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26 pages, 8400 KiB  
Article
Conceptual Design of a Hybrid Composite to Metal Joint for Naval Vessels Applications
by Man Chi Cheung, Nenad Djordjevic, Chris Worrall, Rade Vignjevic, Mihalis Kazilas and Kevin Hughes
Materials 2025, 18(15), 3512; https://doi.org/10.3390/ma18153512 - 26 Jul 2025
Viewed by 324
Abstract
This paper describes the development of a new hybrid composite for the metal joints of aluminium and glass fibre composite adherents. The aluminium adherend is manufactured using friction stir-formed studs that are inserted into the composite adherend in the through-thickness direction during the [...] Read more.
This paper describes the development of a new hybrid composite for the metal joints of aluminium and glass fibre composite adherents. The aluminium adherend is manufactured using friction stir-formed studs that are inserted into the composite adherend in the through-thickness direction during the composite manufacturing process, where the dry fibres are displaced to accommodate the studs before the resin infusion process. The materials used were AA6082-T6 aluminium and plain-woven E-glass fabric reinforced epoxy, with primary applications in naval vessels. This joining approach offers a cost-effective solution that does not require complicated onsite welding. The joint design was developed based on a simulation test program with finite element analysis, followed by experimental characterisation and validation. The design solution was analysed in terms of the force displacement response, sequence of load transfer, and characterisation of the joint failure modes. Full article
(This article belongs to the Section Advanced Composites)
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13 pages, 5197 KiB  
Article
Evaluation of Ballasted Railway Track Response in Potentially Critical Areas Using Vibration Measurements
by Mojmir Uranjek and Andrej Štrukelj
Sensors 2025, 25(14), 4363; https://doi.org/10.3390/s25144363 - 12 Jul 2025
Viewed by 294
Abstract
In railway infrastructure, particularly where concrete sleepers are employed, certain critical zones exhibit pronounced degradation of the ballast layer. Previous studies have identified several contributing factors, including the presence of welds, heterogeneity in the substructure beneath the sleepers, and variations in the track’s [...] Read more.
In railway infrastructure, particularly where concrete sleepers are employed, certain critical zones exhibit pronounced degradation of the ballast layer. Previous studies have identified several contributing factors, including the presence of welds, heterogeneity in the substructure beneath the sleepers, and variations in the track’s geometric parameters. Of these factors, the presence of welds seems to have the most significant influence. This article aims to determine whether differences in the ballast railway track’s response to traffic loads at weld locations can be identified in the initial phase, before obvious damage appears. Vibration responses in terms of displacement, velocity, and acceleration were measured on upgraded concrete sleepers equipped with rubber under-sleeper pads. The results indicate that velocities and accelerations at rail weld locations differ significantly from those in adjacent track sections, when the railway track is in an intact, undamaged condition. These results suggest a high likelihood of damage formation in these critical locations, indicating the necessity of preventive measures to mitigate damage. Possible mitigation measures that could help reduce the formation of damage are proposed. Full article
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15 pages, 16118 KiB  
Article
Axial Tensile Experiment of the Lap-Type Asymmetric K-Shaped Square Tubular Joints with Built-In Stiffeners
by Zhihua Zhong, Peiyu Peng, Zheweng Zhu, Xiang Ao, Shiwei Xiong, Jinkun Huang, Lihong Zhou and Xiaochuan Bai
Buildings 2025, 15(10), 1634; https://doi.org/10.3390/buildings15101634 - 13 May 2025
Viewed by 322
Abstract
To study the mechanical properties of asymmetric K-shaped square tubular joints with built-in stiffening rib lap joints, axial tensile tests were carried out on one K-shaped joint without built-in stiffening ribs and four K-shaped joints with built-in stiffening ribs using an electro-hydraulic servo [...] Read more.
To study the mechanical properties of asymmetric K-shaped square tubular joints with built-in stiffening rib lap joints, axial tensile tests were carried out on one K-shaped joint without built-in stiffening ribs and four K-shaped joints with built-in stiffening ribs using an electro-hydraulic servo structural testing system. The effects of the addition of stiffening ribs and the welding method of the stiffening ribs on the mechanical properties were studied comparatively. The failure mode of the K-shaped joint was obtained, and the strain distribution and peak displacement reaction force in the nodal region were analyzed. A finite element analysis of the K-shaped joint was carried out, and the finite element results were compared with the experimental results. The results showed that the addition of transverse reinforcement ribs and more complete welds shared the squeezing effect of the brace on the chord. Arranging more reinforcing ribs in the fittings makes the chord more uniformly stressed and absorbs more energy while increasing the flexural load capacity of the fittings’ side plates. The presence of a weld gives a short-lived temperature increase in the area around the crack, and the buckling of the structure causes the surface temperature in the buckling area to continue to increase for some time. The temperature change successfully localized where the structure was deforming and creating cracks. The addition of the reinforcing ribs resulted in a change in the deformation pattern of the model, and the difference occurred because the flexural capacity of the brace with the added reinforcing ribs was greater than that of the side plate buckling. Full article
(This article belongs to the Special Issue Application of Experiment and Simulation Techniques in Engineering)
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14 pages, 10083 KiB  
Article
Characteristics of Separations in Fracture After Crack Tip Opening Displacement Tests of Low-Carbon Microalloyed Offshore Steel S460MLO
by Eugene Goli-Oglu, Marco Palombo and Andrei Filatov
Alloys 2025, 4(2), 6; https://doi.org/10.3390/alloys4020006 - 23 Apr 2025
Viewed by 731
Abstract
Using the results from testing industrial batches of 23 mm steel heavy plates after thermomechanical rolling and subsequent post-weld heat treatment, the patterns of fatigue crack formation in the fracture specimens during CTOD (Crack Tip Opening Displacement) testing for fracture toughness are investigated. [...] Read more.
Using the results from testing industrial batches of 23 mm steel heavy plates after thermomechanical rolling and subsequent post-weld heat treatment, the patterns of fatigue crack formation in the fracture specimens during CTOD (Crack Tip Opening Displacement) testing for fracture toughness are investigated. Visual, microstructural, and fractographic studies of the nature of fracture formation and the surface of the secondary separations have been conducted. The probable causes of the manifestation of the potential “pop-in” effect on the load–displacement diagrams of the notch opening displacement are described, as well as its potentially negative impact on the interpretation of test results. Full article
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29 pages, 20381 KiB  
Article
A Study on the Force/Position Hybrid Control Strategy for Eight-Axis Robotic Friction Stir Welding
by Wenjun Yan and Yue Yu
Metals 2025, 15(4), 442; https://doi.org/10.3390/met15040442 - 16 Apr 2025
Viewed by 756
Abstract
In aerospace and new-energy vehicle manufacturing, there is an increasing demand for the high-quality joining of large, curved aluminum alloy structures. This study presents a robotic friction stir welding (RFSW) system employing a force/position hybrid control. An eight-axis linkage platform integrates an electric [...] Read more.
In aerospace and new-energy vehicle manufacturing, there is an increasing demand for the high-quality joining of large, curved aluminum alloy structures. This study presents a robotic friction stir welding (RFSW) system employing a force/position hybrid control. An eight-axis linkage platform integrates an electric spindle, multidimensional force sensors, and a laser displacement sensor, ensuring trajectory coordination between the robot and the positioner. By combining long-range constant displacement with small-range constant pressure—supplemented by an adaptive transition algorithm—the system regulates the axial stirring depth and downward force. The experimental results confirm that this approach effectively compensates for robotic flexibility, keeping weld depth and pressure deviations within 5%, significantly improving seam quality. Further welding verification was performed on typical curved panels for aerospace applications, and the results demonstrated strong adaptability under high-load, multi-DOF conditions, without crack formation. This research could advance the field toward more robust, automated, and adaptive RFSW solutions for aerospace, automotive, and other high-end manufacturing applications. Full article
(This article belongs to the Section Welding and Joining)
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19 pages, 12239 KiB  
Article
Research and Parameter Analysis of Lateral Resistance Performance of Assembled Corrugated Steel Plate Shear Wall
by Jianian He, Zheng Chen, Dongzhuo Zhao and Shizhe Chen
Appl. Sci. 2025, 15(8), 4369; https://doi.org/10.3390/app15084369 - 15 Apr 2025
Viewed by 386
Abstract
Corrugated steel plate shear walls (CSPSWs) exhibit excellent energy dissipation capacity and lateral resistance performance due to their unique “accordion structure”, making them a highly promising seismic component in prefabricated buildings. The assembled CSPSWs utilize bolted connections on both sides, which align with [...] Read more.
Corrugated steel plate shear walls (CSPSWs) exhibit excellent energy dissipation capacity and lateral resistance performance due to their unique “accordion structure”, making them a highly promising seismic component in prefabricated buildings. The assembled CSPSWs utilize bolted connections on both sides, which align with the energy-saving and emission-reduction trends of prefabricated construction. Compared to traditional welded connections, this method reduces the impact on frame columns during seismic deformation and allows for easier post-damage replacement. Through experimental and finite element analysis, this study systematically investigates the lateral mechanical behavior of assembled CSPSWs and compares them with flat steel plate shear walls (FSPSWs), revealing the stress mechanisms and failure modes of corrugated structures. Additionally, parametric analysis quantifies the influence of plate thickness, width/height ratio, and wave height on structural performance. Experimental results demonstrate that CSPSWs significantly outperform FSPSWs in out-of-plane displacement resistance and energy dissipation efficiency. Parametric analysis indicates that increasing plate thickness and width/height ratio enhances energy dissipation, while increasing wave height negatively affects energy dissipation capacity. This research provides theoretical support for the optimal design and engineering application of assembled corrugated steel plate shear walls. Full article
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22 pages, 7805 KiB  
Article
Seismic Performance of a Novel Precast Shear Wall with Mixed Wet and Dry Steel Plate–Bolt Connections: A Finite Element Study
by Qiang Du, Zhaoxi Ma, Yiyun Zhu, Geng Chen and Yue Zhao
Mathematics 2025, 13(7), 1168; https://doi.org/10.3390/math13071168 - 2 Apr 2025
Viewed by 488
Abstract
This paper proposes a hybrid steel plate–bolt dry and wet jointing method, where the dry jointing part is a steel plate–bolt connector joint and the wet jointing part is a cast-in-place concrete. The novel precast concrete shear wall (PCW) combines the advantages of [...] Read more.
This paper proposes a hybrid steel plate–bolt dry and wet jointing method, where the dry jointing part is a steel plate–bolt connector joint and the wet jointing part is a cast-in-place concrete. The novel precast concrete shear wall (PCW) combines the advantages of both dry and wet connections. A steel plate–bolt dry–wet hybrid connection shear wall model was developed using the finite element method, and a low circumferential reciprocating load was applied to the PCW. By analyzing the force and deformation characteristics of the wall, the results showed that the failure mode of novel PCWs was bending-shear failure. Compared to the concrete wall (CW), the yield load, peak load, and ductile displacement coefficient were 6.55%, 7.56%, and 21.49% higher, respectively, demonstrating excellent seismic performance. By extending the wall parameters, it was found that the increased strength of the novel PCW concrete slightly improved the load-bearing capacity, and the ductility coefficient was greatly reduced. As the axial compression ratio increased from 0.3 to 0.4, the wall ductility decreased by 22.85%. Increasing the reinforcement rate of edge-concealed columns resulted in a severe reduction in ultimate displacement and ductility. By extending the connector parameters, it was found that there was an increased number of steel joints, a severe reduction in ductility, enlarged distribution spacing, weld hole plugging and bolt yielding, reduced anchorage performance, and weakening of the steel plate section, which reduced the load-bearing capacity and initial stiffness of the wall, with little effect on ductility. Full article
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26 pages, 7700 KiB  
Article
Assessment of Structural Integrity Through On-Site Decision-Making Analysis for a Jacket-Type Offshore Platform
by Rodrigo Daniel Álvarez Bello Martínez, Juan Antonio Álvarez-Arellano and Youness El Hamzaoui
Appl. Sci. 2025, 15(7), 3418; https://doi.org/10.3390/app15073418 - 21 Mar 2025
Viewed by 1349
Abstract
This paper presents a comprehensive on-site decision-making framework for assessing the structural integrity of a jacket-type offshore platform in the Gulf of Mexico, installed at a water depth of 50 m. Six critical analyses—(i) static operation and storm, (ii) dynamic storm, (iii) strength-level [...] Read more.
This paper presents a comprehensive on-site decision-making framework for assessing the structural integrity of a jacket-type offshore platform in the Gulf of Mexico, installed at a water depth of 50 m. Six critical analyses—(i) static operation and storm, (ii) dynamic storm, (iii) strength-level seismic, (iv) seismic ductility (pushover), (v) maximum wave resistance (pushover), and (vi) spectral fatigue—are performed using SACS V16 software to capture both linear and nonlinear interactions among the soil, piles, and superstructure. The environmental conditions include multi-directional wind, waves, currents, and seismic loads. In the static linear analyses (i, ii, and iii), the overall results confirm that the unity checks (UCs) for structural members, tubular joints, and piles remain below allowable thresholds (UC < 1.0), thus meeting API RP 2A-WSD, AISC, IMCA, and Pemex P.2.0130.01-2015 standards for different load demands. However, these three analyses also show hydrostatic collapse due to water pressure on submerged elements, which is mitigated by installing stiffening rings in the tubular components. The dynamic analyses (ii and iii) reveal how generalized mass and mass participation factors influence structural behavior by generating various vibration modes with different periods. They also include a load comparison under different damping values, selecting the most unfavorable scenario. The nonlinear analyses (iv and v) provide collapse factors (Cr = 8.53 and RSR = 2.68) that exceed the minimum requirements; these analyses pinpoint the onset of plasticization in specific elements, identify their collapse mechanism, and illustrate corresponding load–displacement curves. Finally, spectral fatigue assessments indicate that most tubular joints meet or exceed their design life, except for one joint (node 370). This joint’s service life extends from 9.3 years to 27.0 years by applying a burr grinding weld-profiling technique, making it compliant with the fatigue criteria. By systematically combining linear, nonlinear, and fatigue-based analyses, the proposed framework enables robust multi-hazard verification of marine platforms. It provides operators and engineers with clear strategies for reinforcing existing structures and guiding future developments to ensure safe long-term performance. Full article
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19 pages, 10178 KiB  
Article
Optimization of Laser Welding Parameters and Fixed Stress Span Design to Minimize Deformation in Ultra-Thin Ferritic Stainless Steel
by Jinlong Su, Jingyi Li, Kaining Zhu, Fei Xing, Xiaoming Qiu and Jingwei Liang
Metals 2025, 15(3), 325; https://doi.org/10.3390/met15030325 - 17 Mar 2025
Cited by 1 | Viewed by 649
Abstract
Ultra-thin ferritic stainless steel, essential for applications such as proton exchange membrane fuel cells, presents challenges during pulsed laser welding due to thermal stresses causing deformation. This study explores the effects of welding parameters and clamp design on deformation through finite element simulations [...] Read more.
Ultra-thin ferritic stainless steel, essential for applications such as proton exchange membrane fuel cells, presents challenges during pulsed laser welding due to thermal stresses causing deformation. This study explores the effects of welding parameters and clamp design on deformation through finite element simulations and experiments. Key parameters, including laser power (500–700 W), welding speed (6–14 mm/s), and pulse frequency (6–14 Hz), were systematically varied. Results revealed a non-linear relationship between these parameters and weld quality, with the optimal combination identified as a laser power of 600 W, welding speed of 10 mm/s, and pulse frequency of 10 Hz. Additionally, the fixed stress span applied by clamps significantly influenced stress–strain and displacement fields. For instance, residual stress decreased from 267 MPa at a 5 mm span to 189 MPa at a 20 mm span. Displacement values increased from 4.746 × 10⁻3 mm at 5 mm to 8.111 × 10⁻3 mm at 20 mm, while strain initially decreased but rose slightly from 1.648 × 10⁻3 at 10 mm to 1.719 × 10⁻3 at 15 mm. The 5 mm stress span was found optimal, producing a smooth and defect-free weld surface. This study bridges gaps in understanding the deformation mechanics of ultra-thin ferritic stainless steel, offering practical guidelines for optimizing laser welding parameters and clamp designs to achieve superior weld quality. Full article
(This article belongs to the Section Welding and Joining)
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9 pages, 2335 KiB  
Proceeding Paper
The Advanced Real-Time Monitoring of New Welding Processes in the Aircraft Industry
by David Castro, Julio Illade, Noelia Gonzalez, Soralla Pintos and Massimiliano Russello
Eng. Proc. 2025, 90(1), 7; https://doi.org/10.3390/engproc2025090007 - 10 Mar 2025
Viewed by 918
Abstract
While the monitoring techniques employed are well established in other fields, their application to the novel processes of ultrasonic and resistance welding of composites is innovative. This study details the adaptation of these techniques to monitor the essential parameters that influence the quality [...] Read more.
While the monitoring techniques employed are well established in other fields, their application to the novel processes of ultrasonic and resistance welding of composites is innovative. This study details the adaptation of these techniques to monitor the essential parameters that influence the quality of welds in composite materials within the context of the MFFD (Multi-Functional Fuselage Demonstrator) during the WELDER project. This article presents findings from the application of a sophisticated monitoring system to new welding processes for composites, demonstrating significant enhancements in process control, quality assurance, and operational safety. In ultrasonic welding, temperature, speed, power, amplitude, and displacement were monitored, whereas in resistance welding, voltage, load, and temperature were tracked. This comprehensive data collection is crucial due to the sensitivity of composite materials to welding parameters, which directly affect the integrity and performance of the final product. The data transmission utilized the OPC UA protocol, ensuring secure, reliable real-time data flow to visualization interfaces in safe environments. The integration of real-time monitoring and advanced data analysis helps in identifying potential defects during the welding process, thereby enhancing both the reliability and efficiency of composite welding. The results underscore the potential of these technologies to advance the manufacturing practices for high-performance composite materials in the aeronautics field. Full article
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14 pages, 3787 KiB  
Article
Investigation of the Microstructure and Mechanical Properties of Heat-Treatment-Free Die-Casting Aluminum Alloys Through the Control of Laser Oscillation Amplitude
by Hong Xu, Jinyi Shao, Lijun Han, Rui Wang, Zhigong Jiang, Guanghui Miao, Zhonghao Zhang, Xiuming Cheng and Ming Bai
Materials 2025, 18(6), 1194; https://doi.org/10.3390/ma18061194 - 7 Mar 2025
Viewed by 760
Abstract
In this study, laser oscillation welding was utilized to offer an effective solution for the joint welding of heat-treatment-free die-cast aluminum alloys, which expands the practical applications of automotive structural parts and heat sinks for electronic devices. The effects of oscillation amplitude on [...] Read more.
In this study, laser oscillation welding was utilized to offer an effective solution for the joint welding of heat-treatment-free die-cast aluminum alloys, which expands the practical applications of automotive structural parts and heat sinks for electronic devices. The effects of oscillation amplitude on the macro-morphology, microstructure, and properties of the alloy weld were examined, and a molten pool flow model was developed to compare the behavior of the molten pool with and without oscillation. The results show that increasing the oscillation amplitude eliminates the coarse Al15(Fe,Mn)3Si2 phase, resulting in a finer and more uniform distribution of the eutectic Si and Mg2Si phases. At an oscillation amplitude of 7 mm, the maximum tensile shear load and displacement were 2761 N and 1.17 mm, respectively. Laser oscillation was found to enhance the fluidity of the molten pool, reduce porosity, improve weld quality, and effectively decrease cracks and inhomogeneous grain distribution. These findings provide a research basis for optimizing the laser oscillation welding process and for the practical welding of fabricated devices. Full article
(This article belongs to the Section Metals and Alloys)
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21 pages, 5078 KiB  
Article
Innovative Approach Integrating Machine Learning Models for Coiled Tubing Fatigue Modeling
by Khalil Moulay Brahim, Ahmed Hadjadj, Aissa Abidi Saad, Elfakeur Abidi Saad and Hichem Horra
Appl. Sci. 2025, 15(6), 2899; https://doi.org/10.3390/app15062899 - 7 Mar 2025
Viewed by 922
Abstract
Coiled tubing (CT) plays a pivotal role in oil and gas well intervention operations due to its advantages, such as flexibility, fast mobilization, safety, low cost, and its wide range of applications, including well intervention, cleaning, stimulation, fluid displacement, cementing, and drilling. However, [...] Read more.
Coiled tubing (CT) plays a pivotal role in oil and gas well intervention operations due to its advantages, such as flexibility, fast mobilization, safety, low cost, and its wide range of applications, including well intervention, cleaning, stimulation, fluid displacement, cementing, and drilling. However, CT is subject to fatigue and mechanical damage caused by repeated bending cycles, internal pressure, and environmental factors, which can lead to premature failure, high operational costs, and production downtime. With the development of CT properties and modes of application, traditional fatigue life prediction methods based on analytical models integrated in the tracking process showed, in some cases, an underestimate or overestimate of the actual fatigue life of CT, particularly when complex factors like welding type, corrosive environment, and high-pressure variation are involved. This study addresses this limitation by introducing a comprehensive machine learning-based approach to improve the accuracy of CT fatigue life prediction, using a dataset derived from both lab-scale and full-scale fatigue tests. We incorporated the impact of different parameters such as CT grades, wall thickness, CT diameter, internal pressure, and welding types. By using advanced machine learning techniques such as artificial neural networks (ANNs) and Gradient Boosting Regressor, we obtained a more precise estimation of the number of cycles to failure than traditional models. The results from our machine learning analysis demonstrated that CatBoost and XGBoost are the most suitable models for fatigue life prediction. These models exhibited high predictive accuracy, with R2 values exceeding 0.94 on the test set, alongside relatively low error metrics (MSE, MAE and MAPE), indicating strong generalization capability. The results of this study show the importance of the integration of machine learning for CT fatigue life analysis and demonstrate its capacity to enhance prediction accuracy and reduce uncertainty. A detailed machine learning model is presented, emphasizing the capability to handle complex data and improve prediction under diverse operational conditions. This study contributes to more reliable CT management and safer, more cost-efficient well intervention operations. Full article
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14 pages, 4352 KiB  
Article
Multiphysics Analysis Process of Front-End Process for Induction Hardening of 3D Structures to Predict Structural Deformation
by Soonjae Hwang, Sarang Yi, Jongkyu Park and Seokmoo Hong
Appl. Sci. 2025, 15(5), 2410; https://doi.org/10.3390/app15052410 - 24 Feb 2025
Viewed by 504
Abstract
The torsion beam, integral to rear suspension systems in vehicles, is a critical component where strength and durability must be prioritized in specific regions. To enhance the strength of these regions, induction hardening, a localized heat treatment method, is employed. However, the application [...] Read more.
The torsion beam, integral to rear suspension systems in vehicles, is a critical component where strength and durability must be prioritized in specific regions. To enhance the strength of these regions, induction hardening, a localized heat treatment method, is employed. However, the application of this treatment introduces distortion, which compromises the precision of welding between components and raises significant concerns about product quality and safety. To address these challenges, the present study introduces a front-end analysis process for induction hardening aimed at predicting distortion following heat treatment. A three-dimensional model of the product was utilized to simulate the front-end process of induction hardening. A coupled analysis of electrical and thermal fields was conducted to replicate the heating effect induced by coils during the heat treatment process. Additionally, a thermo-structural coupled analysis was performed to predict the distortion occurring during the cooling phase. A comparative analysis with actual product measurements demonstrated that the proposed method achieved a distortion displacement prediction accuracy of 98%, thereby validating the efficacy of the proposed analysis process. Full article
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18 pages, 7069 KiB  
Article
Mechanics and Heat Transfer Design of Thorium Metal Target Protection Thin Film in Isotope Production in Gansu Province
by Yuqi Liu, Jianrong Zhang, Weiming Liu, Lidong Ma, Mengke Wang, Yaling Zhang, Lei Yang and Yangyang Yang
Energies 2025, 18(4), 928; https://doi.org/10.3390/en18040928 - 14 Feb 2025
Viewed by 558
Abstract
Isotopes are important strategic materials, and are irreplaceable and central to the fields of national defence, energy security, medical health, and scientific research. With the demonstrated efficacy of targeted alpha therapy using 225Ac, there is a pressing need to explore radiopharmaceuticals capable [...] Read more.
Isotopes are important strategic materials, and are irreplaceable and central to the fields of national defence, energy security, medical health, and scientific research. With the demonstrated efficacy of targeted alpha therapy using 225Ac, there is a pressing need to explore radiopharmaceuticals capable of delivering consistent and ample quantities of 225Ac. Isotope production in Gansu Province has initiated the production of 225Ac via bombardment of thorium metal with 480 MeV protons. To ensure the stability and safety of thorium targets under high-power beam conditions, this study proposes a novel packaging design for the protective layer of thorium targets, accompanied by detailed mechanical and thermal analyses. The study employs an Inconel 718 alloy as the film material for vacuum welding packaging, and simulates local displacement variations in the Inconel 718 film under different thicknesses, lengths, gaps, and flange fillet conditions. The optimal parameter settings that meet the design requirements are then determined. Additionally, beam energy deposition is assessed using Monte Carlo N-Particle (MCNP 6) neutron calculation software, while the heat transfer process is simulated with Fluent software to optimize the cooling mechanism, ensuring the stability and safety of the target material. The final design provides a theoretical foundation for isotope production targets in Gansu Province. Full article
(This article belongs to the Special Issue Economic Analysis of Nuclear Energy)
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18 pages, 8354 KiB  
Article
Optimization of Plasma Welding Sequence and Performance Verification for a Fork Shaft: A Comparison of Same-Direction and Reverse-Direction Welding
by Jianguang Yang, Peigang Cao, Jiaqing Yao, Junyong Wang, Qilin Mao and Yu Yang
Materials 2025, 18(2), 288; https://doi.org/10.3390/ma18020288 - 10 Jan 2025
Viewed by 940
Abstract
The shift fork shaft is a key component in transmissions, connecting the shift fork in order to adjust the gear engagement. This study investigates the effects of different welding sequences on deformation and residual stress during plasma welding of the shift fork shaft. [...] Read more.
The shift fork shaft is a key component in transmissions, connecting the shift fork in order to adjust the gear engagement. This study investigates the effects of different welding sequences on deformation and residual stress during plasma welding of the shift fork shaft. A temperature-displacement coupled finite element method, using ABAQUS simulation software and a double ellipsoid heat source model, was employed for the numerical analysis. The simulation results show that welding in the same and opposite directions leads to opposite deformation directions but similar deformation magnitudes. However, opposite-direction welding generates more significant stress concentration. After determining an optimal welding process, experimental welding was conducted. Microstructural observations of the weld seam and critical areas, along with mechanical property tests, revealed that the welds were well formed with no surface defects. The heat-affected zone (HAZ) exhibited a mixture of martensitic and non-martensitic phases, while the fusion zone (FZ) underwent phase transformation and recrystallization, forming fine-grained ferrite with martensite. Microhardness (HRC) in the weld seam ranged from 35 to 50, with the FZ and HAZ hardness higher than that of the base material (BM). The second weld pass showed significantly higher hardness in the FZ than the first pass. The tensile strength of the weld joint reached 94% of the base material strength, though plasticity and toughness were reduced. Fracture surface analysis indicated a combination of brittle cleavage and localized plastic deformation. Full article
(This article belongs to the Special Issue Advances in Welding Process and Materials (2nd Edition))
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