vertical groove gears. Additionally, finite element analysis reveals that both vertical and arc groove gears exhibited curtailed wear depth and average temperature compared to ordinary gears. Additionally, finite element analysis reveals that both vertical and arc groove gears exhibited curtailed wear depth and average temperature compared to ordinary gears. The arc groove gear NO116 had a wear depth of only 5.04 mu m, indicating a reduction of 74.42% compared to ordinary gears; its average tooth surface temperature was 35.05 degrees C, with a decrease of 5.56% compared to ordinary gears' temperatures. Furthermore, the wear depth testing results unveil that among the 32 groups of bionic textured gears, the arc groove gear NO116 demonstrated minimal wear depth at 5.029 mu m, which brought a reduction of 74% from ordinary gears. Thermal imaging further implies that arc groove gear NO116 experienced a maximum tooth surface temperature of 38.70 degrees C, dropping by 3.49% compared to ordinary gears' temperatures.

The MPS particle method is employed to simulate the tooth surface pressure of textured gears. Among these, the NO114 gear exhibited the lowest tooth surface pressure. However, the lubrication performance achieved using empirically designed texture patterns was not optimal. Consequently, Therefore, the texture parameters of the tooth surface are optimized through the particle swarm optimization algorithm to reduce the pressure of the tooth surface. Through iterative calculations, the following optimal texture structure was obtained: Texture depth = 225.0000 μm, texture width = 219.6372 μm, texture spacing = 251.0522 μm, and texture length = 1629.9608 μm. The fitting degree between the average tooth surface pressure and the predicted value reached 98.765%. Compared to the NO114 arc groove gear, the optimized arc groove gear showed a reduction in average tooth surface pressure by 0.00019904 MPa.