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Improving fatigue properties of normal direction ultrasonic vibration assisted face grinding Inconel 718 by regulating machined surface integrity

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International Journal of Extreme Manufacturing 2024年第3期6卷 458-475页

作者： Nianwei Xu Renke kang Bi Zhang Yuan Zhang Chenxu Wang Yan Bao Zhigang Dong State Key Laboratory of High-Performance Precision Manufacturing Dalian University of TechnologyDalian 116024People’s Republic of China Department of Mechanical and Energy Engineering Southern University of Science and TechnologyShenzhen 518055People’s Republic of China

Fatigue properties are crucial for critical aero-engine components in extreme serviceenvironments,which are significantly affected by surface integrity(SI)indexes(especially surface topography,residual stressσ_(res),and microhardness)after machining ***-direction ultrasonic vibration-assisted face grinding(ND-UVAFG)has advantages in improving the machinability of Inconel 718,but there is a competitive relationship between higher compressiveσ_(res)and higher surface roughness R_(a)in affecting fatigue *** lack of a quantitative relationship between multiple SI indexes and fatigue strength makes theindeterminacy of a regulatory strategy for improving fatigue *** this work,a model of fatigue strength(σ_f)_(sur)considering multiple SI indexes was ***,high-cycle fatigue tests were carried out on Inconel 718 samples with different SI characteristics,and the influence of ND-UVAFG process parameters on SI was *** on SI indexes data,the(σ_f)_(sur)distribution in the grinding surface layer for ND-UVAFG Inconel 718 samples was determined using the developed model,and then the fatigue crack initiation(FCI)sites were *** predicted FCI sites corresponded well with the experimental results,therebyverifying this model.A strategy for improving the fatigue life was proposed in this work,which was to transfer the fatigue source from the machined surface to the bulk material by controlling the SI ***,a critical condition of SI indexes that FCI sites appeared on the surface or in bulk material was given by fitting the predicted *** to the critical condition,an SI field where FCI sites appeared in the bulk material could be *** this field,thefatigue life of Inconel 718 samples could be improved by approximately 140%.

关键词： surface integrity fatigue strength Inconel 718 ultrasonic assisted grinding

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In^(3+)-doped Sr_(2)Fe_(1.5)Mo_(0.5)O_(6−δ)cathode with improved performance for an intermediate-temperature solid oxide fuel cell

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Nano Research 2024年第1期17卷 407-415页

作者： Yumei Ma Lijie Zhang kang Zhu Binze Zhang Ranran Peng Changrong Xia Ling Huang State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources College of ChemistryXinjiang UniversityUrumqi 830046China Department of Materials Science and Engineering University of Science and Technology of ChinaHefei 230026China

Promoting the oxygen reduction reaction(ORR)is critical for commercialization of intermediate-temperature solid oxide fuel cells(IT-SOFCs),where Sr_(2)Fe_(1.5)Mo_(0.5)O_(6)−δ(SFM)is a promising cathode by working as a mixed ionic and electronic *** this work,doping of In^(3+)greatly increases the oxygen vacancy concentration and the content of adsorbed oxygen species in Sr_(2)Fe_(1.5)Mo_(0.5−x)InxO_(6−δ)(SFMInx),and thus effectively promotes the ORR *** a typical example,SFMIn_(0.1)reduces the polarization resistance(R_(p))from 0.089 to 0.046Ω∙cm^(2)at 800°C,which is superior to those doped with other metal *** addition,SFMIn0.1 increases the peak power density from 0.92 to 1.47 W∙cm^(−2)at 800°C with humidified H_(2)as the fuel,indicating that In3+doping at the Mo site can effectively improve the performance of SOFC cathode material.

关键词： solid oxide fuel cell cathode In3+doping oxygen reduction reaction(ORR) Sr_(2)Fe_(1.5)Mo_(0.5)O_(6-δ)

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Experimental and numerical study on protective effect of RC blast wall against air shock wave

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Defence Technology（防务技术） 2024年第1期31卷 567-579页

作者： Xin-zhe Nian Quan-min Xie Xin-li Kong Ying-kang Yao Kui Huang State Key Laboratory of Precision Blasting Jianghan UniversityWuhan430056China Hubei Key Laboratory of Blasting Engineering Jianghan UniversityWuhan430056China Hubei(Wuhan)Institute of Explosion and Blasting Technology Jianghan UniversityWuhan430056China College of Defense Engineering Army Engineering University of PLANanjing210007China Institute of Defense Engineering AMSPLALuoyang471023China

Prototype experiments were carried out on the explosion-proof performance of the RC blast *** mass of TNT detonated in the experiments is 5 kg and 20 kg *** shock wave overpressure was tested in different *** above experiments were numerically simulated,and the simulated shock wave overpressure waveforms were compared with that tested and given by CONWEP *** results show that the numerically simulated waveform is slightly different from the test waveform,but similar to CONWEP *** dimensional analysis and numerical simulation under different working conditions,the equation for the attenuation rate of the diffraction overpressure behind the blast wall was *** to the corresponding standards,the degree of casualties and the damage degree of the brick concrete building at a certain distance behind the wall can be determined when parameters are *** above results can provide a reference for the design and construction of the reinforced concrete blast wall.

关键词： Blast wall Shock wave Diffraction Overpressure Protection

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Swelling behaviors of heterogeneous red-bed mudstone subjected to different vertical stresses

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第5期16卷 1847-1863页

作者： kang Huang Zhangjun Dai Chengzeng Yan Fei Yu Wei Zhang Shanxiong Chen State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China University of Chinese Academy of Sciences Beijing100049China Faculty of Engineering China University of GeosciencesWuhanChina International Joint Research Center for Deep Earth Drilling and Resource Development China University of GeosciencesWuhan430074China

In this study,the axial swelling strain of red-bed mudstone under different vertical stresses are measured by swell-under-load method,and the microstructure of mudstone after hygroscopic swelling is studied by mercury intrusion porosimetry(MIP).The weakening coefficient and Weibull distribution function are introduced into the coupling model of mudstone moisture diffusion-swelling deformation-fracture based on finite-discrete element method(FDEM).The weakening effect of moisture on mudstone's mechanical parameters,as well as the heterogeneity of swelling deformation and stress distribution,is *** microcrack behavior and energy evolution of mudstone during hygroscopic swelling deformation under different vertical stresses are *** results show that the axial swelling strain of mudstone decreases with increase of the vertical *** low vertical stresses,moisture absorption in mudstone leads to formation of cracks caused by hydration-induced *** high vertical stresses,a muddy sealing zone forms on the mudstone surface,preventing further water *** simulation results of mudstone swelling deformation also demonstrate that it involves both swelling of the mudstone matrix and swelling caused by crack ***,crack expansion plays a dominant role in mudstone *** increasing vertical stress,the cracks in mudstone change from tensile cracks to shear cracks,resulting in a significant reduction in the total number of *** the evolution of mudstone kinetic energy shows similarities under different vertical stresses,the evolution of strain energy varies significantly due to the presence of different types of cracks in the *** findings provide a theoretical basis for understanding the hygroscopic swelling deformation mechanism of red-bed mudstone at various depths.

关键词： Heterogeneous red-bed mudstone Self-sealing band Matric swelling and crack expansion FDEM Microcracks Energy evolution

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Coupling and coordinated evolution characteristics of regional economy-energy-carbon emission multiple systems:A case study of main China's Basin

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Journal of Environmental Sciences 2024年第6期140卷 204-218页

作者： Lu Chen Xin Li Jingyi Zhao Xinyu kang Lu Liu Minxi Wang Wu Chen College of Management Science Chengdu University of TechnologyChengdu 610051China SDU Life Cycle Engineering Department of Green TechnologyUniversity of Southern Denmark5230 OdenseDenmark

Comprehensive analysis of the Economy-Energy-Carbon Emission(EECE)system is beneficial for promoting sustainable social *** study analyzes the system development of major watersheds in China from 2010 to *** research fully considers the system’s internal and external inputs and outputs and proposes an evaluation index system for regional EECE coupling and coordinated ***,using the difference in system weight allocation to improve the coupling and coordination model,the study explores the dynamic system’s coupling and *** results show that(1)The development of the system structure is relatively stable,but the overall development status is not ideal;(2)The downstream of China’s main river basins has obvious economic advantages,while the energy system fluctuates *** efficiency of the carbon emission system will decrease in areas with rapid economic *** coupling and coordination level of the EECE system is better in the Yangtze River Basin than in the Yellow River Basin;(3)From the perspective of dynamic coordinated development,the main river basins have been divided into two states since 2012,but it is relatively stable *** dynamic coordination is often at a disadvantage in regions with rapid economic and energy development;(4)The coupling coordination degree of the two river basins has significant positive spatial *** provinces’significant spatial clustering characteristics of the coupling coordination degree are High-High ***-Low type provinces are mainly concentrated *** research process has certain reference significance for the collaborative governance of complex regional systems.

关键词： System structure Efficiency measure Coupling mechanism Dynamic coordination

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First-principles study on the heterogeneous formation of environmentally persistent free radicals(EPFRs)overα-Fe2O3(0001)surface:Effect of oxygen vacancy

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Journal of Environmental Sciences 2024年第8期142卷 279-289页

作者： Wenxiao Pan Shuming He Qiao Xue Xian Liu Jianjie Fu kang Xiao Aiqian Zhang State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China School of Environment Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of SciencesHangzhou 310012China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China Beijing Yanshan Earth Critical Zone National Research Station University of Chinese Academy of SciencesBeijing 101408China

Metal oxides with oxygen vacancies have a significant impact on catalytic activity for the transformation of organic pollutants in waste-to-energy(WtE)incineration *** study aims to investigate the influence of hematite surface oxygen point defects on the formation of environmentally persistent free radicals(EPFRs)from phenolic compounds based on the first-principles *** oxygen-deficient conditions were considered:oxygen vacancies at the top surface and on the *** simulations indicate that the adsorption strength of phenol on theα-Fe_(2)O_(3)(0001)surface is enhanced by the presence of oxygen ***,the presence of oxygen vacancies has a negative impact on the dissociation of the phenol molecule,particularly for the surface with a defective point at the top ***-kinetic parameters were established over a temperature range of300-1000 K,and lower reaction rate constants were observed for the scission of phenolic O-H bonds over the oxygen-deficient surfaces compared to the pristine *** negative effects caused by the oxygen-deficient conditions could be attributed to the local reduction of FeⅢto FeⅡ,which lower the oxidizing ability of surface reaction *** findings of this study provide us a promising approach to regulate the formation of EPFRs.

关键词： EPFR formation Phenol dissociation Oxygen-vacancy impact Hematite surface First-principles calculation

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Mechanical behavior of rock under uniaxial tension:Insights from energy storage and dissipation

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第7期16卷 2466-2481页

作者： Guanshuang Tan Chunde Ma Junjie Zhang Wenyuan Yang Guiyin Zhang Zihao kang School of Resources and Safety Engineering Central South UniversityChangsha410083China

Many rock engineering projects show that the growth of tensile cracks is often an important cause of engineering disasters,and the mechanical behavior of rocks is essentially the transmission,storage,dissipation and release of *** investigate the tensile behavior of rock from the perspective of energy,uniaxial tension tests(UTTs)and uniaxial compression tests(UCTs)were carried out on three typical rocks(granite,sandstone and marble).Different unloading points were set before the peak stress to separate elastic energy and dissipated *** input energy density ut,elastic energy density ue,and dissipated energy density ud at each unloading point were calculated by integrating stress-strain *** results show that there is a strong linear relationship between the three energy parameters and the square of the unloading stress in UCT,but this linear relationship is weaker in *** ue and ud increase linearly with the increase in ut in UCT and *** on the phenomenon that ue and ud increase linearly with ut,the applicability of Wp et index in UTT was proved and the relative energy storage capacity and absolute energy distribution characteristics of three rocks in UCT and UTT were *** tensile behavior of marble and sandstone in UTT can be divided into two stages vaguely according to the energy distribution,but granite is not the *** addition,based on dissipated energy,the damage evolution of three types of rocks in UCT and UTT was *** study provides some new insights for understanding the tensile behavior of rock.

关键词： Uniaxial tension Energy density Mechanical behavior Energy storage coefficient Energy dissipation coefficient

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Micropillar compression using discrete dislocation dynamics and machine learning

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Theoretical & Applied Mechanics Letters 2024年第1期14卷 39-47页

作者： Jin Tao Dean Wei Junshi Yu Qianhua Kan Guozheng kang Xu Zhang School of Mechanics and Aerospace Engineering Southwest Jiaotong UniversityChengdu 610031China State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing 100190China

Discrete dislocation dynamics(DDD)simulations reveal the evolution of dislocation structures and the interaction of *** study investigated the compression behavior of single-crystal copper micropillars using fewshot machine learning with data provided by DDD *** types of features are considered:external features comprising specimen size and loading orientation and internal features involving dislocation source length,Schmid factor,the orientation of the most easily activated dislocations and their distance from the free *** yielding stress and stress-strain curves of single-crystal copper micropillar are predicted well by incorporating both external and internal features of the sample as separate or combined *** is found that the machine learning accuracy predictions for single-crystal micropillar compression can be improved by incorporating easily activated dislocation features with external ***,the effect of easily activated dislocation on yielding is less important compared to the effects of specimen size and Schmid factor which includes information of orientation but becomes more evident in small-sized ***,incorporating internal features,especially the information of most easily activated dislocations,improves predictive capabilities across diverse sample sizes and orientations.

关键词： Discrete dislocation dynamics simulations Machine learning Size effects Orientation effects Microstructural features

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Photo-induced tunable luminescence from an aggregated amphiphilic ethylene-pyrene derivative in aqueous media

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Chinese Chemical Letters 2024年第6期35卷 303-306页

作者： Junying Zhang Ruochen Li Haihua Wang Wenbing kang Xing-Dong Xu National Engineering Research Center for Colloidal Materials Key Laboratory of Special Functional Aggregated Materials of Ministry of EducationShandong Key Laboratory of Advanced Silicone Materials and TechnologySchool of Chemistry and Chemical EngineeringShandong UniversityJi’nan 250100China

An amphiphilic derivative with a large Stokes shift by introducing flexible hydrophilic long chains into a rigid ethylene-pyrene compound have been successfully *** alkylated compound exhibited a notable change in charge distribution,facilitating cation-π *** the process of amphiphilic self-assembly,the formation of highly ordered aggregates enabled effective photo-dimerization under 449 nm LED ***,this photo-responsive technology not only exhibited advanced multi-color emission effects,including white light emission but also exhibited environmentally friendly behavior in the aqueous phase.

关键词： Supramolecular chemistry Amphiphilic assembly Stimuli-responsive materials Tunable luminescence Pyrene derivative

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Unraveling engineering disturbance effects on deformation in red-bed mudstone railway cuttings:incorporating crack-facilitated moisture diffusion

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Journal of Mountain Science 2024年第5期21卷 1663-1682页

作者： HUANG kang DAI Zhangjun YAN Chengzeng YAO Junkai CHI Zecheng CHEN Shanxiong State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan 430071China University of Chinese Academy of Sciences Beijing 100049China Faculty of Engineering China University of GeosciencesWuhan 430074China International Joint Research Center for Deep Earth Drilling and Resource Development China University of GeosciencesWuhan 430074China China Academy of Railway Sciences Corporation Limited Beijing 100081China

Red-bed mudstone, prevalent in southwest China, poses a formidable challenge due to its hydrophilic clay minerals, resulting in expansion, deformation, and cracking upon exposure to moisture. This study addresses uplift deformation disasters in high-speed railways by employing a moisture diffusion-deformation-fracture coupling model based on the finite-discrete element method(FDEM). The model integrates the influence of cracks on moisture diffusion. The investigation into various excavation depths reveals a direct correlation between depth and the formation of tensile cracks at the bottom of the railway cutting. These cracks expedite moisture migration, significantly impacting the temporal and spatial evolution of the moisture field. Additionally, crack expansion dominates hygroscopic deformation, with the lateral coordinate of the crack zone determining peak vertical displacement. Furthermore, key factors influencing deformation in railway cuttings, including the swelling factor and initial moisture content at the bottom of the cutting, are explored. The number of tensile and shear cracks increases with greater excavation depth, particularly concerning shear cracks. Higher swelling factors and initial moisture contents result in an increased total number of cracks, predominantly shear cracks. Numerical calculations provide valuable insights, offering a scientific foundation and directional guidance for the precise prevention, control, prediction, and comprehensive treatment of mudstone-related issues in high-speed railways.

关键词： Red-bed mudstone Railway cutting FDEM Moisture diffusion Deformation Crack

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