Journal of Advanced Joining Processes最新文献

{"title":"A novel approach to control thermal induced buckling during laser welding of battery housing through a unilateral N-2-1 fixturing principle","authors":"","doi":"10.1016/j.jajp.2024.100256","DOIUrl":"10.1016/j.jajp.2024.100256","url":null,"abstract":"<div><div>Battery housing (BH) in modern electric vehicles must meet demanding functional requirements. The design and geometry of the BH become intricate to prevent damage during collisions and to ensure absolute impermeability to gases and water during operation. Moreover, in the pursuit of a lightweight BH, manufacturers rely on high-strength 6xxx aluminium alloys, posing significant challenges for the welding processes. It is estimated that up to 30 m of weld length is required during the construction of battery housings including joining the lid and under-shield to the main structural frame and joining the ribs to the frame for standard vehicles. Due to the increasing use of thin sheets for lightweighting the structure, thermal-induced buckling may occur and generate critical dimensional unconformities going beyond design tolerances. This underpins the need to optimise fixturing design to control thermal-induced buckling.</div><div>This paper goes beyond the state-of-the-art “N-2-1″ approaches for fixturing thin and deformable parts and proposes the new principle of “unilateral N-2-1 fixturing”. The driving idea is adding unilateral restraints to the direction of thermal contraction, which ultimately causes buckling; and, keeping the direction where the thermal expansion occurs in a free state. The methodology is based on three main steps: (1) physics-based modelling of parts and fixtures using a thermo-mechanical FEA simulation; (2) calibration of the weld heat source using metallographic data; (3) validation using optical scanning technology. The methodology was demonstrated during the laser beam welding of a high-strength aluminium 6xxx thin deformable lid to a rigid high-strength 6xxx aluminium extrusion frame. Results indicated that the thermal induced buckling deformation was reduced from 15 mm, when using the state-of-the-art fixturing approach, to approximately 2 mm with the proposed methodology.</div></div>","PeriodicalId":34313,"journal":{"name":"Journal of Advanced Joining Processes","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2024-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142421590","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High strain rate tensile deformation of similar and dissimilar AA6082 and AA7075 friction-stir-welded blanks","authors":"","doi":"10.1016/j.jajp.2024.100254","DOIUrl":"10.1016/j.jajp.2024.100254","url":null,"abstract":"<div><div>Friction-stir-welding process has become an established solid-state technique for joining of dissimilar lightweight materials over the past decade by overcoming fundamental welding challenges such as solidification cracking, phase segregation and surface oxidation. Despite these unique capabilities, the resulting microstructure feature in the weld zone consisting of fine grains with a high dislocation density, challenges further heat treatment and forming processes. Hence, a high solution annealing temperature results in degradation of the adjusted microstructure and in a lower to reduced mechanical properties in case of dissimilar joints of precipitation-hardenable aluminum alloys. Subsequent hot forming therefore involves a great effort and requires further heat treatment steps. Thus, the present study investigates the effect of a recently introduced novel thermo-mechanical forming process on local deformation behavior of similar as well as dissimilar joints processed by friction-stir-welding technique of thin-walled AA6082 and AA7075 blanks. To avoid the complete elimination of the adjusted microstructure, the welding process is performed after a thermo-mechanical process consisting of solution annealing, die cooling and peak aging. Uniaxial tensile tests are then carried out at high strain rates ranging from <span><math><mover><mrow><mi>ε</mi></mrow><mi>˙</mi></mover></math></span> = 40 s^-1 to <span><math><mover><mrow><mi>ε</mi></mrow><mi>˙</mi></mover></math></span> = 400 s^-1. The results show an increase in yield and ultimate tensile strength as well as in total elongation after failure with increasing strain rates. As the strain rate increases, the flow stress of similar weld of AA7075 is higher than those of AA6082 and the dissimilar weld of AA6082 and AA7075. Local deformation measurements reveal higher strain localization in the welded zone for similar welds, which leads to micro-crack initiation and failure due to strain accumulation. Microstructure analysis shows very fine equiaxed grain structure in the nugget zone and homogenous distribution of precipitates after friction stir welding process, which explain the plastic deformation behavior.</div></div>","PeriodicalId":34313,"journal":{"name":"Journal of Advanced Joining Processes","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142323138","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of the media tightness of a microform-fitted plastic/light metal composite","authors":"","doi":"10.1016/j.jajp.2024.100253","DOIUrl":"10.1016/j.jajp.2024.100253","url":null,"abstract":"<div><p>Plastic/metal hybrid components made of amorphous thermoplastics such as polycarbonate and light metals such as aluminum offer potential to be used in modern automotive headlights to meet the high requirements for tolerances and surface quality. A microform-fit joining approach is used to join plastics and metals, which combines the advantages of material-fit and form-fit joining processes while at the same time avoiding some of the disadvantages of the respective joining approaches, such as stress peaks or the use of additional chemicals. For this purpose, the light metal component is microstructured through laser ablation. To ensure the functional safety of electrical components, the media tightness of the hybrid component is tested with a pressure drop test. An influence of the structure arrangement, the structure spacing and the molding compound on the media tightness can be determined. The highest media tightness can be achieved with a ring-shaped structural arrangement in which the microstructures are orientated orthogonally to the outlet direction of the test medium. The media permeability of a ring-shaped structure arrangement with a structure spacing of 500 µm is 0.42 cm³/s for test specimens made of aluminum and polycarbonate. As the value is below the threshold value of 12 cm³/s, watertightness up to an overpressure of at least 0.5 bar can be concluded.</p></div>","PeriodicalId":34313,"journal":{"name":"Journal of Advanced Joining Processes","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666330924000694/pdfft?md5=99e3d6f0213567ef7569418dfa402a69&pid=1-s2.0-S2666330924000694-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142240771","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterization and modeling of laser transmission welded polyetherketoneketone (PEKK) joints: Influence of process parameters and annealing on weld properties","authors":"","doi":"10.1016/j.jajp.2024.100252","DOIUrl":"10.1016/j.jajp.2024.100252","url":null,"abstract":"<div><p>Welding high-performance thermoplastics has gained popularity across various industries such as automotive, aerospace, and medical. Laser transmission welding (LTW) has emerged as an effective method for joining thermoplastic parts due to its precise control and high joint quality. PAEK (polyaryletherketone) are wide spreading over various industrial applications as a substitute to metals and thermosets when high durability and performance are required. Polyetherketoneketone (PEKK) is one of these PAEK and it has received less attention than PEEK until now. PEKK, being a semi-crystalline thermoplastic, requires additional care during processing due to its propensity to crystallize. This study presents both experimental and numerical investigations into LTW of PEKK molded parts, aiming to understand the influence of welding parameters and crystallinity on weld joint morphology and mechanical properties. PEKK plates, prepared in amorphous and semi-crystalline states, are subjected to LTW using a 975 nm diode laser. Material characterization confirms differences in crystallinity between the samples, which affect their thermal and optical properties, which are crucial for welding. Welding tests are conducted with varying laser power (between 75 and 95 W) and semi-transparent part thickness (2 and 4 mm). The morphology of joints is analysed. Assemblies undergo post-weld annealing treatment to examine its influence on weld crystallinity and consequent mechanical properties. Results reveal an anisotropic distribution of crystallinity within the heat-affected zone (HAZ). The depths of the molten layer (ML) and semi-crystalline layer (scL) vary with laser power and assembly type. A notable decrease in weld strength with laser power is highlighted, while annealing leads to enhanced crystallinity and improved weld strength. Despite variations, high weld strengths are achieved with annealing. Computational modelling elucidates the complex interplay between laser irradiation, temperature distribution, and crystallization kinetics observed experimentally. Overall, this comprehensive investigation provides valuable insights into optimizing LTW parameters for PEKK parts.</p></div>","PeriodicalId":34313,"journal":{"name":"Journal of Advanced Joining Processes","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666330924000682/pdfft?md5=24dcb89e6cc6e498459bac99b4908582&pid=1-s2.0-S2666330924000682-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142240770","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dual-mode laser beam welding of similar and dissimilar material tab-to-busbar for electric vehicle battery pack","authors":"","doi":"10.1016/j.jajp.2024.100250","DOIUrl":"10.1016/j.jajp.2024.100250","url":null,"abstract":"<div><p>The escalation in electric vehicle (EV) adoption necessitates advanced laser joining techniques for critical battery pack components. However, using a standard Gaussian single-mode laser for joining similar and dissimilar material combinations e.g. aluminium/aluminium (Al/Al), aluminium/copper (Al/Cu) for tab-to-busbar connections often led to defects such as cracks and intermetallic compound (IMC) formation. This paper investigates using a dual-mode laser consisting of a core and ring to overcome these issues. In this research, 0.3 mm Al and Cu tabs were welded with 1.5 mm Al and Cu busbars using a 6 kW IPG dual-mode laser at a high welding speed of 1 m s^-1. The study focussed on the effects of dual-mode parameters (i.e. core and ring beam power) and welding speed on tab-to-busbar connections, analysing the interplay between electrical contact resistance, temperature and IMC formation through electrical resistance tests, elemental and strength analysis. The results show, that using the ring beam along with the core beam reduces excessive melting and evaporation of Al and minimises the intermixing of Al and Cu solid solutions in the joint. In the Cu tab-to-Al busbar joint, increasing the ring beam intensity effectively reduces the convexity defect found with single-mode beam attributed to improved keyhole stability. Overall, in dual-mode laser welding, the ring beam protects the keyhole and reduces the IMC formation, while the core beam, with its high peak intensities, controls the penetration depth. This necessitates balancing both core and ring beam intensities for optimal weld quality. Further, the joint resistance for Cu tab-to-Cu busbar (51.90 μΩ) joint was the lowest followed by Cu tab-to-Al busbar (68.38 μΩ) joint, Al tab-to-Cu busbar (84.44 μΩ) joint and Al tab-to-Al busbar (114.12 μΩ) joint.</p></div>","PeriodicalId":34313,"journal":{"name":"Journal of Advanced Joining Processes","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666330924000669/pdfft?md5=5530b89d797a952fb8a294d5495f390b&pid=1-s2.0-S2666330924000669-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142151887","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An energetic approach to the statistical analysis and optimization of friction welding processes applied to an aluminum-steel-joint","authors":"","doi":"10.1016/j.jajp.2024.100251","DOIUrl":"10.1016/j.jajp.2024.100251","url":null,"abstract":"<div><p>The present publication deals with an energy-oriented approach to the statistical analysis of rotational friction welding processes. To illustrate the methodological approach, it is applied to investigate the effects of energy flow on material flow behavior and joint quality during friction welding of an AA6060 alloy with a low-alloy 16MnCr5 filler steel. The influences of the setting parameters on the energetic states are first analyzed by means of an initial screening. The evaluation using process simulation and statistical methods enables the generation of regressive response surfaces for the friction power, the friction time and the resulting induced friction energy. Based on these findings, a second experimental field is formed and evaluated, which considers the interaction between the energy input of the frictioning stage and the workpiece forging. This new approach results in the functional separation of the frictioning and forging stage, which eliminates the usual statistical interaction effects and thus facilitates analysis and optimization. The qualitative result variable required for the purpose of interpreting the results is the ultimate tensile strength of the friction-welded joint. Additionally determined hardness curves provide information about the properties of the thermally influenced zone and strength-relevant process sequences. The result is that, in addition to the amount of energy induced, the frictional power with which the former is induced also has a considerable influence on the joint strength, as it influences the material flow and the properties of the joining zone.</p></div>","PeriodicalId":34313,"journal":{"name":"Journal of Advanced Joining Processes","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666330924000670/pdfft?md5=68ec14bd4d9234f6c5d6a20de1f68bbd&pid=1-s2.0-S2666330924000670-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142167346","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fe/polymer joining via Fe/TiB2 composite structures via in-situ laser-induced reaction of Fe-Ti-B system: Effect of powder composition","authors":"","doi":"10.1016/j.jajp.2024.100249","DOIUrl":"10.1016/j.jajp.2024.100249","url":null,"abstract":"<div><p>Achieving strong direct joining between steel and polymers through mechanical interlocking is crucial for developing multi-material structures, particularly in the automotive and aerospace industries. This study synthesized micro-scale structures on a pure Fe substrate (simulating interstitial-free (IF) steel) for mechanical interlocking with thermoplastic parts. Numerous submillimeter-scale Fe/TiB₂ composite particles were in-situ synthesized by laser scanning on the Fe-Ti-B powder mixture and well-bonded with the Fe substrate. The effects of powder composition (TiB₂ volume fraction) on the morphology, microstructure, and joint strength with PA6 were investigated. A TiB₂ volume fraction over 60 % was essential for the formation of the composite particles promoted by a TiB₂ skeletal structure. Higher TiB₂ volume fractions increased the area fraction of the composite particles and decreased the bonding ratio (adhesive) of the particles with the substrate due to poor adhesiveness at the edge of the laser-scanning line. A wider high-temperature region was generated at a higher TiB₂ volume fraction, suggesting that the reaction heat to form TiB₂ assisted the bonding of the particles with the substrate at the edge of the laser scanning line. The Fe/PA6 joint strength increased to approximately 30 MPa with increasing the TiB₂ volume fraction to 100 % and showed a linear correlation with the product of particle area fraction and bonding ratio. A higher TiB₂ volume fraction was preferable for enhancing the joint strength via the micro-scale structures synthesized by laser scanning on the Fe-Ti-B powder mixture. A combination of the micro-structuring process using a high fraction of TiB₂ with advanced joining technologies will contribute to manufacturing high-strength Fe/polymer hybrid parts.</p></div>","PeriodicalId":34313,"journal":{"name":"Journal of Advanced Joining Processes","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666330924000657/pdfft?md5=53be598e789d8f527444022129922e10&pid=1-s2.0-S2666330924000657-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142151888","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Interfacial inhomogeneous plastic deformation during rotary friction welding of dissimilar AA2219-SS321 joint combination with AA6061 interlayer","authors":"","doi":"10.1016/j.jajp.2024.100245","DOIUrl":"10.1016/j.jajp.2024.100245","url":null,"abstract":"<div><p>This research investigates the inherent radial non-uniformity within the rotary friction welding process, particularly concerning microstructure attributes like grain size, grain boundaries, misorientation angles, and interlayer presence along the radial axis. SS321-AA2219 rotary friction welding was carried out with and without an AA6061 interlayer. The numerical thermal model suggests increase in temperatures from the center to the periphery, due to non-uniform heat generation. Also, dissimilar material across the interface resulted in an asymmetric temperature profile along axial direction. Plastic deformation on the Aluminum side suggests dynamic recrystallization and grain refinement, whereas pronounced low-angle grain boundary (LAGB) formation near the SS side interface validates dynamic recovery. A radial non-uniformity in microstructure is observed, with metrics such as average grain size, LAGB fraction, and misorientation showing an increase from the center towards the periphery. The insertion of an interlayer alters process dynamics, manifesting in reduced temperatures and heightened forces, resulting in a more consolidated joint by enhancing the strength by 31 %. Interdiffusion of elements across the interface formed Fe-Al intermetallic compounds (IMC) confirmed with X ray diffraction. Fractography analysis elucidates the presence of rubbing marks and facet surfaces in interlayer-less joints, while joints with interlayer display sticking and dimples.</p></div>","PeriodicalId":34313,"journal":{"name":"Journal of Advanced Joining Processes","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S266633092400061X/pdfft?md5=449a36bd2bf29ba4780431b636df7c85&pid=1-s2.0-S266633092400061X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142096133","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Loosening phenomenon on thin plates bolted joint due to offset load","authors":"","doi":"10.1016/j.jajp.2024.100247","DOIUrl":"10.1016/j.jajp.2024.100247","url":null,"abstract":"<div><p>In this study, the new loosening behavior was discovered and investigated when offset loads were repeatedly applied to both ends of a bolted joint initially tightened to a thin plate made of high-tensile steel. In the experiments, the impact of offset distance on reduction of clamp force was investigated through multiple applications of symmetric offset axial load to the bolted joint assembly. The experimental results showed that even a slight offset load reduced the clamp force, and the larger the offset distance, the greater the reduction of the clamp force. It was also found that the decrease in clamp force depends not on the number of times the offset load is applied but on the magnitude of the offset load. Until now even if the thin plate bolted joint was subjected to an offset load, as long the plates do not deform significantly due to plastic deformation, it has been generally recognized that the clamp force is not reduced. This loosening phenomenon is new and its mechanism has not been elucidated yet. In order to clarify the mechanism that may lower the clamp force, this study conducted FE analysis using a simplified model of a bolted joint. In the FE model, the bolt and nut are considered as a single unit and the effect of slippage between the thread surfaces and the effect of plastic deformation is ignored by using elastic analysis. The results of the FE analysis showed that the main factor causing the reduction in clamp force was slippage between the thin plates to be joined, which was caused by offset load, and that the slippage didn't return to the original position resulting in the reduction in clamp force.</p></div>","PeriodicalId":34313,"journal":{"name":"Journal of Advanced Joining Processes","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666330924000633/pdfft?md5=003ec95187e4c76c2e1311bb8b75939d&pid=1-s2.0-S2666330924000633-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142122858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Friction weldability of ultrafine-grained titanium grade 2","authors":"","doi":"10.1016/j.jajp.2024.100246","DOIUrl":"10.1016/j.jajp.2024.100246","url":null,"abstract":"<div><p>The paper presents the results of an experimental study of the friction weldability of Titanium Grade 2 with ultrafine-grained (UFG) microstructure obtained by hydrostatic extrusion and rotary swaging (HE+RS). High-speed friction welding with different rotational speed (<em>n</em>) values was used as a joining method. The best properties were obtained for <em>n</em>=7000 rpm. Metallographic observations confirmed the formation of a continuous friction joint with a changed microstructure of the base material in the thermal-mechanical affected zone (TMAZ) and a friction weld (FW). The results of the mechanical properties showed the greatest decrease in hardness in the TMAZ. The friction welded joint had an 18 % lower tensile strength value than initial state UFG Titanium Grade 2 after the HE+RS process (with UTS=1050 MPa).</p></div>","PeriodicalId":34313,"journal":{"name":"Journal of Advanced Joining Processes","volume":null,"pages":null},"PeriodicalIF":3.8,"publicationDate":"2024-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666330924000621/pdfft?md5=b28c8deec0f62e706bc0fd10cfcaed21&pid=1-s2.0-S2666330924000621-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142095962","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}