检索结果-南通市图书馆

Modeling Reynolds stress anisotropy invariants via machine learning

Acta Mechanica Sinica 2024年第6期40卷 50-63页

作者： Xianglin Shan Xuxiang Sun Wenbo Cao Weiwei Zhang Zhenhua Xia School of Aeronautics Northwestern Polytechnical UniversityXi’an710072China department of engineering mechanics Zhejiang UniversityHangzhou310027China

The presentation and modeling of turbulence anisotropy are crucial for studying large-scale turbulence structures and constructing turbulence ***,accurately capturing anisotropic Reynolds stresses often relies on expensive direct numerical simulations(DNS).Recently,a hot topic in data-driven turbulence modeling is how to acquire accurate Reynolds stresses by the Reynolds-averaged Navier-Stokes(RANS)simulation and a limited amount of data from *** existing studies use mean flow characteristics as the input features of machine learning models to predict high-fidelity Reynolds stresses,but these approaches still lack robust generalization *** this paper,a deep neural network(DNN)is employed to build a model,mapping from tensor invariants of RANS mean flow features to the anisotropy invariants of high-fidelity Reynolds *** the aspects of tensor analysis and input-output feature design,we try to enhance the generalization of the model while preserving invariance.A functional framework of Reynolds stress anisotropy invariants is derived *** irreducible invariants are then constructed from a tensor group,serving as alternative input features for ***,we propose a feature selection method based on the Fourier transform of periodic *** results demonstrate that the data-driven model achieves a high level of accuracy in predicting turbulence anisotropy of flows over periodic hills and converging-diverging ***,the well-trained model exhibits strong generalization capabilities concerning various shapes and higher Reynolds *** approach can also provide valuable insights for feature selection and data generation for data-driven turbulence models.

关键词： Reynolds stress Anisotropy invariant Tensor analysis Machine learning

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

The influence of stress-dependent overpotential on dendrite growth in all-solid-state battery with cracks

引用

Science China(Technological Sciences) 2024年第8期67卷 2493-2504页

作者： ZHANG ZhenHua ZHANG Yong LIU Chang HOU Xu WANG Jie department of engineering mechanics School of Aeronautics and AstronauticsZhejiang UniversityHangzhou 310027China Zhejiang Laboratory Hangzhou 311100China Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province Zhejiang UniversityHangzhou 310027China School of Aerospace engineering and Applied mechanics Tongji UniversityShanghai 200092China Applied mechanics and Structure Safety Key Laboratory of Sichuan Province School of Mechanics and Aerospace EngineeringSouthwest Jiaotong UniversityChengdu 610031China department of Industrial and Systems engineering The Hong Kong Polytechnic UniversityHong Kong 999077China

Dendrite growth is one of the main challenges in maintaining the service life of all-solid-state lithium-ion *** stress has been reported to significantly affect dendrite *** this study,to explain the effect of mechanical stress on electrochemical reactions in all-solid-state batteries,a modified phase-field model for dendrite growth is proposed by considering the stress-dependent *** growth under different mechanical loadings in an all-solid-state battery is investigated using the proposed *** with previous experimental results,the current result shows that compressive stress inhibits dendrite *** the stress concentration at the tips of processing-induced microcracks,the effects of the number and distribution of microcracks on dendrite growth are *** results show that the stress-concentration field induced at the tips of cracks or voids can change the morphology of dendrites and decrease their growth *** study provides a new perspective for explaining Li dendrite growth under mechanical stress and offers inspiration for prolonging the service life of all-solid-state batteries based on defect and stress regulation,which may be further realized in experiments by filling solid electrolytes with different types of nanofillers.

关键词： Butler–Volmer equation stress-dependent overpotential microcracks all-solid-state battery phase-field simulation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Effect of boundary conditions on shakedown analysis of heterogeneous materials

引用

Applied Mathematics and mechanics(English Edition) 2024年第1期45卷 39-68页

作者： Xiuchen GONG Yinghao NIE Gengdong CHENG Kai LI State Key Laboratory of Structural Analysis Optimization and CAE Software for Industrial EquipmentInternational Research Center for Computational MechanicsDepartment of Engineering MechanicsDalian University of TechnologyDalian 116023Liaoning ProvinceChina

The determination of the ultimate load-bearing capacity of structures made of elastoplastic heterogeneous materials under varying loads is of great importance for engineering analysis and design. Therefore, it is necessary to accurately predict the shakedown domains of these materials. The static shakedown theorem, also known as Melan's theorem, is a fundamental method used to predict the shakedown domains of structures and materials. Within this method, a key aspect lies in the construction and application of an appropriate self-equilibrium stress field(SSF). In the structural shakedown analysis, the SSF is typically constructed by governing equations that satisfy no external force(NEF) boundary conditions. However, we discover that directly applying these governing equations is not suitable for the shakedown analysis of heterogeneous materials. Researchers must consider the requirements imposed by the Hill-Mandel condition for boundary conditions and the physical significance of representative volume elements(RVEs). This paper addresses this issue and demonstrates that the sizes of SSFs vary under different boundary conditions, such as uniform displacement boundary conditions(DBCs), uniform traction boundary conditions(TBCs), and periodic boundary conditions(PBCs). As a result, significant discrepancies arise in the predicted shakedown domain sizes of heterogeneous materials. Built on the demonstrated relationship between SSFs under different boundary conditions, this study explores the conservative relationships among different shakedown domains, and provides proof of the relationship between the elastic limit(EL) factors and the shakedown loading factors under the loading domain of two load vertices. By utilizing numerical examples, we highlight the conservatism present in certain results reported in the existing literature. Among the investigated boundary conditions, the obtained shakedown domain is the most conservative under ***, utilizing PBCs to

关键词： heterogeneous material self-equilibrium stress field(SSF) shakedown analysis effect of boundary conditions

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

In situ infrared, Raman and X-ray spectroscopy for the mechanistic understanding of hydrogen evolution reaction

引用

Journal of Energy Chemistry 2024年第3期90卷 632-651,I0014页

作者： Andi Haryanto Kyounghoon Jung Chan Woo Lee Dong-Wan Kim department of Chemistry Kookmin UniversitySeoul 02707Republic of Korea School of Civil Environmental and Architectural EngineeringKorea UniversitySeoul 02841Republic of Korea

Hydrogen production by water reduction reactions has received considerable attention because hydrogen is considered a clean-energy carrier,key for a sustainable energy *** methods have been widely used to study the reaction mechanism of the hydrogen evolution reaction(HER),but the calculation results need to be supported by experimental results and direct evidence to confirm the mechanistic *** this review,we discuss the fundamental principles of the in situ spectroscopic strategy and a theoretical model for a mechanistic understanding of the *** addition,we investigate recent studies by in situ Fourier transform infrared(FTIR),Raman spectroscopy,and X-ray absorption spectroscopy(XAS) and cover new findings that occur at the catalyst-electrolyte interface during *** spectroscopic strategies provide practical ways to elucidate catalyst phase,reaction intermediate,catalyst-electrolyte interface,intermediate binding energy,metal valency state,and coordination environment during HER.

关键词： Hydrogen evolution reaction Infrared spectroscopy Raman spectroscopy X-ray absorption spectroscopy Reaction mechanism

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Study on a semi-resolved CFD-DEM method for rod-like particles in a gas-solid fluidized bed

引用

Particuology 2024年第4期87卷 20-36页

作者： Liping He Zhengxian Liu Yongzhi Zhao department of mechanics School of Mechanical EngineeringTianjin UniversityTianjin300350China Insttute of Process quipment College of Energy EngineeringZhejiang UniversityHangzhou30027China

Based on a semi-resolved CFD-DEM coupling method,this study proposed a method that uses the minimum distance between the fluid grid and the particle boundary as a reference value to determine the degree of influence of the target fluid grid on the particle's drag force.A fluidized bed of rod-like particles was chosen as a typical case to investigate the effect of different fluid grid scales on various fluidized bed characteristic *** calculation performance of the semi-resolved and unre-solved CFD-DEM coupling algorithm on key fluidized bed characteristic parameters such as average pressure drop,particle frequency distribution with bed height,and particle orientation distribution were *** was found that the semi-resolved CFD-DEM coupling algorithm gradually obtained results with higher consistency with decreasing fluid grid scale for key parameters such as particle frequency distribution with bed height,particle orientation distribution,and time-history mixing index,exhibiting a phenomenon similar to grid independence in fluid *** comparing with experimental results,it was verified that the semi-resolved CFD-DEM coupling algorithm can be applied to simulate multi-granular gas-solid systems with fluid grid scales equivalent to particle *** algorithm solves the limitation of fluid grid scale in the unresolved CFD-DEM coupling framework and improves the grid adaptability of the CFD-DEM coupling simulation algorithm.

关键词： CFD-DEM Semi-resolved method Fluid-solid flow Non-spherical particle Fluidized bed

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Theoretical optimization of micropillar arrays for structurally stable bioinspired dry adhesives

引用

Theoretical & Applied mechanics Letters 2024年第2期14卷 124-129页

作者： Ke Ni Zhengzhi Wang department of engineering mechanics School of Civil EngineeringWuhan UniversityWuhan 430072China Wuhan University Shenzhen Research Institute Shenzhen 518108China

Inspired by the excellent adhesion performances of setae structure from organisms,micro/nano-pillar array has become one of the paradigms for adhesive *** micropillar arrays are composed of the resin pillars for adhesion and the substrate with different elastic modulus for *** stress singularity at the bi-material corner between the pillars and the substrate can induce the failure of the micropillar-substrate corner and further hinder the fabrication and application of micropillar arrays,yet the design for the stability of the micropillar array lacks systematical and quantitative *** this work,we develop a semi-analytical method to provide the full expressions for the stress distribution within the bi-material corner combining analytical derivations and numerical *** predictions for the stress within the singularity field can be obtained based on the full expressions of the *** good agreement between the predictions and the FEM results demonstrates the high reliability of our *** adopting the strain energy density factor approach,the stability of the pillar-substrate corner is assessed by predicting the failure at the *** the elastic mismatch between the pillar and substrate given in this paper,the stability can be improved by increasing the ratio of the shear modulus of the substrate to that of the *** study provides accurate predictions for the stress distribution at the bi-material corner and can guide the optimization of material combinations of the pillars and the substrate for more stable bioinspired dry adhesives.

关键词： Micropillar array Stability Bi-material corner Dry adhesive

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Velocity transformation for compressible wall-bounded turbulence——An approach through the mixing length hypothesis

引用

Science China(Physics,mechanics & Astronomy) 2024年第9期67卷 108-125页

作者： Xuke Zhu Yubin Song Xiaoshuo Yang Zhenhua Xia State Key Laboratory of Fluid Power and Mechatronic Systems and department of engineering mechanics Zhejiang UniversityHangzhou 310027China

In an endeavor to establish a connection between the mean velocity profile in compressible wall-bounded turbulence and its incompressible analogue,a refined version of the Trettel and Larsson's(TL)transformation is systematically derived and rigorously assessed across diverse flow *** the recently proposed intrinsic compressibility effects and modeling the multi-layer structure of mixing lengths,the proposed transformation demonstrates exceptional performance in collapsing 57canonical flow cases,including cooled channel and pipe flows,channel flows with pseudo heat sources,as well as adiabatic and diabatic boundary layer ***,the transformation seamlessly extends to low Reynolds number cooled channel and pipe flows,achieving a level of accuracy unparalleled by other transformations in the current state-of-the-art.

关键词： mixing length hypothesis compressible wall-bounded turbulence velocity transformation law of the wall

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Dynamic analysis of a novel multilink-spring mechanism for vibration isolation and energy harvesting

引用

Chinese Physics B 2024年第5期33卷 366-379页

作者：谢佳衡杨涛唐介 Research & Development Institute of Northwestern Polytechnical University in Shenzhen Shenzhen 518057China department of engineering mechanics Northwest Polytechnical UniversityXi'an 710072China Applied mechanics and Structure Safety Key Laboratory of Sichuan Province School of Mechanics and AerospaceSouthwest Jiaotong UniversityChengdu 610031China

Due to technical limitations,existing vibration isolation and energy harvesting(VIEH)devices have poor performance at low *** paper proposes a new multilink-spring mechanism(MLSM)that can be used to solve this *** VIEH performance of the MLSM under harmonic excitation and Gaussian white noise was *** was found that the MLSM has good vibration isolation performance for low-frequency isolation and the frequency band can be widened by adjusting parameters to achieve a higher energy harvesting *** comparison with two special cases,the results show that the MLSM is basically the same as the other two oscillators in terms of vibration isolation but has better energy harvesting performance under multistable *** MLSM is expected to reduce the impact of vibration on high-precision sensitive equipment in some special sites such as subways and mines,and at the same time supply power to structural health monitoring devices.

关键词： multilink-spring mechanism nonlinear dynamics vibration isolation energy harvester

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

An Elastoplastic Fracture Model Based on Bond-Based Peridynamics

引用

Computer Modeling in engineering & Sciences 2024年第9期140卷 2349-2371页

作者： Liping Zu Yaxun Liu Haoran Zhang Lisheng Liu Xin Lai Hai Mei department of engineering Structure and mechanics Wuhan University of TechnologyWuhan430070China Hubei Key Laboratory of Theory and Application of Advanced Materials mechanics Wuhan University of TechnologyWuhan430070China

Fracture in ductile materials often occurs in conjunction with plastic ***,in the bond-based peridynamic(BB-PD)theory,the classic mechanical stress is not defined *** makes it difficult to describe plasticity directly using the classical plastic *** address the above issue,a unified bond-based peridynamics model was proposed as an effective tool to solve elastoplastic fracture *** to the existing models,the proposed model directly describes the elastoplastic theory at the bond level without the need for additional calculation *** results obtained in the context of this model are shown to be consistent with FEM results in regard to force-displacement curves,displacement fields,stress fields,and plastic deformation *** model exhibits good capability of capturing crack propagation in ductile material failure problems.

关键词： Ductile materials plastic deformation bond-based peridynamics isotropic hardening fracture analysis

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

A Review on the Mullins Effect in Tough Elastomers and Gels

引用

Acta Mechanica Solida Sinica 2024年第2期37卷 181-214页

作者： Lin Zhan Shaoxing Qu Rui Xiao MOE Key Lab of Disaster Forecast and Control in engineering College of Mechanics and Construction EngineeringJinan UniversityGuangzhou510632China State Key Laboratory of Fluid Power and Mechatronic System Key Laboratory of Soft Machines and Smart Devices of Zhejiang ProvinceDepartment of Engineering MechanicsZhejiang UniversityHangzhou310027China

Tough elastomers and gels have garnered broad research interest due to their wide-ranging potential ***,during the loading and unloading cycles,a clear stress softening behavior can be observed in many material systems,which is also named as the Mullins *** this work,we aim to provide a complete review of the Mullins effect in soft yet tough materials,specifically focusing on nanocomposite gels,double-network hydrogels,and multi-network *** first revisit the experimental observations for these soft *** then discuss the recent developments of constitutive models,emphasizing novel developments in the damage mechanisms or network *** phenomenological models will also be briefly *** attention is then placed on the anisotropic and multiaxial modeling *** is demonstrated that most of the existing models fail to accurately predict the multiaxial data,posing a significant challenge for developing future anisotropic models tailored for tough gels and elastomers.

关键词： Mullins effect Double-network hydrogels Nanocomposite gels Multi-network elastomers Anisotropic damage model Multiaxial model

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：