发布求助
文献互助 智能选刊 最新文献

Fatigue & Fracture of Engineering Materials & Structures最新文献

筛选
英文 中文
Fatigue life prediction of additively manufactured AlSi10Mg based on surface roughness and residual stress 基于表面粗糙度和残余应力的铝硅镁复合材料疲劳寿命预测
IF 3.1 2区 材料科学
Fatigue & Fracture of Engineering Materials & Structures Pub Date : 2024-09-10 DOI: 10.1111/ffe.14441
Lea Strauß, Genny A. Pang, Günther Löwisch
{"title":"Fatigue life prediction of additively manufactured AlSi10Mg based on surface roughness and residual stress","authors":"Lea Strauß,&nbsp;Genny A. Pang,&nbsp;Günther Löwisch","doi":"10.1111/ffe.14441","DOIUrl":"https://doi.org/10.1111/ffe.14441","url":null,"abstract":"<p>Laser-based powder bed fusion (PBF-LB) has gained prominence in the realm of additive manufacturing of metals. This technique utilizes a laser beam to consolidate powder layers, which inherently introduces high thermal gradients and rapid cooling rates. This results in characteristic process effects, including inhomogeneities, surface roughness, anisotropy, and residual stress, which play a pivotal role in altering the fatigue properties of the manufactured components. This paper presents fatigue tests involving samples of AlSi10Mg manufactured using PBF-LB with varying surface roughness and residual stress. An approach to predict fatigue life based on stress amplitude, residual stress, and crack size is presented, using a smooth sample as a reference. An empirical model for fatigue life prediction is developed from experimentally measured values of fatigue life, peak surface roughness, and residual stress.</p>","PeriodicalId":12298,"journal":{"name":"Fatigue & Fracture of Engineering Materials & Structures","volume":"47 12","pages":"4465-4477"},"PeriodicalIF":3.1,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/ffe.14441","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142664761","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Fatigue crack initiation site transition of high-strength steel under very high-cycle fatigue 超高循环疲劳下高强度钢的疲劳裂纹起始点转换
IF 3.1 2区 材料科学
Fatigue & Fracture of Engineering Materials & Structures Pub Date : 2024-09-08 DOI: 10.1111/ffe.14437
Xiaoyuan Teng, Jianchao Pang, Chong Gao, Shouxin Li, Zhefeng Zhang
{"title":"Fatigue crack initiation site transition of high-strength steel under very high-cycle fatigue","authors":"Xiaoyuan Teng,&nbsp;Jianchao Pang,&nbsp;Chong Gao,&nbsp;Shouxin Li,&nbsp;Zhefeng Zhang","doi":"10.1111/ffe.14437","DOIUrl":"https://doi.org/10.1111/ffe.14437","url":null,"abstract":"<p>The very high-cycle fatigue (VHCF) fractographies of high-strength steel AISI 4340 with tensile strength ranging from 1285 to 2363 MPa fabricated by tempering were systematically observed and quantitatively analyzed. It is found that the fatigue crack initiation sites were gradually transferred from the specimen surface to the interior with increasing the tensile strength or decreasing the stress amplitude. Such phenomenon has become common rule in the high-cycle fatigue (HCF) or VHCF regimes of high-strength steels. Based on the fracture mechanics, a simplified transition mechanism for fatigue crack initiation sites is established in terms of the influence of applied stress amplitude and microstructure, which is beneficial to enhance our understanding on the variation of fatigue strength increasing the tensile strength.</p>","PeriodicalId":12298,"journal":{"name":"Fatigue & Fracture of Engineering Materials & Structures","volume":"47 12","pages":"4450-4464"},"PeriodicalIF":3.1,"publicationDate":"2024-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142664893","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Corrosion fatigue crack growth model for aluminum alloys in jet fuel 喷气燃料中铝合金的腐蚀疲劳裂纹增长模型
IF 3.1 2区 材料科学
Fatigue & Fracture of Engineering Materials & Structures Pub Date : 2024-09-04 DOI: 10.1111/ffe.14438
Zuoting Liu, Shilong Liu, Jing Cao, Yang Pan, Weixing Yao
{"title":"Corrosion fatigue crack growth model for aluminum alloys in jet fuel","authors":"Zuoting Liu,&nbsp;Shilong Liu,&nbsp;Jing Cao,&nbsp;Yang Pan,&nbsp;Weixing Yao","doi":"10.1111/ffe.14438","DOIUrl":"https://doi.org/10.1111/ffe.14438","url":null,"abstract":"<p>Aluminum alloys are primary structural materials in aircraft fuel systems, where jet fuel can influence the fatigue crack growth (FCG) behavior of materials. This paper presents a model for calculating the FCG rate of aluminum alloys in jet fuel environment. The model is based on elastoplastic fracture mechanics and revises the interaction terms in the linear superposition model by accounting for the corrosive environment and the crack closure effect. The derivation process of the model is discussed in detail. To validate the efficacy of the model, FCG tests were conducted on three types of aviation aluminum alloys, namely, 2524-T3, 7050-T7451, and 7075-T62 in the jet fuel. The experimental results were compared with FCG rates in the laboratory air environment. Findings indicate that the proposed model effectively captures the primary trends observed in the experimental data. In addition, the failure surfaces of the specimens were observed using a super-depth-of-field optical microscopy system.</p>","PeriodicalId":12298,"journal":{"name":"Fatigue & Fracture of Engineering Materials & Structures","volume":"47 12","pages":"4432-4449"},"PeriodicalIF":3.1,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142664595","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","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 fracture modes and acoustic emission characteristics of low-frequency disturbed coal rock bodies with different cyclic amplitudes 不同周期振幅的低频扰动煤岩体的断裂模式和声发射特性分析
IF 3.1 2区 材料科学
Fatigue & Fracture of Engineering Materials & Structures Pub Date : 2024-09-02 DOI: 10.1111/ffe.14434
Bin Liang, Dong Wang, Yujing Jiang, Hengjie Luan, Jiankang Liu, Jianlong Wang
{"title":"Analysis of fracture modes and acoustic emission characteristics of low-frequency disturbed coal rock bodies with different cyclic amplitudes","authors":"Bin Liang,&nbsp;Dong Wang,&nbsp;Yujing Jiang,&nbsp;Hengjie Luan,&nbsp;Jiankang Liu,&nbsp;Jianlong Wang","doi":"10.1111/ffe.14434","DOIUrl":"https://doi.org/10.1111/ffe.14434","url":null,"abstract":"<p>Frequent mining operations significantly disturb the security of deep weakly cemented rock roadways in western mining areas, constituting one of the primary causes of deformation, instability, and failure within the coal-rock body. In this paper, dynamic uniaxial compression tests of soft rock-coal combinations under low-frequency disturbance with different cyclic amplitudes were conducted based on acoustic emission to elucidate fracture modes. The findings are as follows: Different cycle amplitudes manifested significant degradation effects on the soft rock-coal combination. With increasing cycle amplitude, the proportion of tensile cracks initially decreased before subsequently increasing, demonstrating a general upward trajectory. The sudden increase in the acoustic emission RA value, the large decrease in the b-value, and AE counts reaching the peak mean that failure and destabilization of the specimen begin to occur. The results of this study will furnish theoretical direction for dynamic disaster monitoring and early warning in soft rock mines located in western mining regions.</p>","PeriodicalId":12298,"journal":{"name":"Fatigue & Fracture of Engineering Materials & Structures","volume":"47 12","pages":"4412-4431"},"PeriodicalIF":3.1,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142664557","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
A phase-field framework for stress corrosion cracking prediction in elastoplastic metallic materials 弹塑性金属材料应力腐蚀开裂预测的相场框架
IF 3.1 2区 材料科学
Fatigue & Fracture of Engineering Materials & Structures Pub Date : 2024-09-02 DOI: 10.1111/ffe.14428
Yuan-Zuo Wang, Zi-Han Liu, Lu Yang, Xiu-Li Du
{"title":"A phase-field framework for stress corrosion cracking prediction in elastoplastic metallic materials","authors":"Yuan-Zuo Wang,&nbsp;Zi-Han Liu,&nbsp;Lu Yang,&nbsp;Xiu-Li Du","doi":"10.1111/ffe.14428","DOIUrl":"https://doi.org/10.1111/ffe.14428","url":null,"abstract":"<p>To capture the stress corrosion cracking (SCC) in metallic materials, a phase-field framework considering localized plastic deformation and stress states is established. A new function of critical energy release rate is proposed to describe the degradation of cracking resistance of materials in the SCC process. This proposed framework can reproduce SCC results consistent with experimental observations in C-ring steel SCC tests, especially capturing the directionally characteristic of the cracks. Furthermore, the influences of localized plastic deformation and stress states on the SCC process are studied. This novel phase-field framework can capture (1) the influences of coupled electricity, mechanics to the SCC mechanisms; (2) the contribution of plastic strain energy as the driving force for the phase-field; (3) the potential and preferential crack initiation and propagation morphology within the complex stress and strain domain; and (4) the dependence of SCC rate and propagation direction on stress state and localized plastic deformation.</p>","PeriodicalId":12298,"journal":{"name":"Fatigue & Fracture of Engineering Materials & Structures","volume":"47 12","pages":"4393-4411"},"PeriodicalIF":3.1,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142664556","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Parametric characterization of the Christopher–James–Patterson model for crack propagation in welded zone of A7N01 Aluminum alloys 克里斯托弗-詹姆斯-帕特森模型对 A7N01 铝合金焊接区裂纹扩展的参数特性分析
IF 3.1 2区 材料科学
Fatigue & Fracture of Engineering Materials & Structures Pub Date : 2024-09-01 DOI: 10.1111/ffe.14423
Xi Liu, Yaohui Lu, Qiushi Wang, Chuan Lu, Neil James
{"title":"Parametric characterization of the Christopher–James–Patterson model for crack propagation in welded zone of A7N01 Aluminum alloys","authors":"Xi Liu,&nbsp;Yaohui Lu,&nbsp;Qiushi Wang,&nbsp;Chuan Lu,&nbsp;Neil James","doi":"10.1111/ffe.14423","DOIUrl":"https://doi.org/10.1111/ffe.14423","url":null,"abstract":"<p>Aluminum alloy is a widely used material in railway vehicle structures. In order to accurately analyze the crack propagation mechanism of Aluminum alloy welding structures and predict their crack propagation life, this study focuses on the A7N01 Aluminum alloy and proposes a full-field strain solution method based on the least-squares method. For the first time, digital image correlation (DIC) experimental measurements are combined with the finite element analysis method to determine the shape and size of the plastic zone at the crack tip of the compact tension (CT) specimen. And it also calculates the crack propagation driving force parameters of the Christopher–James–Patterson (CJP) model using traditional crack propagation driving parameters. The research results revealed that the plastic zone at the crack tip captured by DIC experiments is in good agreement with the finite element simulation results. Additionally, the crack growth rate curve of the A7N01 Aluminum alloy, fitted based on the CJP model, is insensitive to the stress ratio. The results offer an effective approach to utilizing the d<i>a</i>/d<i>N</i>-∆<i>K</i><sub>CJP</sub> curve in analyzing A7N01 Aluminum alloy and welded structural failures, broadening the scope of engineering applications for the CJP model.</p>","PeriodicalId":12298,"journal":{"name":"Fatigue & Fracture of Engineering Materials & Structures","volume":"47 11","pages":"4326-4340"},"PeriodicalIF":3.1,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142429159","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Corrosion fatigue cracking behaviors of Q690qE high-strength bridge steel as a weld joint in simulated marine environment 模拟海洋环境中作为焊接接头的 Q690qE 高强度桥梁钢的腐蚀疲劳开裂行为
IF 3.1 2区 材料科学
Fatigue & Fracture of Engineering Materials & Structures Pub Date : 2024-09-01 DOI: 10.1111/ffe.14427
Cuiping Lu, Qiong Yao, Ningning Li, Liyang Sun, Wenhe Dai, Chuang Zhang, Hongchi Ma
{"title":"Corrosion fatigue cracking behaviors of Q690qE high-strength bridge steel as a weld joint in simulated marine environment","authors":"Cuiping Lu,&nbsp;Qiong Yao,&nbsp;Ningning Li,&nbsp;Liyang Sun,&nbsp;Wenhe Dai,&nbsp;Chuang Zhang,&nbsp;Hongchi Ma","doi":"10.1111/ffe.14427","DOIUrl":"https://doi.org/10.1111/ffe.14427","url":null,"abstract":"<p>Corrosion fatigue behavior and mechanism of the weld joint of Q690qE high-strength bridge steel was investigated in a simulated marine environment. It reveals the sub-critical heat-affected zone (SCHAZ) and coarse-grained heat-affected zone (CGHAZ) are the most vulnerable sites to corrosion fatigue cracking. The CGHAZ of the Q690qE steel weld joint was prone to corrosion fatigue initiation mainly because of micro-galvanic corrosion between CGHAZ and weld metal (WM). The corrosion fatigue failure in SCHAZ mainly resulted from local stress/strain concentration due to weld softening. The final fracture location was determined by the competition between these two effects.</p>","PeriodicalId":12298,"journal":{"name":"Fatigue & Fracture of Engineering Materials & Structures","volume":"47 11","pages":"4341-4355"},"PeriodicalIF":3.1,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142429160","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Singularity analysis for V-notches in a piezoelectric multimaterial and functionally graded piezoelectric materials 压电多材料和功能分级压电材料中 V 形缺口的奇异性分析
IF 3.1 2区 材料科学
Fatigue & Fracture of Engineering Materials & Structures Pub Date : 2024-08-31 DOI: 10.1111/ffe.14424
Shanlong Yao, Guibin Dai, Changzheng Cheng, Zhongrong Niu
{"title":"Singularity analysis for V-notches in a piezoelectric multimaterial and functionally graded piezoelectric materials","authors":"Shanlong Yao,&nbsp;Guibin Dai,&nbsp;Changzheng Cheng,&nbsp;Zhongrong Niu","doi":"10.1111/ffe.14424","DOIUrl":"https://doi.org/10.1111/ffe.14424","url":null,"abstract":"<p>This study develops a novel singularity analysis method that addresses the limitations posed by piezoelectric material quantity and the variation patterns of property functions in functionally graded piezoelectric materials (FGPMs). Given that piezoelectric composite materials consist of multiple materials, the material properties of FGPMs vary with respect to angle. By introducing the asymptotic assumption that governs the physical fields close to the notch vertex into the static equilibrium equations, a comprehensive set of characteristic equations is formulated. All singularity orders and corresponding characteristic angle functions of the notch are determined by numerically solving the established characteristic equations. The effects of the notch opening angle, piezoelectric material polarization direction, and boundary conditions on the electromechanical field singularity at the notch are assessed. The judicious selection of material variation patterns can alleviate notch singularity in FGPMs.</p>","PeriodicalId":12298,"journal":{"name":"Fatigue & Fracture of Engineering Materials & Structures","volume":"47 11","pages":"4311-4325"},"PeriodicalIF":3.1,"publicationDate":"2024-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142430303","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Effects of thickness debit and stress concentration on superalloy DZ125 subjected to cyclic loading 厚度脱位和应力集中对承受循环加载的超级合金 DZ125 的影响
IF 3.1 2区 材料科学
Fatigue & Fracture of Engineering Materials & Structures Pub Date : 2024-08-30 DOI: 10.1111/ffe.14435
Yang Gan, Qinzheng Yang, Yi Zhao, Xiaoan Hu
{"title":"Effects of thickness debit and stress concentration on superalloy DZ125 subjected to cyclic loading","authors":"Yang Gan,&nbsp;Qinzheng Yang,&nbsp;Yi Zhao,&nbsp;Xiaoan Hu","doi":"10.1111/ffe.14435","DOIUrl":"https://doi.org/10.1111/ffe.14435","url":null,"abstract":"<p>In this paper, the thickness debit and stress concentration effects of a nickel-based directionally solidified superalloy were investigated through strain-controlled low cycle fatigue (LCF) and creep–fatigue interaction (CFI) experiments. Compared to the fatigue lives of solid specimens provided in the existing literature, the results of this paper indicate that when the wall thickness of the specimen is reduced from 5 to 1.125 mm, the fatigue life with different strain amplitudes decreases by about 45%. When film-cooling holes (FCHs) are introduced into the hollow specimens, the fatigue life is further reduced by about 25%. Based on the observation of the scanning electron microscope (SEM), the formation mechanisms of the thickness debit and stress concentration effects under LCF and CFI loads were revealed. Subsequently, two parameters, the “wall-thickness coefficient” and “hole coefficient,” were proposed to establish a new fatigue life prediction method.</p>","PeriodicalId":12298,"journal":{"name":"Fatigue & Fracture of Engineering Materials & Structures","volume":"47 11","pages":"4292-4310"},"PeriodicalIF":3.1,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142430284","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
A spot weld element formulation and implementation for mesh-insensitive fatigue evaluation of lightweight structures 用于轻质结构网格不敏感疲劳评估的点焊元件配方与实施
IF 3.1 2区 材料科学
Fatigue & Fracture of Engineering Materials & Structures Pub Date : 2024-08-29 DOI: 10.1111/ffe.14431
Lunyu Zhang, Shengjia Wu, Pingsha Dong
{"title":"A spot weld element formulation and implementation for mesh-insensitive fatigue evaluation of lightweight structures","authors":"Lunyu Zhang,&nbsp;Shengjia Wu,&nbsp;Pingsha Dong","doi":"10.1111/ffe.14431","DOIUrl":"https://doi.org/10.1111/ffe.14431","url":null,"abstract":"<p>With the rising importance of virtual engineering in an increasingly competitive marketplace, there is a growing need for simplified representations of finite element (FE) modeling for spot joints in lightweight structures without losing accuracy in structural life evaluation. For this purpose, this paper presents a spot weld element with an implicit weld representation and its numerical implementation as a user element for deployment in commercial FE code for reliably computing traction structural stress in a mesh-insensitive manner. The spot weld element is formulated by degenerating conventional first-order four-nodes shell elements by imposing kinematic constraints with respect to a series of virtual nodes placed in the region around a spot weld. The simplicity and effectiveness of the spot weld element have been validated by comparing with the explicit weld representation for computing mesh-insensitive structural stresses and fatigue life correlation of welded components.</p>","PeriodicalId":12298,"journal":{"name":"Fatigue & Fracture of Engineering Materials & Structures","volume":"47 11","pages":"4248-4268"},"PeriodicalIF":3.1,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142430282","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
首页 上一页 下一页 尾页
0
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
提示
您的信息不完整，为了账户安全，请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
现在去查看 取消
×
提示
确定
请完成安全验证×
相关产品
×
本文献相关产品
联系我们：info@booksci.cn Book学术提供免费学术资源搜索服务，方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。 Copyright © 2023 布克学术 All rights reserved.
京ICP备2023020795号-1
ghs 京公网安备 11010802042870号
Book学术文献互助
Book学术文献互助群
群 号：481959085
Book学术官方微信