Journal of Advanced Joining Processes最新文献

{"title":"Butt-joint welding process of PVC Profiles: Numerical modelling, experimental validation and insights into material behaviour and flow dynamics","authors":"Riccardo Panciroli ,&nbsp;Daniele Chiappini ,&nbsp;Roberto Palazzetti","doi":"10.1016/j.jajp.2026.100374","DOIUrl":"10.1016/j.jajp.2026.100374","url":null,"abstract":"<div><div>Polyvinyl chloride (PVC) forming operations are typified by large deformations, free-surface condition, complex conjugate heat transfer, and intricate contact phenomena. This study focuses on numerical modelling of the forming process that occurs beneath the butt-joint welding of polymeric profiles to offer a comprehensive understanding of how process parameters and boundary conditions influence the final weld. Numerical simulations are based on arbitrary and coupled Lagrangian and Eulerian models, which incorporate viscoelasticity, heat transfer, external forces, and free-surface flow. Due to the extensive temperature range encountered during the process, during heating the material transitions from a linear elastic state to a low-viscosity fluid. Consequently, the model has been developed to simultaneously solve for both solid and free-surface fluid conditions, and PVC has been modelled as a temperature-dependent viscoelastic solid, exhibiting Newtonian-like fluid characteristics under high temperatures. The proposed numerical solution methodology is employed to offer insights into the physics of the butt-welding process, widely utilised within industry. Two distinct configurations have been modelled to study material flow during the process: with and without a rigid constrain that prevents the material from moving freely upwards. These simulations aim to illuminate the impact of boundary conditions and physical constraints on the welding process and material behaviour.</div></div>","PeriodicalId":34313,"journal":{"name":"Journal of Advanced Joining Processes","volume":"13 ","pages":"Article 100374"},"PeriodicalIF":4.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145925870","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Material-specific beam-plume interactions during deep-penetration laser welding of stainless steel, aluminum, and copper","authors":"Johannes Wahl ,&nbsp;Christian Frey ,&nbsp;John Powell ,&nbsp;Michael Haas ,&nbsp;Simon Olschok ,&nbsp;Uwe Reisgen ,&nbsp;Christian Hagenlocher ,&nbsp;Thomas Graf","doi":"10.1016/j.jajp.2025.100366","DOIUrl":"10.1016/j.jajp.2025.100366","url":null,"abstract":"<div><div>During deep-penetration laser welding, a hot vapor plume is emitted from the keyhole which, on cooling, condenses into a particle cloud that surrounds the weld zone. This vapor plume and associated particle cloud interact with the incident laser beam through scattering, absorption, and phase front distortion, dynamically altering the beam caustic and potentially affecting weld quality. In this study, the mechanisms governing the beam-plume interaction are investigated by observation of the thermal emission and scattered laser light from the interaction zone during the welding of stainless steel, aluminum, and copper. For this analysis, a spectrometer and a high-speed camera equipped with optical filters were used. The results revealed significant material-specific differences in thermal emission and scattered laser light from the plume, indicating variations in absorption and scattering behavior and thus beam attenuation. Re-heating of plume material until evaporation took place for all three materials. Stainless steel exhibited the strongest thermal emission, while aluminum and copper showed significantly weaker emission. In contrast, the aluminum plume displayed the highest level of laser light scattering. This is attributed to the presence of liquid and solid particles rather than purely vaporized material, even close to the laser beam focus. Distinct interaction zones within the laser beam caustic were identified, each corresponding to specific aggregate states and characteristic laser-plume interactions. For stainless steel and copper, a zone forms close to the keyhole which is primarily composed of vaporized material. Beyond this there is a multi-phase zone containing both vapor and liquid or solid matter. Further from the keyhole, a particle zone with no detectable vapor appears as re-heating becomes insufficient for evaporation. In aluminum, no distinct vapor zone was detected. Instead, strong scattering near the keyhole indicates the presence of particles even at high laser intensities. Thus, only a multi-phase and a particle zone appear to form for aluminum under the welding parameters used.</div></div>","PeriodicalId":34313,"journal":{"name":"Journal of Advanced Joining Processes","volume":"13 ","pages":"Article 100366"},"PeriodicalIF":4.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145665318","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"AI-based monitoring system for real-time defect detection in wire arc additive manufacturing","authors":"J.E. Tapia Cabrera,&nbsp;F. Groschupp,&nbsp;F. Riegger,&nbsp;M.F. Zaeh","doi":"10.1016/j.jajp.2025.100371","DOIUrl":"10.1016/j.jajp.2025.100371","url":null,"abstract":"<div><div>The high flexibility of additive manufacturing (AM) enables the repair of components with complex geometries, contributing to the sustainability of the economy by reducing waste and increasing product lifetime. Wire arc additive manufacturing (WAAM) is well-suited for repair due to the high deposition rates compared to other AM technologies. Moreover, the automation potential of WAAM offers a promising opportunity for increasing productivity. However, the automated repair presents new challenges for quality assurance. During the deposition of successive layers, defects, such as a lack of fusion between adjacent weld beads, may be concealed within the parts. Due to their impact on the mechanical properties, such discontinuities constitute non-conformities and require part rejection. Therefore, a real-time monitoring system is required to detect lack of fusion defects and to ensure the reliable performance of the repaired components. Weld pool imaging provides detailed insights into process anomalies. Nonetheless, the harsh welding environment degrades the data quality and requires advanced imaging algorithms to extract features for a reliable analysis. The artificial intelligence (AI) architecture “You Only Look Once” (YOLO) allows for a robust detection performance and real-time capability with its one-stage approach for object detection. In this work, a monitoring system using two sequentially coupled YOLO-based models was developed. First, a detection model identifies the lack of fusion defects within the weld pool images, producing bounding boxes around the detected areas. These bounding boxes are then used as an input for a segmentation model, which provides a more precise delineation of the defects within the identified regions. The models were evaluated on unseen data, achieving a recall of over 90 % while maintaining real-time capability. This result showed the high potential of AI-based monitoring systems for real-time defect detection in WAAM to ensure the quality of the repaired components.</div></div>","PeriodicalId":34313,"journal":{"name":"Journal of Advanced Joining Processes","volume":"13 ","pages":"Article 100371"},"PeriodicalIF":4.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145925883","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of joint shapes for friction welding between 7075-T6 Al alloy and low carbon steel with an insert metal of pure Ti","authors":"Masaaki Kimura ,&nbsp;Yuki Tamakoshi ,&nbsp;Masahiro Kusaka ,&nbsp;Koichi Kaizu","doi":"10.1016/j.jajp.2026.100373","DOIUrl":"10.1016/j.jajp.2026.100373","url":null,"abstract":"<div><div>Direct friction welding between type 7075-T6 aluminum alloy (AA7075) and low carbon steel (LCS) is particularly difficult, as cracking often form in the AA7075 flash and propagate to the weld interface during the welding process. This study investigated the simultaneous friction welding of AA7075 and LCS using commercially pure titanium (CP-Ti) as an insert metal in a single-step process, with the aim of achieving a joint free of cracks into the AA7075 flash. The joint free of cracks into the AA7075 flash was not obtained by varying of only the shape of the CP-Ti insert metal. However, flash cracking could be prevented when the weld diameter of the AA7075 side was larger than that diameter of the CP-Ti insert metal, and used with a suitable shape of CP-Ti insert metal having the groove to the AA7075 side. Furthermore, the joint having high tensile strength exceeding the yield strength of the LCS base metal was achieved; specifically, a forge pressure of 400 MPa resulted in approximately 83% of the tensile strength of the LCS base metal. Despite these improvements, the good joint such as fracture occurring within the LCS base metal could not be realized, since the adjacent region of the LCS side is not much deformed even if the joint is made with high forge pressure. Hence, further optimization of the CP-Ti insert metal shape is essential to promote greater deformation of the LCS side and enhance overall joint characteristics.</div></div>","PeriodicalId":34313,"journal":{"name":"Journal of Advanced Joining Processes","volume":"13 ","pages":"Article 100373"},"PeriodicalIF":4.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145925871","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical investigation of an orbital forming process to join dissimilar materials with local material accumulation","authors":"A. Harms,&nbsp;D. Römisch,&nbsp;D. Reisacher,&nbsp;M. Lechner,&nbsp;M. Merklein","doi":"10.1016/j.jajp.2025.100372","DOIUrl":"10.1016/j.jajp.2025.100372","url":null,"abstract":"<div><div>Increasing demands for lightweight design and functional integration in modern production technology require innovative manufacturing processes. Multi-material systems offer a high potential to face these challenges by reducing weight while maintaining strength. A new approach of an orbital forming process to join dissimilar materials while simultaneously achieve a local thickening offers a reduced number of required parts since there is no need for auxiliary elements and high material efficiency due to near-net-shape design. In this context, this research provides the design and validation of a numerical simulation model for joining by orbital forming with local material accumulation in a single step. The hybrid component consists of an inner aluminum blank of EN AW-5754 and an outer steel ring made of DP600 both with an initial sheet thickness of 3.0 mm. The steel ring features cut-outs on the inside to provide a form closure in tangential direction. The primary aim of the simulation model is to predict and analyze the material flow during the forming process as well as the resulting stress states to evaluate the force closure. Furthermore, preliminary experimental investigations show a significant influence of the positioning of the steel cut-outs in relation to the locally thickened areas on the joint formation. This effect will be further analyzed using the numerical model to gain a deeper understanding of the cause-and-effect relations. Based on experimental investigations the numerical model will be validated by comparing the resulting sheet thickness distribution and the geometric and mechanical properties at the joint for several parameter combinations. The validated numerical model will then be used for an optimization of the joint positioning regarding the resulting material flow in the joint area. This approach provides a fundamental understanding on the mechanisms affecting this combined forming and joining process. In addition, this numerical tool offers an approach for designing local thickened hybrid components with various geometries and material combinations regarding the positioning of the joint in relation to the local material accumulation.</div></div>","PeriodicalId":34313,"journal":{"name":"Journal of Advanced Joining Processes","volume":"13 ","pages":"Article 100372"},"PeriodicalIF":4.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145925872","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of the effect of stress ratio on fatigue life in a microstructure-sensitive fatigue model for ultimate grain refinement and initiation grain refinement of high-speed friction stir welding of AA6061-T6 to Cu","authors":"Esmaeil Mirmahdi ,&nbsp;Davood Afshari ,&nbsp;Masoud Mahmoodi","doi":"10.1016/j.jajp.2025.100367","DOIUrl":"10.1016/j.jajp.2025.100367","url":null,"abstract":"<div><div>The formation of an ultimate grain refinement (UGR) microstructure in high-speed friction stir welding (HSFSW) significantly improves the mechanical properties of dissimilar joints. This study shows that achieving this microstructure not only increases tensile strength by up to 177 MPa (equivalent to 80% of the base metal strength of Cu) but also substantially enhances the fatigue resistance of the samples. To investigate fatigue behavior, tests were conducted under three different stress ratios (<em>R</em> = 0.1, <em>R</em> = 0.5, and <em>R</em> = -1). A microstructure-sensitive fatigue model (MSF-FEM) was developed to simulate the fatigue life of samples in both the initial grain refinement (IGR, coarse-grained) and ultimate grain refinement (UGR, ultrafine-grained) states. Modeling and experimental results indicated that as the R increased (from -1 towards 0.1), fatigue life decreased, with the longest fatigue life observed under fully reversed loading conditions (<em>R</em> = -1). Under these conditions, the fatigue life of UGR samples reached 4.8 ☓ 10⁴ cycles, and IGR samples reached 3.5 ☓ 10⁴ cycles. The results showed that UGR samples, compared to IGR, had an average increase of over 100% in fatigue life at different R; specifically, this improvement reached 100% at <em>R</em> = 0.1, 167% at <em>R</em> = 0.5, and 37% at <em>R</em>=-1. These findings indicate the simultaneous and significant effect of optimal microstructure and loading conditions on increasing the fatigue life of HSFSW joints.</div></div>","PeriodicalId":34313,"journal":{"name":"Journal of Advanced Joining Processes","volume":"13 ","pages":"Article 100367"},"PeriodicalIF":4.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145926533","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Generation of undercuts using cw-laser structuring as a surface pre-treatment for thermally joined metal-polymer hybrids","authors":"Benjamin Förster,&nbsp;Tobias Geis,&nbsp;Maurice Langer","doi":"10.1016/j.jajp.2026.100376","DOIUrl":"10.1016/j.jajp.2026.100376","url":null,"abstract":"<div><div>Pulsed laser systems are often used for surface pre-treatment prior to thermal direct joining, as they enable the creation of undercuts but their process speeds are too low for industrial applications. Continuous wave (cw) laser structuring is a promising alternative that can achieve high area rates of up to 200 mm²/s, representing a 10- to 100-fold increase. Although this allows high strengths to be generated in the shear direction, the strength in the normal direction is significantly lower due to the lack of undercuts. To address the latter problem, this study investigates three laser structuring strategies known as ‘oblique irradiation’, ‘hollowing bottom’ and ‘remelting top’. They aim to create defined undercuts to enhance mechanical interlocking between cold-rolled DP1000 steel and carbon fibre-reinforced PA6. The strategies were evaluated through metallographic analysis and mechanical testing in tensile shear and cross-lap tensile configurations. Among the approaches, the “Hollowing bottom” strategy demonstrated superior performance, achieving a maximum tensile shear strength of 30.3 MPa. A subsequent optimisation loop of this structuring strategy based on the principle of ‘design of experiments’ (DoE) revealed that the morphology of the undercut and reproducibility have a significant influence on the bond strength, especially under peel load. This resulted in a 40% increase in head tensile strength compared to the reference and to demonstrate the clear benefits of undercut surface structures. The findings highlight the potential of optimized cw-laser structuring to improve joint reliability in lightweight hybrid applications.</div></div>","PeriodicalId":34313,"journal":{"name":"Journal of Advanced Joining Processes","volume":"13 ","pages":"Article 100376"},"PeriodicalIF":4.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146077966","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of secondary aluminum content on casting and weldability of high pressure die cast materials for sustainable automotive body concepts","authors":"Dirk Dittrich ,&nbsp;Dirk Lehmhus ,&nbsp;Marco Haesche ,&nbsp;Leonardo Fernandes Gomes ,&nbsp;Christoph Pille ,&nbsp;Axel Jahn ,&nbsp;Linda Ullmann ,&nbsp;Charlotte Graner","doi":"10.1016/j.jajp.2025.100361","DOIUrl":"10.1016/j.jajp.2025.100361","url":null,"abstract":"<div><div>Sustainability is becoming increasingly important in vehicle production. The e-mobility transition has shifted the CO₂ footprint from use to production phase, where secondary aluminum alloys in structural castings are known to offer significant CO₂ reduction potential. However, accumulation of copper, iron, manganese and zinc and the hydrogen content in the melt pose major challenges for casting and subsequent joining processes. In laser welding, dynamic modulation of intensity distributions in the weld pool can overcome the latter issue. In experimental studies covering high pressure die-cast AlSi10MnMg alloys with secondary material content levels ranging from 0 wt.-% and 58 wt.-% to 89 wt.-%, castability and weldability were investigated and the structural and mechanical properties of the joint determined. The results contribute to the optimization of sustainable car body production, providing a path towards cost-effective differential lightweight design solutions as economically, technologically and ecologically competitive alternatives to large-scale casting technologies (GigaCasting).</div></div>","PeriodicalId":34313,"journal":{"name":"Journal of Advanced Joining Processes","volume":"13 ","pages":"Article 100361"},"PeriodicalIF":4.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145738200","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Manufacturing and predicted fatigue behaviour of welds using the low-transformation-temperature (LTT) effect","authors":"M. Clemens ,&nbsp;M. Gamerdinger ,&nbsp;S. Olschok ,&nbsp;U. Reisgen ,&nbsp;T. Geers ,&nbsp;J. Voelkel ,&nbsp;H. Bartsch","doi":"10.1016/j.jajp.2026.100382","DOIUrl":"10.1016/j.jajp.2026.100382","url":null,"abstract":"<div><div>Fatigue strength often governs the design of welded steel. Conventional methods to improve fatigue performance, such as post-weld grinding or hammer peening, require additional manufacturing steps and are rarely applied in practice. An alternative approach is the Low-Transformation-Temperature (LTT) effect, which introduces compressive residual stresses via controlled martensitic phase transformations during welding. In this work, the submerged arc welding process was adapted to implement LTT welding using in situ alloying with commercially available high-alloy filler wires, enabling reproducible stress modification without additional post-treatment. Macroscopic weld inspection confirmed consistent geometry and defect-free seams, while EDS analysis revealed uniform chromium and nickel distribution. Hardness mapping showed a significant increase up to approximately 450 HV10, indicating successful martensitic transformation. Evaluation of an extended European fatigue database including LTT welds demonstrated fatigue strength improvements of 11 to 60 % for butt-welded joints and longitudinal stiffeners. Planned fatigue tests with precisely controlled cyclic loading and strain measurements will further quantify fatigue performance and scatter. These initial results confirm that LTT welding is a promising and cost-effective method to enhance fatigue strength in welded steel structures.</div></div>","PeriodicalId":34313,"journal":{"name":"Journal of Advanced Joining Processes","volume":"13 ","pages":"Article 100382"},"PeriodicalIF":4.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146188480","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Deep learning-powered vision system for seam-tracking and gap width estimation in robotic laser welding","authors":"Matteo Moscatelli ,&nbsp;Mara Tanelli ,&nbsp;Ali Gökhan Demir","doi":"10.1016/j.jajp.2026.100377","DOIUrl":"10.1016/j.jajp.2026.100377","url":null,"abstract":"<div><div>The increasing adoption of robotic laser welding highlights the need for advanced seam-tracking systems to ensure precision, adaptability, and high-quality welds. Conventional methods struggle with fixturing errors, part-to-part variations, thermal deformation, and challenges related to material reflectivity. This work presents a deep learning-based vision system designed for real-time seam tracking and gap width estimation, addressing these limitations by leveraging state-of-the-art computer vision techniques. The system employs the YOLO (You Only Look Once) architecture for seam detection and a MobileNet-based Convolutional Neural Network (CNN) for gap width estimation, ensuring robust performance under variable lighting conditions and reflective surfaces. By processing coaxial images acquired during welding processes, the system accurately identifies the seam position and discretizes the trajectory into a sequence of key points. This information can then be used for further processing or integration with robotic motion control strategies. Experimental validation on an industrial robotic laser welding setup demonstrates the system’s capability to enhance tracking precision, minimize positioning errors, and support high-speed welding operations. The results confirm that deep learning-based vision systems play a crucial role in advancing autonomous robotic welding, increasing flexibility and efficiency in smart manufacturing.</div></div>","PeriodicalId":34313,"journal":{"name":"Journal of Advanced Joining Processes","volume":"13 ","pages":"Article 100377"},"PeriodicalIF":4.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146188468","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}