Journal of Manufacturing and Materials Processing最新文献

Assessing the Feasibility of Fabricating Thermoplastic Laminates from Unidirectional Tapes in Open Mold Environments 评估在开放式模具环境中利用单向带制造热塑性层压板的可行性

IF 3.2

Journal of Manufacturing and Materials Processing Pub Date : 2024-01-06 DOI: 10.3390/jmmp8010012

Basit Ali, Khaled Kadri, M. Alkhader, W. Abuzaid, Mohammad A. Jaradat, Mohammed Mustafa, Mohamed Hassanien

{"title":"Assessing the Feasibility of Fabricating Thermoplastic Laminates from Unidirectional Tapes in Open Mold Environments","authors":"Basit Ali, Khaled Kadri, M. Alkhader, W. Abuzaid, Mohammad A. Jaradat, Mohammed Mustafa, Mohamed Hassanien","doi":"10.3390/jmmp8010012","DOIUrl":"https://doi.org/10.3390/jmmp8010012","url":null,"abstract":"The automation of the manufacturing processes of thermoplastic composite laminates has become dependent on open mold processes such as automated tape placement (ATP), which couples tape layering with in situ consolidation. The manufacturing parameters of ATP open mold processes, which comprise processing time, consolidation pressure and temperature, affect the bond strength between the plies and the quality of the laminates produced. Therefore, the effect of the manufacturing parameters should be characterized. This work experimentally evaluates the feasibility of fabricating thermoplastic laminates using an open mold process that reasonably models that of ATP. Glass fiber-reinforced polypropylene laminates are fabricated from unidirectional tapes under different consolidation periods, pressures, and temperatures. The bond quality in the produced laminates is assessed by measuring their interlaminar shear strength, which is measured using a short beam standardized shear test in conjunction with digital image correlation. Results show that consolidation can occur at temperatures slightly below the composite tapes’ complete melting temperature, and consolidation times between 7 and 13 min can result in acceptable bond strengths. The results confirmed the feasibility of the process and highlighted its limitations. Analysis of variance and machine learning showed that the effect of process parameters on interlaminar shear strength is nonlinear.","PeriodicalId":16319,"journal":{"name":"Journal of Manufacturing and Materials Processing","volume":"63 16","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139448982","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}

引用次数: 0

Vickers Hardness Mechanical Models and Thermoplastic Polymer Injection-Molded Products’ Static Friction Coefficients 维氏硬度力学模型和热塑性聚合物注塑产品的静摩擦系数

IF 3.2

Journal of Manufacturing and Materials Processing Pub Date : 2024-01-05 DOI: 10.3390/jmmp8010011

Tetsuo Takayama

引用次数: 0

Phase Composition, Microstructure and Mechanical Properties of Zr57Cu15Ni10Nb5 Alloy Obtained by Selective Laser Melting 通过选择性激光熔化获得的 Zr57Cu15Ni10Nb5 合金的相组成、显微结构和力学性能

IF 3.2

Journal of Manufacturing and Materials Processing Pub Date : 2024-01-04 DOI: 10.3390/jmmp8010010

R. Khmyrov, A. Korotkov, M. Gridnev, P. Podrabinnik, Tatiana V. Tarasova, Andrey V. Gusarov

{"title":"Phase Composition, Microstructure and Mechanical Properties of Zr57Cu15Ni10Nb5 Alloy Obtained by Selective Laser Melting","authors":"R. Khmyrov, A. Korotkov, M. Gridnev, P. Podrabinnik, Tatiana V. Tarasova, Andrey V. Gusarov","doi":"10.3390/jmmp8010010","DOIUrl":"https://doi.org/10.3390/jmmp8010010","url":null,"abstract":"Zr57Cu15Ni10Nb5 (more known as Vit-106) is a promising zirconium-based alloy with a high glass-forming ability, and belongs to the so-called bulk metallic glasses (BMG). Workpieces with a size of around one centimeter in all three dimensions can be obtained from a BMG alloy by casting. However, further increasing the cast size decreases the cooling rate and thus induces crystallization. Selective laser melting (SLM) is a well-known technique to overcome size limitations for BMGs because a workpiece is built by the addition of multiple melt portions in which the cooling rate is kept above the critical one. Currently, BMG parts obtained by SLM suffer from partial crystallization. The present work studies the influence of SLM process parameters on the partial crystallization of Vit-106 by metallography and the influence of the microstructure on mechanical properties by microhardness and wear resistance testing. Submicron crystalline inclusions are observed in an amorphous matrix of a Vit-106 alloy obtained by SLM. The size and the concentration of the inclusions can be controlled by varying the laser scanning speed. It is shown that submicron crystalline inclusions formed in the amorphous matrix during SLM can favorably affect microhardness and wear resistance.","PeriodicalId":16319,"journal":{"name":"Journal of Manufacturing and Materials Processing","volume":"58 3","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139387248","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}

引用次数: 0

In-Process Machining Distortion Prediction Method Based on Bulk Residual Stresses Estimation from Reduced Layer Removal 基于减层去除的块状残余应力估算的序中加工变形预测方法

IF 3.2

Journal of Manufacturing and Materials Processing Pub Date : 2024-01-03 DOI: 10.3390/jmmp8010009

M. Aurrekoetxea, Luis Norberto López de Lacalle, O. Zelaieta, I. Llanos

{"title":"In-Process Machining Distortion Prediction Method Based on Bulk Residual Stresses Estimation from Reduced Layer Removal","authors":"M. Aurrekoetxea, Luis Norberto López de Lacalle, O. Zelaieta, I. Llanos","doi":"10.3390/jmmp8010009","DOIUrl":"https://doi.org/10.3390/jmmp8010009","url":null,"abstract":"Manufacturing structural monolithic components for the aerospace market often involves machining distortion, which entails high costs and material and energy waste in industry. Despite the development of distortion calculation and avoidance tools, this issue remains unsolved due to the difficulties in accurately and economically measuring the residual stresses of the machining blanks. In the last years, the on-machine layer removal method has shown its potential for industrial implementation, offering the possibility to obtain final components from blanks with measured residual stresses. However, this measuring method requires too long an implementation time to be used in-process as part of the manufacturing chains. In this sense, the objective of this paper is to provide a machining distortion prediction method based on bulk residual stress estimation and hybrid modelling. The bulk residual stresses estimation is performed using reduced layer removal measurements. Considering bulk residual stress data and machining-induced residual stress data, as well as geometry and material data, real-part distortion calculations can be performed. For this, a hybrid model based on the combination of an analytical formulation and finite element modelling is employed, which enables us to perform fast and accurate calculations. With the developments here presented, the machining distortion can be predicted, and its uncertainty range can be calculated, in a simple and fast way. The accuracy and practicality of these developments are evaluated by comparison with the experimental results, showing the capability of the proposed solution in providing distortion predictions with errors lower than 10% in comparison with the experimental results.","PeriodicalId":16319,"journal":{"name":"Journal of Manufacturing and Materials Processing","volume":"46 14","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139451880","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}

引用次数: 0

Mesoscale Simulation of Laser Powder Bed Fusion with an Increased Layer Thickness for AlSi10Mg Alloy 增加层厚的 AlSi10Mg 合金激光粉末床熔化中尺度模拟

IF 3.2

Journal of Manufacturing and Materials Processing Pub Date : 2024-01-01 DOI: 10.3390/jmmp8010007

Maria Bogdanova, S. Chernyshikhin, Andrey Zakirov, B. Zotov, Leonid Fedorenko, Sergei Belousov, A. Perepelkina, Boris Korneev, Maria Lyange, Ivan Pelevin, Inna Iskandarova, Ella Dzidziguri, Boris Potapkin, Alexander Gromov

{"title":"Mesoscale Simulation of Laser Powder Bed Fusion with an Increased Layer Thickness for AlSi10Mg Alloy","authors":"Maria Bogdanova, S. Chernyshikhin, Andrey Zakirov, B. Zotov, Leonid Fedorenko, Sergei Belousov, A. Perepelkina, Boris Korneev, Maria Lyange, Ivan Pelevin, Inna Iskandarova, Ella Dzidziguri, Boris Potapkin, Alexander Gromov","doi":"10.3390/jmmp8010007","DOIUrl":"https://doi.org/10.3390/jmmp8010007","url":null,"abstract":"Low performance is considered one of the main drawbacks of laser powder bed fusion (LPBF) technology. In the present work, the effect of the AlSi10Mg powder layer thickness on the laser melting process was investigated to improve the LPBF building rate. A high-fidelity simulation of the melt pool formation was performed for different thicknesses of the powder bed using the Kintech Simulation Software for Additive Manufacturing (KiSSAM, version cd8e01d) developed by the authors. The powder bed after the recoating operation was obtained by the discrete element method. The laser energy deposition on the powder particles and the substrate was simulated by ray tracing. For the validation of the model, an experimental analysis of single tracks was performed on two types of substrates. The first substrate was manufactured directly with LPBF technology, while the second was cast. The simulation was carried out for various combinations of process parameters, predominantly with a high energy input, which provided a sufficient remelting depth. The calculations revealed the unstable keyhole mode appearance associated with the low absorptivity of the aluminum alloy at a scanning speed of 300 mm/s for all levels of the laser power (325–375 W). The results allowed formulating the criteria for the lack of fusion emerging during LPBF with an increased layer thickness. This work is expected to provide a scientific basis for the analysis of the maximum layer thickness via simulation to increase the performance of the technology.","PeriodicalId":16319,"journal":{"name":"Journal of Manufacturing and Materials Processing","volume":"56 11","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139126847","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}

引用次数: 0

Quality Prediction and Classification of Process Parameterization for Multi-Material Jetting by Means of Computer Vision and Machine Learning 利用计算机视觉和机器学习对多材料喷射工艺参数化进行质量预测和分类

IF 3.2

Journal of Manufacturing and Materials Processing Pub Date : 2024-01-01 DOI: 10.3390/jmmp8010008

Armin Reckert, Valentin Lang, Steven Weingarten, Robert Johne, Jan-Hendrik Klein, Steffen Ihlenfeldt

{"title":"Quality Prediction and Classification of Process Parameterization for Multi-Material Jetting by Means of Computer Vision and Machine Learning","authors":"Armin Reckert, Valentin Lang, Steven Weingarten, Robert Johne, Jan-Hendrik Klein, Steffen Ihlenfeldt","doi":"10.3390/jmmp8010008","DOIUrl":"https://doi.org/10.3390/jmmp8010008","url":null,"abstract":"Multi-Material Jetting (MMJ) is an additive manufacturing process empowering the printing of ceramics and hard metals with the highest precision. Given great advantages, it also poses challenges in ensuring the repeatability of part quality due to an inherent broader choice of built strategies. The addition of advanced quality assurance methods can therefore benefit the repeatability of part quality for widespread adoption. In particular, quality defects caused by improperly configured droplet overlap parameterizations, despite droplets themselves being well parameterized, constitute a major challenge for stable process control. This publication deals with the automated classification of the adequacy of process parameterization on green parts based on in-line surface measurements and their processing with machine learning methods, in particular the training of convolutional neural networks. To generate the training data, a demo part structure with eight layers was printed with different overlap settings, scanned, and labeled by process engineers. In particular, models with two convolutional layers and a pooling size of (6, 6) appeared to yield the best accuracies. Models trained only with images of the first layer and without the infill edge obtained validation accuracies of 90%. Consequently, an arbitrary section of the first layer is sufficient to deliver a prediction about the quality of the subsequently printed layers.","PeriodicalId":16319,"journal":{"name":"Journal of Manufacturing and Materials Processing","volume":"49 24","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139125489","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}

引用次数: 0

A Combined Microscopy Study of the Microstructural Evolution of Ferritic Stainless Steel upon Deep Drawing: The Role of Alloy Composition 铁素体不锈钢深拉时微结构演变的组合显微镜研究：合金成分的作用

IF 3.2

Journal of Manufacturing and Materials Processing Pub Date : 2024-01-01 DOI: 10.3390/jmmp8010006

A. Núñez, I. Collado, M. de la Mata, Juan F. Almagro, David L. Sales

{"title":"A Combined Microscopy Study of the Microstructural Evolution of Ferritic Stainless Steel upon Deep Drawing: The Role of Alloy Composition","authors":"A. Núñez, I. Collado, M. de la Mata, Juan F. Almagro, David L. Sales","doi":"10.3390/jmmp8010006","DOIUrl":"https://doi.org/10.3390/jmmp8010006","url":null,"abstract":"Ferritic stainless steel (FSS) is widely used to manufacture deep-drawn products for corrosion resistance applications, being the alloy drawability strongly affected by its microstructural anisotropy. This study combines a variety of microscopy techniques enabling in-depth analyses of the microstructural evolution of two different FSSs correlated to their deep drawing performance. One of the steels has a good correspondence with the standard EN-1.4016 (AISI 430). The other is a modified version of the previous one with higher contents of the ferrite-stabilising elements Si and Cr, and lower contents of the austenite-stabilising elements C, N, and Mn. Electron Backscatter Diffraction results confirm that the microstructural properties and drawability of FSS in the deep drawing process are improved in the modified steel version. Scanning transmission electron microscopy under low-angle annular dark field conditions evidences that the deformation mechanism of FSS during deep drawing follows a microstructural distortion model based on the grain size gradient and shows a variation of the deformation texture depending on the alloy composition. This work demonstrates the potential of advanced microscopy techniques for optimising the processing and design of ferritic stainless steels, with slight variations in the alloy composition, for deep drawing applications.","PeriodicalId":16319,"journal":{"name":"Journal of Manufacturing and Materials Processing","volume":"52 7","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139125210","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}

引用次数: 0

Analysis of Machinability on Properties of Inconel 718 Wire and Arc Additive Manufacturing Products 可加工性对铬镍铁合金 718 线材和电弧增材制造产品性能的影响分析

IF 3.2

Journal of Manufacturing and Materials Processing Pub Date : 2023-12-25 DOI: 10.3390/jmmp8010004

Gustavo Quadra Vieira dos Santos, Jun’ichi Kaneko, Takeyuki Abe

{"title":"Analysis of Machinability on Properties of Inconel 718 Wire and Arc Additive Manufacturing Products","authors":"Gustavo Quadra Vieira dos Santos, Jun’ichi Kaneko, Takeyuki Abe","doi":"10.3390/jmmp8010004","DOIUrl":"https://doi.org/10.3390/jmmp8010004","url":null,"abstract":"Wire and arc additive manufacturing (WAAM) is a metal deposition technique with a fast rate and the possibility of a high volume of deposition. Because of its fast deposition and high heat input, the manufactured products have poor surface quality. This paper presents a study on the machining of Inconel 718 wall-shaped additive manufacturing (AM) products, a necessary step for the improvement of surface quality. Considering the possibility that the characteristics of the milling processes of AM products might differ from those of traditionally manufactured parts, in this research, two types of Inconel 718 were studied and compared: one was manufactured using WAAM, and the other was an Inconel 718 rolled bar (Aerospace Material Specifications 5662). Using the testing procedure, a conventional two-flute cutting tool was used to assess their machinability. For this process, multiple passes were performed at three different heights of the samples. Considering the peculiarities of the AM products, such as their uneven surfaces, dendritic microstructures, and anisotropy, the results were analyzed. After the machining operation, the effects on the products were also studied by analyzing their surface quality. This study found a higher stability in the cutting process for the AMS 5662 samples relative to the WAAM parts with less variability in the cutting forces overall, resulting in better surface quality.","PeriodicalId":16319,"journal":{"name":"Journal of Manufacturing and Materials Processing","volume":"11 2","pages":""},"PeriodicalIF":3.2,"publicationDate":"2023-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139157701","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}

引用次数: 0

Numerical Modelling for Efficient Analysis of Large Size Multi-Stage Incremental Sheet Forming 用于高效分析大型多级增量板材成型的数值模型

IF 3.2

Journal of Manufacturing and Materials Processing Pub Date : 2023-12-22 DOI: 10.3390/jmmp8010003

Yehia A. Abdel-Nasser, Ninshu Ma, Sherif Rashed, Kenji Miyamoto, Hirotaka Miwa

{"title":"Numerical Modelling for Efficient Analysis of Large Size Multi-Stage Incremental Sheet Forming","authors":"Yehia A. Abdel-Nasser, Ninshu Ma, Sherif Rashed, Kenji Miyamoto, Hirotaka Miwa","doi":"10.3390/jmmp8010003","DOIUrl":"https://doi.org/10.3390/jmmp8010003","url":null,"abstract":"Incremental sheet forming (ISF) is an advanced flexible manufacturing process to produce complex 3D products. Unlike the conventional stamping process, ISF does not require any high cost dedicated dies. However, numerical computation for large-size ISF processes is time-consuming, and its accuracy for spring back due to unclamping tools after ISF cannot satisfy industrial demand. In this paper, an advanced numerical model considering complicated forming tool paths, trimming, and spring back was developed to efficiently simulate the multi-stage deformation phenomena of incremental sheet forming processes. Numerical modeling accuracy and efficiency are investigated considering the influence of tool path, material properties of the blank, mesh size, and boundary conditions. Through a series of case studies and comparisons with experimental results, it is observed that the numerical model with kinematics material properties and a moderate element size (5 mm) may reproduce the deformation characteristics of ISF with good accuracy and can obtain practical efficiency for a large-size ISF part.","PeriodicalId":16319,"journal":{"name":"Journal of Manufacturing and Materials Processing","volume":"21 4","pages":""},"PeriodicalIF":3.2,"publicationDate":"2023-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138946093","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}

引用次数: 0

Three-Dimensional Printing of Biomass–Fungi Biocomposite Materials: The Effects of Mixing and Printing Parameters on Fungal Growth 生物质-真菌生物复合材料的三维印刷：混合和印刷参数对真菌生长的影响

IF 3.2

Journal of Manufacturing and Materials Processing Pub Date : 2023-12-19 DOI: 10.3390/jmmp8010002

Al Mazedur Rahman, A. Bhardwaj, Joseph G. Vasselli, Zhijian Pei, Brian D. Shaw

{"title":"Three-Dimensional Printing of Biomass–Fungi Biocomposite Materials: The Effects of Mixing and Printing Parameters on Fungal Growth","authors":"Al Mazedur Rahman, A. Bhardwaj, Joseph G. Vasselli, Zhijian Pei, Brian D. Shaw","doi":"10.3390/jmmp8010002","DOIUrl":"https://doi.org/10.3390/jmmp8010002","url":null,"abstract":"Biomass–fungi biocomposite materials are derived from sustainable sources and can biodegrade at the end of their service. They can be used to manufacture products that are traditionally made from petroleum-based plastics. There are potential applications for these products in the packaging, furniture, and construction industries. In the biomass–fungi biocomposite materials, the biomass particles (made from agricultural waste such as hemp hurd) act as the substrate, and a network of fungal hyphae grow through and bind the biomass particles together. Typically, molding-based methods are used to manufacture products using these biocomposite materials. Recently, the authors reported a novel extrusion-based 3D printing method using these biocomposite materials. This paper reports a follow-up investigation into the effects of mixing parameters (mixing time and mixing mode) on fungal growth in biomass–fungi mixtures prepared for 3D printing and the effects of printing parameters (printing speed and extrusion pressure) on fungal growth in printed samples. The fungal growth was quantified using the number of fungal colonies that grew from samples. The results show that, when mixing time increased from 15 to 120 s, there was a 52% increase in fungal growth. Changing from continuous to intermittent mixing mode resulted in an 11% increase in fungal growth. Compared to mixtures that were not subjected to printing, samples printed with a high printing speed and high extrusion pressure had a 14.6% reduction in fungal growth, while those with a low printing speed and low extrusion pressure resulted in a 16.5% reduction in fungal growth.","PeriodicalId":16319,"journal":{"name":"Journal of Manufacturing and Materials Processing","volume":" 32","pages":""},"PeriodicalIF":3.2,"publicationDate":"2023-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138960855","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}

引用次数: 0