Additive manufacturing最新文献

{"title":"Inhibition of interfacial cracks in 304L-Inconel718 bimetal fabricated via laser powder bed fusion","authors":"Yinghui Li ,&nbsp;Zhuangzhuang Liu ,&nbsp;Zhengyu Wei ,&nbsp;Pengfei Hu ,&nbsp;Jiawang Chen ,&nbsp;Lijing Liu ,&nbsp;Guogang Shu ,&nbsp;Jianxin Xie","doi":"10.1016/j.addma.2024.104463","DOIUrl":"10.1016/j.addma.2024.104463","url":null,"abstract":"<div><div>Multi-material additive manufacturing is crucial for intricate component fabrication, yet challenges, such as interfacial cracks and weak bonding, persist. This work investigated the laser powder bed fusion (L-PBF) of bimetallic components (stainless steel 304L-nickel-based alloy Inconel718) crucial in aerospace and nuclear applications. It is found that the interfacial cracks predominantly occur within the compositional transition zone where the proportion of 304 L is between 45 wt% and 75 wt%, characterized by brittle Laves phases along grain boundaries. Experimental and finite element simulations of melt pool reveal that a higher ratio of temperature gradient (<span><math><mover><mrow><mi>G</mi></mrow><mo>̅</mo></mover></math></span>) to the grain growth rate (<span><math><mover><mrow><mi>R</mi></mrow><mo>̅</mo></mover></math></span>) (<span><math><mover><mrow><mi>G</mi></mrow><mo>̅</mo></mover></math></span>/<span><math><mover><mrow><mi>R</mi></mrow><mo>̅</mo></mover></math></span>) results in straight grain boundaries with underdeveloped secondary dendrites. This leads to the formation of continuous liquid film and strip-like Laves phase at grain boundaries, causing interfacial cracks during L-PBF. To suppress these cracks, this work proposes manipulating grain boundaries into a tortuous morphology through promoting the growth of secondary dendrites. By controlling the <span><math><mover><mrow><mi>G</mi></mrow><mo>̅</mo></mover></math></span>/<span><math><mover><mrow><mi>R</mi></mrow><mo>̅</mo></mover></math></span> ratios below the critical value (&lt;147.9×10⁶ K∙s/m²) and combining with a high cooling rate (<span><math><mover><mrow><mi>G</mi></mrow><mo>̅</mo></mover></math></span>×<span><math><mover><mrow><mi>R</mi></mrow><mo>̅</mo></mover></math></span>) during L-PBF, a well-developed secondary dendritic structure and grain refinement are achieved, significantly enhancing grain boundary tortuosity and forming discretely distributed Laves phases. As a result, interfacial cracks are completely suppressed, enabling the successful manufacturing of crack-free 304L-Inconel718 bimetallic components. The approach of tailoring the distribution of brittle precipitates through manipulating grain boundary morphology proposed in this work provides a novel and practical pathway for inhibiting cracks in multi-material additive manufacturing.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"94 ","pages":"Article 104463"},"PeriodicalIF":10.3,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142423467","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A mechanical characteristic capture method considering printing configurations for buildability modeling in concrete 3D printing","authors":"Yuning Chen ,&nbsp;Kailun Xia ,&nbsp;Enlai Dong ,&nbsp;Ruilin Cao ,&nbsp;Yueyi Gao ,&nbsp;Yamei Zhang","doi":"10.1016/j.addma.2024.104462","DOIUrl":"10.1016/j.addma.2024.104462","url":null,"abstract":"<div><div>The structure failure modeling of 3D printing concrete (3DPC) during production is crucial for structure design, manufacturing process control and optimization. Serving as model inputs, the accuracy of 3DPC fresh material properties measurement highly affects the model prediction performance. The measured mechanical properties of freshly printed concrete strongly depend on the geometry, deformation and hardening process of used samples in testing. Herein, we propose an all-in-one method (AIOM) that synchronously considers these key factors (layer geometry, deformation, and hardening process) to more accurately capture the early-age mechanical performance distribution in printed structures. Different parametric-mechanical buckling models and two printable cementitious materials with distinct hardening characteristics (printable cement and printable geopolymer) were used to validate the performance of AIOM, with the traditional testing method, uniaxial unconfined compression test (UUCT), as the reference. Compared with UUCT, AIOM can improve the buildability prediction accuracy by 11.9 % to 50.8 % for different validation scenarios. This novel testing method for 3DPC fresh material properties contributes to improving the accuracy of 3DPC structure failure models, thereby facilitating a better production phase control for 3DPC.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"94 ","pages":"Article 104462"},"PeriodicalIF":10.3,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142423468","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Obtaining excellent mechanical properties with additively manufactured short fiber reinforced polyether-ether-ketone thermoplastics through simultaneous vacuum and infrared heating","authors":"Recep Gümrük ,&nbsp;Bahri Barış Vatandaş ,&nbsp;Altuğ Uşun","doi":"10.1016/j.addma.2024.104491","DOIUrl":"10.1016/j.addma.2024.104491","url":null,"abstract":"<div><div>Additive manufacturing of short fiber reinforced thermoplastic composite with high-performance engineering thermoplastics is important in various industrial sectors because of their ability to manufacture complex and lightweight products. Although extensive studies in the literature are aimed at enhancing the mechanical performance of additively manufactured short fiber reinforced thermoplastics through methods like refining printing parameters, enhancing fiber fractions, and optimizing printing parameters, their mechanical performance remains limited. In this study, the individual effects of vacuum-assisted printing and infrared pre-heater-assisted printing and their combined effects were investigated to substantially increase the mechanical properties, interlaminar performance, and crystallinity ratios. The polyether ether ketone (PEEK) samples were printed with vacuum-assisted, infrared-assisted, and a combination of vacuum and infrared-assisted environments were subjected to three-point bending tests to evaluate their mechanical properties. Synergistic vacuum and infrared-assisted printing significantly enhanced the mechanical properties as the flexural strength increased by 54.58 % compared to printing under vacuum alone. Moreover, the flexural strength and elasticity modulus of samples printed with vacuum-infrared-assisted manufacturing increased by 324.48 % and 239.77 %, respectively, when compared to printing under atmospheric pressure without additional heating. Thermal and structural characterizations of the printed parts revealed that this significant improvement was attributed to reduced porosity ratios and increased crystallinity.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"94 ","pages":"Article 104491"},"PeriodicalIF":10.3,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142533983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Near-surface microstructures convolute mechanical properties in additively manufactured metals","authors":"Kaitlynn M. Fitzgerald ,&nbsp;Jay D. Carroll ,&nbsp;Dale E. Cillessen ,&nbsp;Anthony Garland ,&nbsp;Timothy J. Ruggles ,&nbsp;Kyle L. Johnson ,&nbsp;Brad L. Boyce","doi":"10.1016/j.addma.2024.104477","DOIUrl":"10.1016/j.addma.2024.104477","url":null,"abstract":"<div><div>Kovar specimens were additively manufactured with 180 variations in process conditions. Three distinct geometries (two tensile geometries and a Charpy specimen) were evaluated for each set of process conditions. Tensile specimens additively manufactured to net shape had less porosity, more uniform material properties, higher average ductility, and they consistently failed via ductile rupture. Tensile specimens harvested via electric discharge machining from larger additively manufactured blocks often contained lack of fusion voids throughout the cross section - those pre-existing pores drove pre-mature failure. As-printed specimens, on the other hand, were more representative of the outer border properties rather than the interior of large printed parts. The properties of the specimens cut from the larger block of additively manufactured material were more representative of the inner hatch properties but were stochastic, depending on the size and location of present voids. Using a high-throughput methodology, the results from over 800 tensile tests are reported here. This extensive statistical sampling allows the effects of specimen type and location to be clearly distinguished from other intentional variables (process parameter variations) and stochastic material variability.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"94 ","pages":"Article 104477"},"PeriodicalIF":10.3,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142534041","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Data-driven reliability-oriented buildability analysis of 3D concrete printed curved wall","authors":"Baixi Chen,&nbsp;Xiaoping Qian","doi":"10.1016/j.addma.2024.104459","DOIUrl":"10.1016/j.addma.2024.104459","url":null,"abstract":"<div><div>The inherent uncertainties, particularly material uncertainties, significantly impact the buildability of 3D concrete-printed curved walls, leading to substantial variations that complicate quality control. To address this, a data-driven stochastic analysis framework is proposed for reliability-oriented buildability evaluation. Material uncertainties are quantified using a maximum likelihood-based stochastic parameter estimation method and considered as the uncertainty sources. Subsequently, a data-driven model, namely sparse Gaussian process regression (SGPR) model, is trained and combined with Monte Carlo simulation to assess the stochastic behavior of curved wall buildability. The influences of print speed, layer height, and horizontal curvature on buildability are analyzed under varying reliability levels. Additionally, an empirical model is proposed for the rapid evaluation of maximum buildability at specified horizontal curvature and reliability levels, providing significant practical value for 3D concrete printing designers. The impact of other uncertainty sources including the model error on reliability-oriented buildability is also discussed. These sources exhibit negligible influence when their intensities are less than 30 % of that caused by material uncertainty. Furthermore, the feasibility of the data-driven reliability-oriented buildability analysis for more complex geometry is also demonstrated.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"94 ","pages":"Article 104459"},"PeriodicalIF":10.3,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142358177","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Additive manufacturing of heterogeneous combinatorial functional surface by plasmonic hierarchical sintering of silicon particles for active manipulation of rheological liquid motion","authors":"Sung Jin Park,&nbsp;Seunghyun Back,&nbsp;Bongchul Kang","doi":"10.1016/j.addma.2024.104474","DOIUrl":"10.1016/j.addma.2024.104474","url":null,"abstract":"<div><div>We present a sustainable and efficient additive manufacturing method of silicon-based heterogeneous combinatorial functional surfaces designed to actively manipulate liquid droplet motion dynamics to address advanced rheological engineering challenges and applications. This additive manufacturing enables the instantaneous formation and control of hierarchical multiscale structures with tunable wettability through instantaneous plasmonic thermophysical sintering between laser and Si particles, eliminating the need for additional masks and subsequent processing steps. Furthermore, this fabrication approach can selectively implement heterogeneous combinatorial functional surfaces in a single domain by reversibly switching extreme wettability modes (e.g., from superhydrophobic to superhydrophilic) upon laser irradiation. Continuous superhydrophilic channels in a superhydrophobic background created by selective laser re-irradiation provide sufficient local attraction to manipulate droplet motion along the channel due to van der Waals forces and Laplace pressure fields generated by the difference in wettability. Active manipulation of droplet dynamic motion, such as trajectory tracking and antigravity self-propulsion, can be realized by simply designing a laser scanning path that determines the geometry of the local channel. The manipulation platform for liquid motion dynamics can be applied to active microfluidic channels with no cavity, without the need for an external power source. This advancement has important implications for broad fluid and rheological engineering applications.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"94 ","pages":"Article 104474"},"PeriodicalIF":10.3,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142434089","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mechanical properties of Ti-6Al-4V thin walls fabricated by laser powder bed fusion","authors":"Junghoon Lee ,&nbsp;Arif Hussain ,&nbsp;Jeonghong Ha ,&nbsp;Youngsam Kwon ,&nbsp;Rae Eon Kim ,&nbsp;Hyoung Seop Kim ,&nbsp;Dongsik Kim","doi":"10.1016/j.addma.2024.104484","DOIUrl":"10.1016/j.addma.2024.104484","url":null,"abstract":"<div><div>Laser powder bed fusion (PBF-LB/M) has recently garnered considerable attention for fabricating thin walls owing to its potential for producing lightweight structures. However, knowledge of the mechanical properties of thin walls with high surface-to-volume ratios remains insufficient. Specifically, no studies have been conducted for thin walls with a thickness less than 400 µm, making the size effect unclear. Therefore, the main objective of this work is to reveal the effect of thicknesses on the mechanical properties of Ti-6Al-4V samples as thin as 195 µm. To achieve this, the fabrication process was optimized to maximize the aspect ratio and properties of samples. In addition, the microstructure and surface roughness were examined to understand the size effect. The results demonstrated that the ultimate tensile strength of the thin-wall samples was similar to that of bulk Ti-6Al-4V samples fabricated via PBF-LB/M, regardless of the thickness. By contrast, the elongation of the thin-wall samples decreased with thickness, indicating a significant size effect. This size effect on elongation can be attributed to the strong influence of surface and internal defects.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"94 ","pages":"Article 104484"},"PeriodicalIF":10.3,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142533981","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Molten pool behaviors and printability of tungsten anti-scattering grids with extremely thin wall thickness fabricated via laser powder bed fusion","authors":"Meng Wang ,&nbsp;Changjun Han ,&nbsp;Menglong Jiang ,&nbsp;Vyacheslav Trofimov ,&nbsp;Yongqiang Yang ,&nbsp;Chao Yang ,&nbsp;Yongwei Feng ,&nbsp;Ming Yan ,&nbsp;Shaochong Wei ,&nbsp;Di Wang","doi":"10.1016/j.addma.2024.104487","DOIUrl":"10.1016/j.addma.2024.104487","url":null,"abstract":"<div><div>It is challenging for laser powder bed fusion (LPBF) technique to fabricate metal parts with a wall thickness below 100 μm. This work investigated the critical conditions for achieving extremely thin wall thickness in tungsten grids fabricated via LPBF. Specifically, the impact of low energy density on the printability of tungsten single tracks and grids via LPBF was comprehensively examined. A computational fluid dynamics approach was employed to develop a thermal fluid flow model for single tracks with multilayers in LPBF. The findings demonstrate that at low energy densities, single tracks exhibit four different morphologies, i.e., balling, discontinuity and winding, discontinuity but straightness, as well as continuity and straightness. The simulation model effectively elucidates the continuity of single tracks and provides insights into the governing mechanism of molten pool defects. Due to high thermal diffusion properties of tungsten, the continuity of its track relies on the connection of neighboring molten pools and is sensitive to scanning speed. The tungsten molten pools with low energy density can be categorized into shallow flows affected by surface morphology and deep flows influenced by internal voids of the powder bed. After multi-layer stacking, the track fluctuations and defects in single tracks accumulated into greater surface roughness and deteriorate thin-walled morphology. The critical conditions required for printing extremely thin walls were achieved, ensuring minimal merging of tracks between two layers by maintaining the energy density of 57 J/mm³. Based on these findings, an ultra-thin-walled anti-scattering tungsten grid with a wall thickness of 86 μm and a wall roughness below 3.3 μm (<em>Ra</em>) was fabricated by LPBF. This work provides valuable theoretical insights and presents a viable methodology for determining the minimum energy density threshold and wall thickness essential for LPBF processing of thin-walled components.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"94 ","pages":"Article 104487"},"PeriodicalIF":10.3,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142533987","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Solute and phase heterogeneous distribution at different scales and its effect on ageing physical phenomena in a laser powder bed fusion produced maraging steel","authors":"Ana Santana ,&nbsp;Adriana Eres-Castellanos ,&nbsp;Jonathan D. Poplawsky ,&nbsp;David San-Martin ,&nbsp;Jose Antonio Jimenez ,&nbsp;Esteban Urones-Garrote ,&nbsp;Amy J. Clarke ,&nbsp;Carlos Capdevila ,&nbsp;Francisca G. Caballero","doi":"10.1016/j.addma.2024.104494","DOIUrl":"10.1016/j.addma.2024.104494","url":null,"abstract":"<div><div>The Laser Powder Bed Fusion process involves complex thermodynamic and heat transfer mechanisms which results in a complicated understanding of the material’s microstructure and phase transformation processes. In the case of additive manufacturing maraging steels, these present heterogeneous structures which mainly consist of Body-Centred Tetragonal (BCT) martensite and retained austenite (Face-Centred Cubic (FCC) phase structure), unlike conventionally processed material. Research has already been done on the competitive or collaborative nature of austenite growth/reversion and precipitation in these materials. However, for Laser Powder Bed Fusion maraging steels, studies have focused on either the effect of the heterogeneous structures on austenite reversion kinetics or the formation, evolution and behaviour of precipitation. Still, no comprehensive research exists that covers in detail the relation between solute heterogeneity from the meso- to the nanoscale and its influence on both phase distribution and ageing physical phenomena. To do so, multiscale chemical analyses and microstructural characterisation techniques were used to investigate a maraging steel M300 in different transformed conditions: as-built, aged at 480 and 540 °C. The results showed that competing mechanisms during printing caused segregation at the mesoscale, which remains in aged samples. Vaporisation led to Cr segregation, while melt convections caused Ni and Ti depletion at melt pool boundaries. Retained austenite location was found at melt pool boundaries and away from them on the as-built structure. Its preferential location remains unclear. Dissimilarities from conventional material were identified in nanosized clustering and precipitates on aged samples.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"94 ","pages":"Article 104494"},"PeriodicalIF":10.3,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142533865","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimisation of microstructures from filament extrusion additive manufacturing based on numerical simulation with VOLCO-X","authors":"Rafael Quelho de Macedo ,&nbsp;Rafael Thiago Luiz Ferreira ,&nbsp;Andrew Gleadall ,&nbsp;Ian Ashcroft","doi":"10.1016/j.addma.2024.104430","DOIUrl":"10.1016/j.addma.2024.104430","url":null,"abstract":"<div><div>The mechanical properties of parts built with material extrusion additive manufacturing are highly dependent on the material distribution within parts’ microstructure. This varies with the choice of process parameters. Therefore, when designing a functional printed part, one must tailor the printing parameters in order to obtain the desired properties, such as minimal voids. The present work proposes an optimisation method that designs printing parameters to minimise manufacturing time while keeping the void volume fraction at very low values (hence improving mechanical properties), keeping dimensions within tight tolerances and guaranteeing structural integrity. The new optimisation method utilises the authors’ previously developed software VOLCO-X, which is capable of efficiently predicting material distribution from filament extrusion within printed parts, including print track dimensions and microstructure geometry, without the need for any experimental calibration. In order to validate the proposed optimisation scheme, optimised printed parts using the scheme and parts using printing parameters determined by a commercial slicing software were manufactured and compared for different printing speeds and deposition strategies. At printing speed of 16 mm/s, it was possible to decrease the manufacturing time by more than 20% and structural mass by more than 5% in comparison to the commercial slicer printed part, whilst maintaining similar mechanical properties. At printing speed of 96 mm/s, due to the high printing speed, the commercial printed part presented gap faults between deposited strands, while the optimised part had structural integrity. At this printing speed, the optimised printed part presented significant improvements in terms of mechanical properties. The proposed optimisation methodology, in conjunction with VOLCO-X, is a powerful tool that can be used to improve manufacturing by filament extrusion. This innovative tool allows the identification of printing parameters without experiments and trial-and-error approaches, thus saving time and expense.</div></div>","PeriodicalId":7172,"journal":{"name":"Additive manufacturing","volume":"94 ","pages":"Article 104430"},"PeriodicalIF":10.3,"publicationDate":"2024-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142328012","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}