Browse Topic: Manufacturing processes

Items (22,897)
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
This study explored the relationship between the placement roller and the radius of curvature of the mold. In the production process, it is better to judge the feasibility of placement based on the actual placement profile. It is calculated that when the prepreg with a tow width of 6.35 mm is used for automatic fiber placement and forming, the 4-tow, 8-tow, and 16-tow laying rollers can be laid at a maximum depth of 2 mm. The formulas for the length of the automatic fiber placement roller and the axial radius of curvature of the die are obtained. At the same time, through geometric analysis, a formula for calculating the minimum radius of curvature of the pressure roller is obtained. The finite element software Abaqus was used to simulate the contact of the 4-tow, 8-tow, and 16-tow laying rollers with the minimum axial critical radius of curvature at a 2 mm depth, and output the force curve of the node where the mold surface contacts the pressure roller. It is found that the simulation results are consistent with the calculation results.
Ma, ChengXiu, ZhifengXue, HongmingYang, MaoweiZhang, Pin
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
To address the challenge of accurately assessing the reliability of complex equipment, a reliability evaluation system for a five-axis machining center was developed based on extension theory. By collecting and analyzing the failure modes and data of various subsystems, the strengths of the Fuzzy Analytic Hierarchy Process (FAHP) and the Entropy Weight Method (EWM) were combined to determine the weight of reliability evaluation indicators for both the machining center and its subsystems. A comprehensive assessment of the five-axis machining center's overall reliability was conducted. According to the principle of maximum membership, the reliability grades for the spindle system and the feed system were both rated as “excellent.”
Fei, ShouxiangWang, DechaoPiao, ChengdaoZheng, Shengkui
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
This research demonstrates a facile method for fabricating an anti-icing coating through spray deposition on a metallic substrate. A dual-layer structure was designed to enhance icephobic properties: a primer layer incorporating fluorocarbon resin, butyl acetate, and rod-shaped micrometer-sized metal oxides to establish a secondary roughness morphology, followed by a topcoat composed of butyl acetate and nano-scaled superhydrophobic particles. Evaluation of the coating performance revealed a maximum water contact angle of 171.9°, indicating exceptional hydrophobicity. Furthermore, the coating exhibited notable abrasion resistance and anti-icing capabilities against overlaying ice.
Li, DongyangXu, ZelongWu, JiangTong, WeiWang, WeiqingCong, RimeiQian, JiaweiQu, Shaohui
Based on the principle of the bimetallic effect of the electrothermal microdrive, polymer SU-eight glue is used as the functional material, nickel metal is used as the structural material, and copper metal is used as the sacrificial layer to make the electric heating microdrive. We process and manufacture them based on specific MEMS processes such as lithography, mask plating, and magnetron sputtering, and perform basic characterization, observation, and electrical signal analysis on the samples. The results show that the overall electrothermal micro-driver device is complete, the electrode and resistance wire structure is complete, and the I-V signal is normal.
Xue, YunhaoTan, XiaolanJiang, Xin
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
The cutting machine is a critical component in the cigarette processing line, and its cutting quality depends on the operational condition of the copper bar chain. The grooves on the surface of the copper bar chain accumulate dust during the operation of the machine, which often causes unstable conveyance of raw materials, significant width variations, and a high defect rate. To address this issue, this study developed a linear reciprocating automatic cleaning system for copper bar chains to remove dust from the groove surface and hinge joints. Experiments have verified that the system improved the cutting qualification rate, increased the operational stability of the cutting machine, reduced manual cleaning workloads, and reached higher cleaning efficiency. This innovative system is also expected to provide a valuable reference for similar equipment manufacturers and advance technological innovation in the cigarette processing industry.
Li, HaitaoZhang, ChunyuanFang, JunqingSu, LinChen, PengGuo, ZhiweiXing, Dongdong
Desulfurization equipment in electric power industry is in a multi-field coupled corrosion environment with high temperature, high humidity, strong acid and solid-containing slurry. The annual direct economic loss of corrosion exceeds 5 billion yuan, and the equipment replacement cycle is only 1.5-2 years. Traditional protective coatings are difficult to meet the needs. The concept of “bionic barrier-intelligent response-in-situ purification” is proposed to construct multifunctional protective coatings: The Langmuir-Blodgett technique was used to alternately assemble MXene nanosheets and polysilazane. Ti-O-Si covalent bonds enhanced the interface bonding, resulting in a coating hardness of 4H and an elongation of 200%. After 1500 hours of extreme environment test, the coating has low weight loss rate, high self-repair and antibacterial rate, and its service life is extended by 8 times. The engineering application makes the maintenance period of desulfurization tower of a 660MW unit extended from 8 months to 6 years, saving 1.2 million yuan annually, and increasing 200,000 yuan annually by recovering H ˇ SO 2. It provides a cross-scale scheme for electric power corrosion protection.
Nie, PengfeiGao, JiangyuChen, Wei
Electronic substrates and copper-clad laminates are widely used in modern life, particularly in electronic products such as coastal communication base stations and ship communication and navigation system. In these environments, salt particles carried by sea fog can adhere to the surface of the substrates along with moisture, leading to salt-alkali corrosion of the products. As a core material in electronic components, electronic-grade glass fiber urgently requires investigation into its durability under salt-alkali conditions. Therefore, this study focuses on a specific type of electronic-grade glass fiber and explores its corrosion behavior in three different environments: 2 mol/L NaOH, 1 mol/L cement solution, and 3.5 % NaCl. Soaking durations of 6, 12, 24 hours and 3, 7, and 14days were selected as key parameters. The mechanical properties and surface morphology of the fibers before and after corrosion were observed and analyzed. Experimental results indicate that the glass fiber exhibits higher durability in saline solutions than in alkaline environments. This study provides theoretical support for evaluating the long-term performance of Electronic grade glass fibers in practical applications. It also contributes to the optimization of raw materials and manufacturing processes, enhancing the performance of such fibers in salt-alkali conditions, and offers valuable reference for future research on glass fiber-reinforced composites.
Pu, QixinSun, SiqiFang, QiangDong, ShuoLi, PengWang, YuZhang, MengxuanZhang, YuboYang, WenfengGuo, Peng
Thin-walled structures with weak stiffness are widely applied in aerospace, precision machinery, and mold manufacturing; however, their machining processes are commonly challenged by insufficient rigidity, complex dynamic characteristics, and a high susceptibility to chatter. Due to the differentiated dynamic parameters of these structures at various spatial positions, the compliant interaction between the tool and workpiece during milling significantly increases the risk of chatter, thereby degrading machining precision, surface integrity and productivity. To this end, this research establishes a three degree of freedom (3-DOF) milling process dynamics model based on the full discretization method (FDM), which systematically obtains the modal parameters of the thin-walled component at different locations. Building upon this, position-dependent stability lobe diagrams for milling prediction are constructed to theoretically reveal the influence of local structural regions on milling stability. Furthermore, this paper proposes a multivariate nonlinear regression method to establish a nonlinear identification model for milling force coefficients. Key parameters were effectively identified through experiments, predicting the variation trends of force coefficients under different cutting conditions. Subsequently, cutting experiments were conducted across different spatial regions of the thin-walled structure to comparatively analyze stability performance under various combinations of cutting parameters. The results demonstrate that the established dynamic model and force coefficient identification method can effectively predict the milling stability of weak-stiffness structures at different physical locations and can well explain the spatial distribution characteristics of cutting chatter. This research proposes a novel method for position-dependent milling stability prediction, providing a theoretical foundation and experimental data support for resolving the issue of frequent chatter at different locations on weak-stiffness structures in practical machining, which holds significant engineering value for the efficient and stable processing of complex thin-walled components.
Xi, ChenhuiZhao, YongshengXu, JingjingGao, Pengfei
This paper examines the temperature distribution during pipe cutting and the impact of the heat-affected zone on the mechanical microstructure and properties of steel pipes. Utilizing testing equipment such as K-type thermocouples, a MESTL-WELD thermocouple spot welding machine, and a DC5516H 16-channel temperature data logger, temperature tests were conducted on Φ 1016 × 17.5 mm X70M spiral seam submerged arc welded steel pipes and Φ 1016 × 21 mm X70M straight-seam submerged arc welded steel pipes. The results indicate that the maximum test temperatures during cutting were 953.8 °C and 1216.6 °C, respectively, with the duration of temperatures exceeding 400 °C at each test point not exceeding 30 seconds. By fitting the relationship curve between the peak temperatures of each test point and the cutting distance using the ExpDec3 model, it was found that the cutting distance corresponding to a temperature of 580 °C was 12 mm. Furthermore, mechanical microstructure and property tests were performed on the pipe body at different positions of the HAZ. Except for an anomaly in the yield strength of the rod-shaped tensile specimens of the Φ 1016 × 21 mm X70M welded pipe body, no other abnormalities were detected. Macroscopic metallographic examination revealed that the axial length of the HAZ at the end of the cut pipe did not exceed 7 mm. Microhardness testing showed significant fluctuations in the microhardness of the pipe body at the end of the cut pipe, while the microhardness of the pipe body beyond 10 mm from the end gradually returned to normal.
Xu, YanBai, QiangFeng, ZhenjunChang, YonggangLi, LiangPeng, Shibi
With the increasing demand for material microimaging analysis, there is a growing need for advanced precision grinding and polishing equipment, especially for metals, ceramics, and composites. Existing automated systems struggle with handling complex material challenges. This paper presents a fully automated adaptive grinding and polishing machine based on an STM32 microcontroller that handles multi-material samples. The system includes modules for sample access, cleaning, pad replacement, human-computer interaction, and equipment communication. The STM32 microcontroller executes grinding and polishing tasks based on instructions from the host computer while dynamically adjusting PID control parameters using an improved weighted average optimization algorithm. This approach enhances control accuracy, stability, and overall surface treatment quality compared to traditional PID control methods.
Zhang, LongqingKong, XiangyuZhao, XiuyangLi, Xingbei
With the development of controlled nuclear fusion technology, the tokamak device, as the most promising magnetic confinement fusion reactor for advanced engineering applications, requires remote maintenance of its internal components, which has become a key factor affecting both operational efficiency and safety. As a critical component directly exposed to high-temperature plasma, the divertor target plate needs to be periodically replaced and carefully maintained to ensure stable and reliable reactor operation. However, this region is subject to extreme conditions, including high temperature, high vacuum, and intense radiation, making conventional manual maintenance infeasible. This necessitates the development of intelligent and automated teleoperation systems. To address the automated assembly and disassembly requirements of divertor target plates, this study designs an integrated target plate actuator comprising key functional units: a positioning module, a screwing module, a quick-change module, and a passive compliance structure. The actuator achieves rapid and precise alignment with target plate holes, accommodates bolts of different specifications, and exhibits excellent impact resistance. Furthermore, stiffness and mechanical analyses, supported by finite element simulations, verify the actuator’s safety and reliability under high loads and impact forces. To further enhance operational performance, a segmented disassembly and assembly control strategy based on reinforcement learning is proposed, enabling the actuator to adaptively handle torque variations and ensure precise and stable bolt operations. The results demonstrate that the proposed actuator and control strategy significantly improve the accuracy, stability, and efficiency of target plate operations under complex working conditions, providing a reliable solution for automated divertor maintenance in tokamak devices.
Zang, XizheYu, XingzuCao, Zhangbin
This study investigates the interaction mechanism between ultraviolet nanosecond pulsed lasers and polyetheretherketone (PEEK). By integrating finite element simulations with experimental validation, the work explores the laser microtexturing characteristics of PEEK surfaces and evaluates the influence of microtextures on the material’s surface biocompatibility. First, the interaction between the laser and the PEEK polymer was analyzed, and a laser ablation model was established using the COMSOL Multiphysics simulation platform. Using finite element simulation, the effects of spot overlap ratio were investigated by adjusting the average laser power, while the influence of single-pulse energy on the ablation characteristics of the PEEK surface was examined by varying the scanning speed. Subsequently, ultraviolet nanosecond laser processing experiments were conducted on planar PEEK microtextures based on the simulation results. Taking surface microgrooves on PEEK as representative structures, the variations in groove depth and width under different combinations of laser parameters were analyzed. The parameters, including average laser power, scanning speed, and repetition frequency, were optimized to identify processing conditions that yield stable depth and width, along with good surface flatness. Finally, experiments have initially verified that the microtextured PEEK surface may improve biocompatibility and regulate surface wettability to a certain extent.
Wu, YifanWang, XiaohuiHan, YujieJin, Shuo
Weld residual stress is a critical factor affecting the structural integrity and service life of wind turbine towers. In this study, a systematic investigation was conducted on the residual stress distribution and control methods for door corner welds of an in-service wind turbine tower after approximately 20,000 hours of operation. X-ray diffraction (XRD) measurements revealed significant tensile residual stress in the weld and heat-affected zone, with peak values reaching 315 MPa, particularly concentrated at depths of 5-7 mm. To mitigate these stresses, two post-weld treatment methods were employed: ultrasonic impact treatment (UIT) and localized heat treatment. UIT effectively transformed surface tensile stress into compressive stress, achieving a maximum compressive residual stress of -372 MPa within a depth of 3 mm, while simultaneously refining grains and increasing surface hardness. In contrast, localized heat treatment at 460 °C for 5 hours led to a broader stress relief effect, reducing residual stress by approximately 100 MPa without causing significant changes to the macrostructure, but inducing substructural rearrangements beneficial for stress relaxation. Mechanical testing confirmed that both treatments improved tensile strength, ductility, and toughness of the welds. The combined findings demonstrate that ultrasonic impact treatment is highly effective for enhancing fatigue performance at the surface, while localized heat treatment offers advantages for deep stress redistribution and long-term structural stability. This comprehensive approach provides valuable technical guidance for residual stress management in complex welded structures of wind turbine towers.
Sun, WantingZhong, ZhenqianZhang, BoLiu, Hui
Considerable the gallium-based alloys low melting point coupled with easy to synthesize intermetallic compounds with diverse metallic elements, employing liquid gallium-based alloys as the soldering medium and leveraging ultrasonic as assistance are effective to construct pure copper joints under atmosphere condition. The investigation delves into the characterization of the reaction products, interface microstructure, elemental distribution patterns, and evolution of shear strength within the welds. Furthermore, the pivotal role of ultrasonic waves and constituent element diffusion mechanisms during the solidification phase is elucidated. Thus, the initial one-day occurred during solidification showed the 2.6 MPa shear strength but with the time increased to four and a half days, the shear strength raised to 8.4 MPa at room temperature. Thereinto, the results indicate the weld seam has achieved metallurgical connection. This innovative welding technique operates at room temperature provides significant guidance for designing a novel perspective low-temperature joining for applications. It is not only augments the repertoire of material connection methodologies but also presents a viable joining strategy for sensitive elevated temperature materials. Therefore, such process possesses substantial practical significance and promises avenues for future applications.
Guo, ManyingQu, YingyingFang, QiuyueYang, Shen
Driven by increasing engineering demands, the need for high-performance flexible electronics has surged, accelerating the development of stretchable devices within mechanics. Among multilayer structures, the film/substrate architecture serves as a typical example, and its buckling behavior remains a longstanding focus of mechanical investigation. This work examines how an elastic film bonded to a soft tri-layer substrate loses stability, producing wrinkled surface patterns under compression. We first construct a mechanical model, then derive an analytical expression for the wrinkle amplitude using a force-balance approach, and finally employ finite-element simulations and theoretical comparisons, we systematically explore how the middle layer’s stiffness and thickness jointly govern the onset, wavelength and amplitude of surface buckling, revealing quantitative selection rules that have not previously been reported for tri-layer structures. The results show that the tri-layer film/substrate structure exhibits two instability modes: film-intermediate co-buckling and film-only wrinkling. By simply varying the middle layer’s elastic modulus or its thickness, one can move the structure across the boundary that separates the film-only and bi-layer buckling regimes, providing a direct mechanical selection for on-demand mode. In addition, the wrinkle amplitude increases monotonically with the applied initial strain. Those findings offer a theoretical reference for designing flexible electronics based on film/substrate structures.
Chen, HaoZhang, WulinSong, Yahui
This study adopts a solvent-free in-situ molding process, using liquid ethylene-propylene-diene monomer (LEPDM) as the base rubber to prepare vacuum sealing materials. The effects of the blending ratio of EPDM/LEPDM on mechanical properties, processing characteristics, physical-mechanical properties, compression characteristics, and vacuum condensable volatiles were investigated. The influence of lamellar intercalated structural fillers on gas permeability was also examined. The results indicate that the addition of LEPDM significantly reduces the Mooney viscosity, improves filler dispersion, and achieves good processability. When the LEPDM blending amount exceeds 20 phr, significant changes occur in mechanical properties, compression modulus, and compression set, which are related to phase transformation. Vacuum pretreatment and vacuum condensable volatile test results show that the traditional plasticizer DOP exhibits high total mass loss (TML) and collected volatile condensable materials (CVCM). However, when LEPDM is partially used to replace EPDM at a blending ratio of 20 phr, TML ≤ 1% and CVCM ≤ 0.1% can be achieved. With the increase in organically modified montmorillonite (OMMT) content, the gas permeability coefficient first decreases and then increases. When the OMMT content is 15 phr, the material exhibits good gas barrier properties
Han, XiaoShi, LeiChen, ZongwenZhang, ZhaoyangCheng, Wei
This study presents a systematic investigation into the assembly stress and fatigue life of 60-series harmonic reducers. A sophisticated finite element simulation model is constructed to precisely simulate the real assembly process and calculate stress distribution in the flexspline under axial assembly errors. In addition, corresponding fatigue life tests are designed to explore the influence of different axial assembly errors on the number of rotation cycles and transmission efficiency of the harmonic reducer. By comparing the predictions of the fatigue life mathematical model with the test data, a reliable fatigue life prediction method is established, providing a solid theoretical basis for the whole-machine assembly process and reliability design of this series of harmonic reducers.
Du, YuefeiQiu, HaodongFan, YongLi, ZiyuanDong, YiZhang, ChiLi, ChenzhengLi, Yuan
Large-sized irregular castings are critical components extensively employed in large-scale equipment manufacturing. Due to their substantial dimensions and complex geometries, the assembly and docking processes between different components present significant challenges. To address the docking problem between large-scale irregular castings, this study proposes a casting docking method based on relative pose, along with a modeling approach for irregular castings, and accomplishes the docking process through the control of an industrial robot. Firstly, the current poses of feature points on the docking surfaces are measured. Based on these measurements, the relative pose transformation relationship between the center point of the docking surface and the robot’s Tool Center Point (TCP) is established, thereby constructing the docking model. This model calculates the relative deviation between the current pose and the theoretical pose. Subsequently, the robot motion is controlled according to this deviation to achieve precise docking. Finally, a simulation environment was built using KUKA. Sim Pro with Office Lite to simulate the docking process of large-sized irregular castings. The results demonstrate that the relative pose-based docking method effectively accomplishes the docking task. This study provides an effective solution for the docking of large-sized irregular castings.
Liu, HaoranJia, HailiWang, AiminXigang, FanPeidong, Su
This paper investigated the small deformation control of a large vertical vacuum vessel, a critical component in aerospace testing with stringent deformation limits under specific test conditions. Building on engineering experience and economic considerations, we designed oversized and multi-array external reinforcement rings tailored to the vessel’s spatial geometry to enhance its stiffness and stability. A novel integrated structural design was proposed, which mechanically couples the vacuum vessel with the concrete foundation via embedded components, specifically, by configuring optimized embedded parts at the vessel’s base and external reinforcement ring bottom, and then welding and binding these parts to the foundation’s embedded elements. This design significantly boosted the vertical vessel’s overall structural strength, rigidity, and stability. Ansys Workbench was used to simulate and analyze the vacuum vessel under different experimental conditions, and finite element simulations of the vessel under diverse experimental conditions validated that the integrated design achieves low stress and minimal deformation, compliant with test requirements. Post-installation deformation measurements further confirmed good agreement between experimental data and simulation results, verifying the model’s accuracy. The proposed fixed support structure addresses the limitations of traditional support systems for small-deformation applications and offers a new design paradigm for vertical vessel supports in high-precision engineering scenarios.
Bo, YangShizeng, LvXiao, HaoJie, Gong
This paper designs and synthesizes a series of high-performance waterborne polyurethane (WPU) laminating adhesives using polyester, polyether polyols and isophorone diisocyanate as the main raw materials. It focuses on exploring the effects of polyol types and R value (the ratio of polyol to isocyanate) on the properties of the adhesives, including emulsion viscosity, solid content, water absorption rate of the adhesive film, mechanical properties, and bonding performance on different substrates. The results show that WPU2 with polycarbonate diol (PCDL) as the polyol has the best water resistance and the highest tensile strength; WPU1 with polytetrahydrofuran (PTMG) as the polyol has the optimal elongation at break and exhibits outstanding bonding performance on the polar substrate PET; the regulation of R value can optimize the bonding performance of the adhesive on the non-polar substrate BOPP. This type of WPU laminating adhesive features low VOC emissions, no benzene-based solvents, excellent flexibility, and good resistance to high and low temperatures. It not only meets the environmental protection and safety requirements in packaging fields such as food and medicine, but also shows potential application value in high-end fields like aerospace interior compounding and lightweight transportation structure bonding. Its performance is highly compatible with the strict requirements for materials in the modern aerospace and transportation industries. The adjustable strong adhesiveness, compliance with strict emission standards, and adaptability to various substrates make it an ideal choice for a new generation of composite manufacturing, especially suitable for industrial fields pursuing reliability, sustainability and high performance.
Wang, ChengmingYu, JiachengWang, HuixiaHuang, YiqiangRen, Xiue
To enhance the service life of cemented carbide brazed circular saw blades used in sand willow stump cutting machines and to mitigate the problem of uneven stress distribution on saw teeth during cutting, this study investigates the circular saw blade as the research object. Sand willow, widely distributed in arid and desertification-prone regions of northern China, plays a vital role in ecological restoration and biomass utilization. However, due to the high density and toughness of its stems, conventional saw blades often experience severe tooth wear and premature failure, limiting the efficiency and stability of stump cutting operations. In this work, the dynamic simulation module of ABAQUS was employed to establish a finite element model of the cutting process. A Box–Behnken Design (BBD) combined with response surface methodology was then applied to systematically evaluate the influence of key tooth parameters on stress distribution. Using the maximum equivalent stress at critical nodes as the optimization criterion, a cooperative optimization strategy was developed to balance tooth strength and cutting efficiency. The optimized design markedly improved the mechanical performance of the saw teeth. Compared with conventional blades, the maximum stress value was reduced by 51%, resulting in enhanced reliability and prolonged service life. These findings demonstrate the feasibility of integrating finite element simulation with statistical optimization for tool design in forestry machinery, and provide both theoretical insights and practical support for advancing specialized sand willow cutting equipment, thereby contributing to ecological restoration and sustainable biomass utilization in desertification-affected regions.
Li, ZhongZhang, BinbinHan, YiliangHe, JinjunRen, YuyanYang, JianjunWang, HaichaoPei, Zhiyong
In this paper, PTFE membranes were used to preform delamination defects, and VARI technology was employed to prepare marine composite sandwich structures with such defects. The cohesive zone model was used to emulate the interfacial bonding characteristics, thereby establishing a simulation analysis model to assess the edgewise compressive behavior of marine composite sandwich structures with delamination discontinuities. By combining experimental data with simulation results, the edgewise compressive resistance of marine composite sandwich structures was evaluated. Additionally, various parameters including the size, depth, quantity, and geometry of the delamination defects were studied to investigate their effects on the edgewise compressive performance of the marine laminated structures. The research results indicate that as the number of delamination defects increases, the edgewise compressive strength of the sandwich structure gradually decreases. Particularly, when the diameter of the layering defect is less than 30 millimeters, the influence of the defect on the edgewise compressive strength of the sandwich structure can be negligible. Conversely, when the diameter of the defect exceeds 30 millimeters, the rate of decrease in edgewise compressive strength increases significantly with the increase in the diameter of the defect, thereby greatly exacerbating the adverse effects of the delamination defects and ultimately resulting in a 10.77% reduction in the edgewise compressive strength. Furthermore, it was observed that the delamination defects located at the interface between the two panels and the core material on both sides of the sandwich structure do not affect each other, and to a certain extent, improve the compressive stability of the specimen. The degree of edgewise compressive strength reduction caused by elliptical delamination defects with the same area and long axis length is less than that of corresponding circular delamination defects, indicating that using circular delamination defects in the analysis of composite material structures with delamination defects is safer.
Zhang, YaoXu, MingcaiBian, TianyaZhou, SongqiangJi, BingCheng, JiahuanZhuang, YaLi, Xiang
This study proposes a data-driven surrogate modeling framework for predicting solidification time and mold thermal stress during low-pressure die casting (LPDC) of aluminum alloy wheels. The methodology employed an optimal Latin hypercube design (OLHD) to sample key parameters including cooling channel geometry and process conditions. A sequential simulation methodology combining ProCAST and Abaqus was implemented to generate a comprehensive dataset of solidification times and thermal stress distributions. Based on this dataset, surrogate models were developed using Support Vector Regression, Kriging, and Polynomial Response Surface Methodology, with their hyperparameters automatically tuned through Bayesian Optimization (BO). The optimized models were rigorously evaluated using four statistical metrics: Coefficient of Determination (R2), Mean Squared Error (MSE), Mean Absolute Error (MAE), and Root Mean Squared Error (RMSE). The evaluation results show that the BO–SVR model demonstrated superior prediction accuracy for both output responses and exhibited exceptional nonlinear fitting capability. This work establishes an effective modeling approach for simultaneous quality and efficiency optimization in wheel manufacturing.
Fuhao, FanZhan, YunlangZhan, ZhenfeiYang, YutongXiao, YongHuang, Shiyao
Blended metal powders offer a compelling alternative to pre-alloyed powders in metal additive manufacturing by providing access to a wider range of alloy compositions and avoiding the high costs in producing pre-alloyed powders. In this work, a new and crack-free Ti-5AlMnScZrMgSiFe alloy (in wt.%) was manufactured by laser powder bed fusion (L-PBF) from mixed powders to investigate the microstructures, mechanical performance of printed parts. Ti-5 AlMnScZrMgSiFe alloy contains both alpha (α) and alpha prime (α′) phases. Further microstructural characterizations show that the L-PBF Ti-5 AlMnScZrMgSiFe contain dense dislocations and twins formed in additive manufacturing process. The as-printed Ti-5 AlMnScZrMgSiFe alloy exhibits a tensile fracture strength of ~950 MPa with a fracture elongation of ~12.5%. The eye-catching properties are attributed to the dense dislocations, nano-twins and solid-solution strengthening.
Feng, ShuaiGuan, ShuaiKong, HaohaoSun, YingxiangSong, YoupengHou, YaqingBi, ZhongnanZhang, Shaoming
Collaborative manufacturing networks enhance production efficiency but are increasingly vulnerable to cascading failures due to their complex interdependencies, particularly in critical processes like gear manufacturing. This study addresses this challenge by proposing a dynamic modelling framework based on Cellular Automata. Utilizing manufacturing resource and task scheduling data, a material flow-driven Directed Acyclic Graph (DAG) is constructed to capture the network’s hierarchical topology. Key innovations include state transition rules with memory effects, where dynamic failure probability integrates neighbouring node states and historical failure records, governing normal node failure, recovery, and re-failure (with an attenuation factor reflecting enhanced resilience). The case study focusing on the gear manufacturing industry, through simulations on a 100-node gear production network, reveals spatiotemporal failure propagation patterns. By implementing resource redundancy configuration and material flow optimization, iterations generally converge around 35 steps, demonstrating significant self-recovery potential and strong network robustness in collaborative manufacturing networks. This approach provides a scientifically grounded tool for identifying cascading risks in collaborative manufacturing networks.
Bai, HaoKou, ZhidaLiang, JingyaZhang, Cheng
Under China’s intelligent manufacturing strategy, manufacturing enterprises are expected to achieve digital and networked operations by 2025, with full digital transformation by 2030. Intelligent factories, the core of this transformation, rely on interconnected, integrated, and data-fused systems. This paper focuses on the micro-assembly intelligent workshop at the Nanjing Research Institute of Electronics Technology, which produces micro-circuit modules for large-scale complex electronic systems. The workshop combines discrete and process manufacturing modes, presenting unique challenges for digital management. A digital management platform based on a five-layer architecture (device, network, data, application, and decision layers) is proposed to address multi-dimensional business needs, including production scheduling, logistics, execution, and decision optimization. A hierarchical workflow structure of the workshop, consisting of a main workflow and several sub-processes, is in-depth studied and designed. The platform is constructed based on requirements analysis and workflow design of the workshop and integrates systems such as MES, APS, WMS, and SCADA, supported by AI-driven big data analytics. This study offers a practical framework for advancing digital transformation in the electronics industry.
Zhang, JianWang, JiafengGuo, Yongzhao
During the cutting process of low-stiffness structural components, the coupling effect between dynamic deformation and cutting forces presents a significant challenge in accurately predicting machining-induced deformations, thereby complicating quality control in the manufacturing of such parts. To address this issue, a cutting force-structural coupling simulation method that combines experiment and finite element is proposed, which takes into account the low-stiffness characteristics of structural components. Focusing on thin-plate parts as the research object, an orthogonal experimental scheme is designed considering workpiece thickness that serves as an indicator of rigidity. A milling force prediction model correlated with workpiece thickness is established. Based on the predicted cutting forces, a multi-analysis-step simulation method is introduced to analyze the machining deformation of structural parts. Additionally, a theoretical analytical model for the machining deformation of thin-plate workpieces is developed. A comparison between the theoretical and simulation results shows a relative error of less than 1.03%, validating the accuracy of the proposed simulation method. Finally, the exponential regression model for the machining deformation is constructed using training data obtained from the simulations. The prediction error of the regression model is less than 15%. The findings of this study are also applicable to predicting machining deformations in other large and low-stiffness structural components.
Zhao, YongshengGao, PengfeiXu, JingjingLiu, Zhifeng
Laser directed energy deposition (LDED) is widely used in various fields due to its fine forming structure and superior performance. However, the characteristics of the hot forming process result in significant residual tensile stress in the formed materials, which affects the capability and useful life of the mechanism accessory. The hybrid manufacturing technology of shot peening (SP) and LDED has a significant influence on the elimination of defects and the improvement in microstructure of formed materials and reducing residual stress, but it also has limitations. To solve the problems, such as the introduction of powders and the difficulty in recycling and classification when using heterogeneous materials for shot peening in hybrid processes, this paper proposes a method of strengthening with the same material, establishes a thermal shot peening simulation model for the hybrid process, and conducts experimental verification. The research finds that the average generated stress of SP in hybrid manufacturing technology is -215.6 MPa, and the thickness of the strengthening layer is about 40 μm. The subsequent hot forming process will eliminate part of the induced stress by SP on the previous deposition, but the deposited stress on the surface is reduced compared with that in the single process. The hybrid manufacturing technology of SP and LDED, based on the same material, effectively utilizes the residual heat from the forming process, providing feasibility for engineering applications.
Zhang, XiaoyuZhang, MinLi, DichenJiang, YunfengChen, XinjinFei, YaHu, YingLiu, Yuyang
This study carefully designed and successfully developed a mechanical voltage stabilizing control device. The device uses silicone oil as the key component material of the liquid spring and 1Cr13 as the main material of the pressure control unit, enhancing its high-pressure resistance (up to 35 MPa), oxidation resistance, and acid-alkali corrosion resistance. By optimizing the transmission mechanism and simplifying the pressure regulation module, the device achieves a pressure regulation range of 0.1–21 MPa with an accuracy of ±0.01 MPa, significantly broader and more precise than traditional devices. To address manufacturing challenges, advanced CNC machine tools, ceramic cutting tools, and optimized heat treatment processes (e.g., quenching and tempering) were adopted, ensuring component machining accuracy within ±0.02 mm. Field applications in 13 oil wells demonstrated a 15.6% increase in daily oil production (from 25.5 t/d to 29.5 t/d) and a 17.9% increase in daily gas production (from 2800 m^3/d to 3300 m^3/d), with stable casing pressure control at 5.3 MPa. The device has created 1.225 million yuan in economic benefits while eliminating safety hazards, providing critical technical support for efficient and environmentally friendly oil and gas production.
Wang, GangLiu, CuicuiTong, DeshuiCao, JianMu, TaijiHan, Baidong
In this paper, 6061-T6 aluminum alloys were subjected to high-speed friction stir welding. The associated weld formation, microstructure, and mechanical properties were systematically examined via combined experimental observation and numerical simulation approaches. At a welding speed of 3000 mm/min and a rotation rate of 3800 rpm, the defect-free weld was simply achieved due to the simultaneous intense thermal input and enhanced material flow. Microstructural analysis further demonstrated a fine equiaxed grain structure featuring a predominant simple shear texture with A/A components. The resultant joint exhibited an ultimate tensile strength equivalent to 80% of the base material, accompanied by excellent fracture elongation. This research provides experimental evidence for designing high-efficiency and high-quality bonding processes for aluminum alloys.
Guan, YuankaiWang, RuiyangZhang, KexinLin, ZhichengDeng, JunLiu, ZheGanushchak, OlegVoitenko, OleksandrZhao, YunqiangGao, Shiyi
In this paper, the simulation software was used to conduct a thermal analysis of the design scheme of a certain type of forced air-cooled display and control console, and the results were compared with the experimental results. The results show that in an environment of 50 °C, the maximum temperature of the chip on this strong display control console does not exceed 98 °C, meeting the usage requirements of the chip and the thermal reliability requirements of the display control console. The thermal design scheme of the display and control console proposed in this paper has the advantages of a simple structural form, good heat dissipation effect, low fan noise, and consideration of the heat dissipation of multiple heat sources. It can provide a good reference for the thermal design of similar display and control consoles.
Li, Yun
Laser welding technology for aluminum alloy electrode and busbar connections: addressing challenges in battery module assembly. In this work, a CFD framework was built in ANSYS Fluent using a Gaussian rotating heat-source representation, while a VOF approach was used to capture the transient gas–liquid interface in deep-penetration welding. A three-dimensional, transient, thermal-fluid coupled numerical model of the dual-layer heterogeneous aluminum alloy laser deep penetration weld pool was established concurrently with laser deep penetration welding experiments. Results indicate: Peak flow velocities in the weld pool during welding are concentrated along the weld centerline, with flow vectors predominantly directed axially along the weld. Once a quasi-steady keyhole regime is established, vaporization-induced recoil pressure becomes the primary driver governing melt circulation. The liquid metal first impinges on the pool bottom along the keyhole wall and then recirculates upward near the pool boundary, producing strong vortical motion. These findings are intended to support parameter selection and process optimization for laser welding of layered dissimilar aluminum components used in battery tab–busbar assemblies.
Lv, WenjunWu, Yan
This study aims to verify the accuracy and stability of a system used for measuring and analyzing the welding deformation of vehicle bodies under different welding parameters. A 3D laser scanner was employed to capture the surface topography data of the vehicle’s front deck before and after welding. In order to determine the welding deformation, PolyWorks software was utilized for deformation analysis, which processed the 3D scanning data and compared the post-welding data set. A dedicated vehicle body welding deformation measurement system was developed, including hardware configuration and software development. The BP neural network algorithm was adopted to predict the welding deformation, and the results indicated that the deviation between the predicted values and the average experimental measurements was less than 10%. This confirmed the practicality of the BP neural network in predicting welding deformation and highlighted its effectiveness in technical support for the optimization of welding parameters and deformation control in automotive manufacturing.
Li, LinaZhang, YiqiSun, HongchangWei, Xiezhen
High-precision five-axis machining puts forward strict requirements for the stiffness and position stability of the AC double-angle milling head, especially when the gear transmission system is used under heavy cutting load and complex force coupling conditions. In the actual processing environment, the non-uniform deformation caused by structural coupling and load changes will directly affect the machining accuracy and stability. In order to solve these problems, this paper designs and analyzes a gear-type AC double-angle milling head with a pendulum structure and a layered modular structure. A parametric finite element model was established, and ABAQUS software was used to conduct a static analysis of two typical A-axis directions (0° and 90°), taking into account the internal prestressing force generated by gravity, cutting force, and gear meshing to reflect the typical working conditions. Under the same boundary conditions and load conditions, the influence of different structural materials on the overall stiffness was further studied through comparative analysis. The results show that under the conditions of five-axis linkage machining and positioning machining, the overall deformation of the milling head is maintained within the micron range, which meets the requirements of high-precision machining. The deformation behavior shows obvious dependence on the A-axis direction, reflecting the inherent anisotropic stiffness characteristics of the structure. Compared with the traditional structure, the proposed design has better rigidity performance under combined load conditions and provides practical reference values for the subsequent structural optimization, material selection, and precision control of high-performance five-axis CNC milling heads.
Xie, XinguiYuan, YongchaoQi, QuanLi, Xiangshuai
As a key structural component of scroll compressors, the forming quality of the scroll plate directly affects overall performance. To address the issues of high forming load and poor rib filling in conventional processes, this study investigates the semisolid closed-die forging of 6061 aluminum alloy through numerical simulation. Semisolid rheological data were obtained from high-temperature compression tests. We also formulated an Arrhenius-type constitutive model to predict material behavior. This model proved highly reliable, achieving a correlation coefficient of 0.99547 and keeping the average absolute relative error down to 3.67%. By employing both orthogonal experiments and simulations, we evaluated how different process parameters impacted the outcome. This analysis ultimately yielded an optimal parameter combination: a die temperature of 350°C, a billet temperature of 600°C, and a punch velocity of 10mm/s. Under these conditions, the forming load, flow behavior, stress–strain distribution, and temperature evolution were analyzed. The results show complete rib filling, uniform deformation, and absence of defects, providing theoretical guidance for industrial applications of semisolid closed-die forging of scroll plates.
Xiong, LinhuaZhang, MengjiaoChang, MingLiu, BoyangWang, YongfeiZhao, Shengdun
Aiming at the problems of seed cane pile-up and unstable seed supply efficiency in the sugarcane seed production line caused by the seed supply device, a stable seed supply control system was designed, which consists of a seed collection box, an elastic seed-clearing plate and an electrical control system, etc. The EDEM-RecurDyn coupling simulation was adopted to analyze the seed supply process, and the optimal elastic seed-clearing plate structure was designed. Using the single factor test and Box–Behnken experimental design analyzed the effects of the seed supply belt speed, the speed of the first conveyor belt, the number of sugarcane seeds in the collection box and the seed cutting efficiency on the supply efficiency. Establish a quadratic regression model for the efficiency of seed supply and determine the optimal parameter combination: the seed supply belt speed of 0.097 m/s, first conveyor belt speed of 1.639 m/s, and the number of sugarcane seeds is 14. Using the number of sugarcane seeds as the input quantity for the controller, the real-time data is fed back by the TOF sensor. The controller automatically adjusts the seed-cutting efficiency to maintain the continuity and stability of the seed supply process of the seed supply device. The test results show that after applying this system, the seed supply efficiency reached 1.77 setts/s, which was 6% higher than that of the fixed-parameter system. This research can provide technical support for the stable seed supply of integrated equipment for sugarcane seed production.
Li, ShangpingXu, HechangOuyang, RunhongLi, Kaihua
Addressing the performance degradation bottleneck of conventional impact-resistant materials under complex operating conditions, and the limitation of existing research focusing primarily on enhancing single properties while neglecting material equilibrium, this study employs silicon carbide whiskers (SiCw) as the reinforcing phase. Through surface modification techniques, SiCw/celluloid and SiCw/polyimide dual-polymer composite systems were constructed and systematically investigated. Surface modification of SiCw was achieved using titanate and silane coupling agents. Through mechanical testing and X-ray photoelectron spectroscopy (XPS) characterisation, the effects of SiCw loading and modification treatments on composite mechanical properties and interfacial bonding were analysed. Results indicate that SiCw introduction significantly enhances the tensile, flexural, and impact strength of the polymer matrix, with optimal addition ratios identified: 6% for the celluloid system and 1.0% for the polyimide system. Surface modification further optimises toughening effects by reducing surface oxide layers and impurities on SiCw particles while strengthening interfacial bonding. This study provides practical guidance for the system design of high-performance impact-resistant composites. The resulting materials hold broad application prospects in sectors demanding high structural impact resistance, such as aerospace and transportation.
Xue, KaimingHu, Haobang
Addressing the challenge of high-precision control requirements for assembly force and displacement during the automatic assembly of digital direct-writing light source lens units, this paper proposes an automatic assembly system design based on impedance control. The system employs torque motors as actuators and achieves dynamic, precise regulation of assembly force and displacement through impedance control with force-displacement coupling. The simulation process consists of three parts: finite element simulation of the assembly system structure, finite element simulation of the assembly process, and MATLAB simulation of impedance control. The finite element simulation of the assembly system structure verifies structural strength and determines deformation values for assembly displacement compensation. A finite element simulation of the assembly process is utilized to investigate the coupling relationship between assembly force and displacement, yielding the coupled force-displacement curves during assembly and determining the theoretical maximum assembly force. The MATLAB simulation of impedance control analyzes parameter settings, including three parameters: theoretical mass, theoretical damping, and theoretical stiffness, in order to ensure the controlled output converges to theoretical values. The main innovation lies in incorporating theoretical maximum assembly force and displacement as impedance control inputs, enabling the force-displacement curve to converge to the theoretical curve, thereby improving assembly quality and precision. The experimental results demonstrate significant improvements in system stability, response speed, and assembly force control precision, effectively enhancing the assembly accuracy and overall efficiency of automated light source production lines. This research provides a viable solution for high-precision assembly of digital direct-writing light source lens units in intelligent manufacturing environments.
Li, FuduanWang, HuaWang, RixinZhang, Xianmin
Metal fins with complex structural surfaces play a crucial role in cooling highly heat-intensive electronic products, and a facile method for fabricating such metal fins is urgently needed. Herein, a simple machining method was proposed for fabricating metal fins with novel waveform structures. The new machining method combined plowing extrusion and cutting (PE-C) processes, enabling one-step fabrication of wavy fins, exhibiting excellent flexibility and efficiency. The combined PE-C tool was first designed and manufactured. Subsequently, experiments for fabricating wavy fins were developed and conducted. Based on this, an in-depth analysis of forming procedures was performed using in-situ experimental insights. Moreover, forming characteristics of wavy fins under key parameters (e.g., the tool rake angle γ^c and the cutting velocity V^c) were discussed. Results show that the novel wavy fins were successfully manufactured by the proposed PE-C method. Wavy fins exhibited excellent, well-developed surfaces with a complete corrugation structure, and their geometric dimensions could be adjusted through processing parameters. The new PE-C method utilized two consecutive stages (i.e., the PE and cutting stages) to achieve the fabrication of wavy fins. The PE stage shaped the uncut metal surface into grooved structures, while the cutting stage transformed the groove structure into a waveform structure. Multiple folding principles, rather than conventional shear deformation, were utilized to achieve wavy fins. Reducing the γ^c and V^c would contribute to obtaining fins with the larger waveform structures. PE-C exhibited excellent potential in the field of heat exchange metal fin manufacturing.
Zhang, BaoyuLiu, ShudengYe, Zhitong
This study systematically discussed the high-temperature flow behavior of the Mg-Al-Zn based AZ91 alloy, which has significant application potential in modern aviation and automotive industries. The study was carried out in the temperature range of 250°C-450°C and the strain rate range of 0.001 s^−1 -0.1 s^−1, which met the typical industrial hot processing environment. The analysis of high-temperature flow behavior shows that the flow stress is inversely proportional to the deformation temperature and is proportional to the strain rate. An important finding is that the constitutive model parameters are significantly sensitive to strain, so the strain-compensated Arrhenius constitutive model is developed. The model shows high accuracy in predicting the thermal flow stress of AZ91, and provides a valuable calculation tool for the simulation and optimization of forming processes in aerospace parts manufacturing. The results show that the extruded original microstructure presents slender fine grains, while the deformed sample shows a temperature dependent transformation: the low-temperature bimodal structure evolves into uniform fine grains at intermediate temperature, and the grains begin to coarsen at high temperature. At constant high temperature, low strain rate promotes grain growth and twin formation, while high strain rate refines grains and inhibits twins, and dislocation slip is the dominant deformation mechanism. These findings provide vital guidance and support for optimizing hot working parameters of AZ91, and are particularly important for manufacturing lightweight components in aircraft structures and automotive systems. The established process performance relationship is helpful to develop energy-saving manufacturing strategies for transportation equipment, and supports the goal of reducing weight and improving performance in the industrial field.
Li, JusenChang, MingZhu, WenyuSun, HaoranChen, KaidaYang, XiaoyinZheng, ZhenhaoZhao, Shengdun
The extreme cold environment has a significant impact on the mechanical properties of welded hollow ball nodes, which are crucial components in large-span steel structures. In this paper, based on the comprehensive test data of drum-shaped welded hollow sphere nodes from Beijing Daxing International Airport, a sophisticated finite element model incorporating welding residual stress is established. Through detailed static loading analysis and systematic hysteresis performance studies, the research thoroughly explores the influence mechanisms of low temperature on node bearing capacity, deformation capability, and energy dissipation performance. The investigation reveals that while the bearing capacity of the nodes increases significantly in low-temperature environments, both their plastic deformation capacity and energy consumption performance are notably reduced. These findings provide valuable theoretical references for the design and optimization of large-span mesh frame structures in cold regions, enabling engineers to better account for temperature effects in structural calculations and safety assessments. The results have important implications for improving the reliability and durability of steel structures in extreme cold environments.
Luo, YanzhiJin, Changming
This paper introduces the electroplastic effect into the sheet metal incremental forming process, using 2A12 aluminum alloy as the research material. An orthogonal experiment was designed, and the results were analyzed using range analysis and matrix analysis methods. The influence of electric current, frequency, and traditional incremental forming parameters on the forming accuracy of 2A12 aluminum alloy sheets was investigated. The results show that the introduction of pulse current can improve the forming accuracy of 2A12 aluminum alloy sheet. And within a certain range, as the electric current increases, the geometry accuracy of the part is significantly improved. Based on two accuracy indicators—average springback amount and springback angle, a comprehensive analysis determined that the optimal forming parameters are electric current 375 A, feed rate 600 mm/min, step size 0.6 mm, tool diameter 12 mm, and current frequency 400 Hz.
Pan, FeiZhao, QuanguangHuang, XuFang, Jinxiu
Advanced composite materials have garnered widespread attention in the aerospace and other fields with stringent weight requirements, owing to their superior properties, such as lightweight, high strength, high modulus, and corrosion resistance. Compared with traditional metal materials, advanced composite materials can reduce structural weight by 30%. Lattice structures possess unique characteristics, including high designability, low cost, and high damage tolerance. As a specialized reinforced structure, they have been identified as one of the key structural configurations for next-generation aircraft. Composite lattice structures, which integrate the advantages of composite materials and lattice architectures, provide an ideal structural material for achieving lightweight and multifunctional aerospace equipment. However, due to the intricate geometries and diverse functional design requirements of lattice structures, the fabrication of these structures presents significant challenges, and there is an increasing amount of research on improving the accuracy and performance of composite lattice structures. The expandable mold process represents an approach for manufacturing composite lattice structures, where pneumatic pressure from rubber expansion enables consolidation of the lattice assembly during elevated-temperature curing to achieve the finished composite part. This study reviews composite lattice structures, verifies the feasibility of using rubber as an expansion mold by investigating the thermal stability and expansion properties, and then prepares composite lattice structures via the expandable mold technique. Additionally, composite lattice structures are prepared using laminated machining, an interlocking process, and a 3D printing process. The advantages and disadvantages of different process methods for forming composite lattice structures are compared, and finally, the future trends in high-performance lattice development are discussed.
Han, ShuhaoLv, ZhenMa, ChengXiu, ZhifengSong, Yanhua
To obtain additional space for industrial sorting and assembly line labeling operations, this study conducts an analysis of the four-bar mechanism. Based on this analysis and combination, the redundant parallel mechanism is introduced. That is, on the basis of the traditional parallel mechanism with central rotation, the objective of expanding the working space is achieved. The degree of freedom of the screw theory and the disparities between the working space of this mechanism and that of the traditional mechanism are analyzed. Finally, through application analysis, it is demonstrated that the working space of this mechanism is variable and that the mechanism can adapt to diverse workplaces.
Li, WenqianZhang, Xiaojie
Two sets of X80 pipes with a diameter of 1219 mm × 27.5 mm were welded using a fully automatic welding process (GMAW) and a combined automatic welding process (GTAW + FCAW-G), respectively. By analyzing the microstructure, strength, impact toughness, and fracture toughness of welded joints, the differences in microstructure and properties of circumferential weld joints under different automatic welding processes were studied. The results showed that the design of multi-layer and multi-pass welding and appropriate heat input controlled the microstructure of the weld seam and heat-affected zone area of the circumferential weld joint. Both automatic welding processes obtained welded joints with finer microstructure, thereby ensuring the strength and toughness of the joint. The tensile strength and yield strength of the welded joints under two automatic welding processes reach over 680 MPa and 600 MPa, respectively. The welded joints under both automatic welding processes have good impact toughness and fracture toughness at - 10 °C, with a ductile-brittle transition temperature below -50 °C and crack tip opening displacement (CTOD) values greater than 0.254 mm. The tensile strength, yield strength, impact toughness, and fracture toughness of the fully automatic welding ring weld joint are better than those of the combined automatic welding.
Liu, JianNiu, HuliWang, HongSun, XinyanYang, HuaqingBai, Qian
This specification covers a corrosion- and heat-resistant cobalt alloy in the form of bars, forgings, flash-welded rings, and stock for forging or flash-welded rings.
AMS F Corrosion and Heat Resistant Alloys Committee
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