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A Coupled Thermomechanical Crack Propagation Behavior of Brittle Materials by Peridynamic Differential Operator

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Computer Modeling in Engineering & Sciences 2024年第7期140卷 339-361页

作者： tianyi li Xin Gu Qing Zhang College of Architectural Engineering Jiangsu Open UniversityNanjing210036China Department of Engineering Mechanics Hohai UniversityNanjing211100China

This study proposes a comprehensive,coupled thermomechanical model that replaces local spatial derivatives in classical differential thermomechanical equations with nonlocal integral forms derived from the peridynamic differential operator(PDDO),eliminating the need for calibration *** model employs a multi-rate explicit time integration scheme to handle varying time scales in multi-physics *** simulations conducted on granite and ceramic materials,this model demonstrates its *** successfully simulates thermal damage behavior in granite arising from incompatible mineral expansion and accurately calculates thermal crack propagation in ceramic slabs during *** account for material heterogeneity,the model utilizes the Shuffle algorithm andWeibull distribution,yielding results that align with numerical simulations and experimental *** coupled thermomechanical model shows great promise for analyzing intricate thermomechanical phenomena in brittle materials.

关键词： Peridynamic differential operator thermomechanical coupling heterogeneity numerical simulation

Simulation-based study of wind-wave interactions under various sea conditions

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Journal of Hydrodynamics 2019年第6期31卷 1148-1152页

作者： Xuanting Hao tianyi li Tao Cao lian Shen Department of Mechanical Engineering and Saint Anthony Falls Laboratory University of MinnesotaMinneapolisMinnesotaUSA

Despite their importance in the ocean environment,the key physical processes in wind-wave interactions are poorly *** a solver developed for undulatory boundaries,we perform numerical simulations of the wind-wave system under various sea conditions,including wind over monochromatic waves,early wind-wave generation,and wind over a broadband wave *** results show that the wave direction and wave age can significantly change the distribution of streamwise vorticity in the wind *** wave patterns are observed in the process of wind-wave *** a broadband wave field,the wave growth rate due to wind input is found to depend on the wave steepness.

关键词： Wind-wave interaction direct numerical simulation large eddy simulation phase-resolved wave simulation

Remediation of 2,4-dichlorophenol-contaminated groundwater using nano-sized CaO_(2)in a two-dimensional scale tank

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Frontiers of Environmental Science & Engineering 2021年第5期15卷 123-132页

作者： tianyi li Chengwu Zhang Jingyi Zhang Song Yan Chuanyu Qin Key Laboratory of Groundwater Resources and Environment(Ministry of Education) Jilin UniversityChangchun130021China Jilin Provincial Key Laboratory of Water Resources and Environment Jilin UniversityChangchun130021China National and Local Joint Engineering Laboratory for Petrochemical Contaminated Site Control and Remediation Technology Jilin UniversityChangchun130021China

This study evaluates the applicability of nano-sized calcium peroxide(CaO_(2))as a source of H_(2)O_(2)to remediate 2,4-dichlorophenol(2,4-DCP)contaminated groundwater via the advanced oxidation process(AOP).First,the effect and mechanism of 2,4-DCP degradation by CaO_(2)at different Fe concentrations were studied(Fenton reaction).We found that at high Fe concentrations,2,4-DCP almost completely degrades via primarily the oxidation of·OH within 5 *** low Fe concentrations,the degradation rate of 2,4-DCP decreased *** main mechanism was the combined action of·OH and O_(2)^(·−).Without Fe,the 2,4-DCP degradation reached 13.6%in 213 h,primarily via the heterogeneous reaction on the surface of CaO_(2).Besides,2,4-DCP degradation was significantly affected by solution *** the solution pH was>10,the degradation was almost completely ***,we adopted a two-dimensional water tank experiment to study the remediation efficiency CaO_(2)on the water *** noticed that the degradation took place mainly in regions of pH<10(i.e.,CaO_(2)distribution area),both upstream and downstream of the *** 28 days of treatment,the average 2,4-DCP degradation level was≈36.5%.Given the inadequacy of the results,we recommend that groundwater remediation using nano CaO_(2):(1)a buffer solution should be added to retard the rapid increase in pH,and(2)the nano CaO_(2)should be injected copiously in batches to reduce CaO_(2)deposition.

关键词： Calcium peroxide 2,4-DCP Reaction zone Fenton reaction

Climatologic comparison of HadISST1 and TMI sea surface temperature datasets

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Science China Earth Sciences 2011年第8期54卷 1238-1247页

作者： WANG Yu liU Peng li tianyi FU YunFei Laboratory of Atmospheric Observation and Climatological Environment School of Earth and Space Sciences University of Science and Technology of China Hefei 230026 China

Two monthly datasets of sea surface temperature (SST),TMI SST retrieved from satellite observations by Remote Sensing System and HadISST1 (Hadley Centre Sea-ice and Sea-surface Temperature Data Set Version 1) derived from in situ measurements by Hadley Centre,were compared on climatologic multiple time scales over tropical and subtropical areas from 1998 to *** indicate that there is a good consistency in the horizontal global distribution,with 1.0° resolution on multi-year and multi-season mean scales between the two datasets,and also in the time series of global mean SST ***,there are still some significant differences between the ***,TMI SST is relatively higher than *** addition,the differences between the two datasets show not only remarkable regionality,but also distinct seasonal ***,the maximum departure occurs in summer,while theminimum takes place in *** all seasons,over 30% of the regions in the Tropical and Subtropical areas have a difference of more than 0.3°*** analysis of the SST anomaly field also shows that there are differences between the two datasets,where HadISST1 has more significant statistical characteristics than TMI *** the other hand,results show that the difference between the two datasets is related to the vertical structure of ocean temperatures,as well as other simultaneously retrieved parameters in TMI products,such as wind speed,water vapor,liquid cloud water and rain *** addition,large biases between HadISST1 and TMI SST are found in coastal regions,where TMI SST cannot be accurately retrieved because of polluted microwave signals.

关键词： sea surface temperature HadISST1 TMI EOF analysis

Coupled Digital Image Correlation and Peridynamics for Full-Field Deformation Measurement and Local Damage Prediction

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Computer Modeling in Engineering & Sciences 2019年第11期121卷 425-444页

作者： tianyi li Xin Gu Qing Zhang Dong Lei Department of Engineering Mechanics Hohai UniversityNanjingChina

Digital image correlation(DIC)measurement technique and peridynamics(PD)method have been applied in specific fields extensively owing to their respective advantages in obtaining full-field deformation and local failure of loaded materials and *** study provides a simple way to couple DIC measurements with PD simulations,which can circumvent the difficulties of DIC in dealing with discontinuous *** the failure analysis of a compact tension specimen of aluminum alloy and a static three-point bending concrete beam as examples,the DIC experimental system firstly measures the full-field displacements,and then the PD simulation is applied on potential damage regions determined according to the correlation coefficients,to track the micro-crack evolution and macro-crack *** results,the coupled DIC and PD approach can effectively measure the full-field displacement and the localized damage accumulation and crack propagation.

关键词： Digital image correlation peridynamics discontinuity damage

Digital Twin Empowered PV Power Prediction

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Journal of Modern Power Systems and Clean Energy 2024年第5期12卷 1472-1483页

作者： Xiaoyu Zhang Yushuai li tianyi li Yonghao Gui Qiuye Sun David Wenzhong Gao the School of Information Science and Engi neering Northeastern UniversityShenyang 110004China the Department of Informatics Universi ty of OsloOslo 0316mNorway the Department of Computer Science Aalborg UniversityAal borg 9220Denmark the Electrification and Energy Infrastructures Division Oak Ridge National LaboratoryOak RidgeTN 37830USA the Department of Electrical and Computer Engineering University of DenverDenverCO 80208USA

The accurate prediction of photovoltaic(PV)power generation is significant to ensure the economic and safe operation of power *** this end,the paper establishes a new digital twin(DT)empowered PV power prediction framework that is capable of ensuring reliable data transmission and employing the DT to achieve high accuracy of power *** this framework,considering potential data contamination in the collected PV data,a generative adversarial network is employed to restore the historical dataset,which offers a prerequisite to ensure accurate mapping from the physical space to the digital ***,a new DT-empowered PV power prediction method is ***,we model a DT that encompasses a digital physical model for reflecting the physical operation mechanism and a neural network model(i.e.,a parallel network of convolution and bidirectional long short-term memory model)for capturing the hidden spatiotemporal *** proposed method enables the use of the DT to take advantages of the digital physical model and the neural network model,resulting in enhanced prediction ***,a real dataset is conducted to assess the effectiveness of the proposed method.

关键词： Photovoltaic power prediction digital twin hybrid prediction data recovery

Flow structures, nonlinear inertial waves and energy transfer in rotating spheres

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Theoretical & Applied Mechanics Letters 2021年第6期11卷 380-390页

作者： tianyi li Minping Wan Shiyi Chen Guangdong Provincial Key Laboratory of Turbulence Research and Applications Department of Mechanics and Aerospace EngineeringSouthern University of Science and TechnologyShenzhen 518055China State Key Laboratory for Turbulence and Complex Systems College of EngineeringPeking UniversityBeijing 100871China Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou) Guangzhou 511458China

We investigate flow structures,nonlinear inertial waves and energy transfer in a rotating fluid sphere,using a Galerkin spectral method based on helical-wave decomposition(HWD).Numerical simulations of flows in a sphere are performed with different system rotation rates,where a large-scale forcing is *** the case without system rotation,the intense vortex structures are *** a weak rotation is introduced,small-scale structures are reduced and vortex tubes tend to align with the rotation *** the rotation rate increases,a large-scale anticyclonic vortex structure is formed near the rotation *** structure is shown to be led by certain geostrophic *** the rotation rate further increases,a cyclone and an anticyclone emerge from the top and bottom of the boundary,respectively,where two quasi-geostrophic equatorially symmetric inertial waves dominate the *** on HWD,effects of spherical confinement on rotating turbulence are systematically *** is found that the forward cascade becomes weaker as the rotation *** the rotation rate becomes larger than some critical value,dual energy cascades emerge,with an inverse cascade at large scales and a forward cascade at small ***,the flow behavior near the boundary is studied,where the average boundary layer thickness gets smaller when system rotation *** flow behavior in the boundary layer is closely related to the interior flow structures,which create significant mass flux between the boundary layer and the interior fluid through Ekman pumping.

关键词： Rotating turbulence Spherical confinement Helical-wave deomposition Inertial wave

Two-dimensional plane strain consolidation of unsaturated soils considering the depth-dependent stress

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Journal of Rock Mechanics and Geotechnical Engineering 2023年第6期15卷 1603-1614页

作者： Lei Wang Sidong Shen tianyi li Minjie Wen Annan Zhou School of Urban Railway Transportation Shanghai University of Engineering ScienceShanghai201620China Key Laboratory of Soft Soils and Geoenvironmental Engineering of Ministry of Education Zhejiang UniversityHangzhou310058China School of Civil Environmental and Chemical EngineeringRoyal Melbourne Institute of Technology(RMIT)MelbourneVIC3001Australia

In practical engineering,the total vertical stress in the soil layer is not constant due to stress diffusion,and varies with time and ***,the purpose of this paper is to investigate the effect of stress diffusion on the two-dimensional(2D)plane strain consolidation properties of unsaturated soils when the stress varies with time and depth.A series of semi-analytical solutions in terms of excess pore air and water pressures and settlement for 2D plane strain consolidation of unsaturated soils can be derived with the joint use of Laplace transform and Fourier sine series ***,the inverse Laplace transform of the semi-analytical solution is given in the time domain using a self-programmed code based on Crump’s *** reliability of the obtained solutions is proved by the ***,the 2D plots of excess pore pressures and the curves of settlement varying with time,considering different physical parameters of unsaturated soil stratum and depth-dependent stress,are depicted and analyzed to study the 2D plane strain consolidation properties of unsaturated soils subjected to the depthdependent stress.

关键词： Semi-analytical solutions Two-dimensional(2D)plane strain consolidation Unsaturated soils Depth-dependent stress Laplace transform

Thermal and hydrophobic properties of glycerol stearate-modified Pinus radiata wood

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Journal of Forestry Research 2019年第4期30卷 1521-1525页

作者： Jia Xu Bin li Tiqi Zhao tianyi li lili Wang College of Science Northeast Forestry University

Glycerol stearate was synthesized by esterification with non-toxic,inexpensive glycerol and stearic *** composite of glycerol stearate and Pinus radiata wood was prepared by vacuum *** Fourier transform infrared(FTIR)analysis,there was the generation of new C=O stretching vibration band of glycerol stearate in comparison with stearic *** confirms that glycerol stearate was successfully *** weight gain,FTIR spectrum and morphological analyses of the composite indicate that glycerol stearate was impregnated into the interior lumina of the *** analysis showed that the maximal degradation temperature of the composite was 42℃higher than untreated *** angle images indicated that the value of the composite was134.2°.Hydrophobicity(the repulsion of water)of the composite was stronger than glycerol stearate,which a large number of hydroxyl of wood reacted with the oxygen-containing groups of glycerol stearate,improved hydrophobicity and thermal stability,thereby enhancing the potential application of *** wood.

关键词： Wood composite Glycerol stearate Pinus radiata Hydrophobicity Thermal stability