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A practical parallel preprocessing strategy for 3D numerical manifold method

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Science China(Technological Sciences) 2022年第12期65卷 2856-2865页

作者： yang yongtao LI JunFeng 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

Over the past three decades,the numerical manifold method(NMM)has attracted many researchers from geotechnical community because it unifies the solutions of continuous and discontinuous problems in the same ***,due to the lack of ready-made preprocessing tools,the development of three dimensional NMM(3DNMM)is still limited.A practical strategy to generate the discretized models for a 3DNMM analysis is *** the proposed strategy,regular hexahedral meshes are uniformly deployed to construct the mathematical cover *** physical meshes including the joints,material interfaces,and problem domain boundaries are adopted to cut the mathematical cover system into physical cover system and manifold elements(MEs).To improve the efficiency of the proposed strategy,the Intel threading building blocks(TBB)parallel library for CPU paralleling is *** typical examples are adopted to validate the proposed *** results show that the proposed strategy can effectively generate the discretized 3D models of some geotechnical problems for 3DNMM *** proposed strategy deserves a further investigation.

关键词： three-dimensional numerical manifold method 3D cutting parallel programming physical system encoding

Modelling three dimensional dynamic problems using the fournode tetrahedral element with continuous nodal stress

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Science China(Technological Sciences) 2018年第12期61卷 1889-1900页

作者： ZHANG GuoHua yang yongtao State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of Sciences

A partition of unity(PU) based four-node tetrahedral element with continuous nodal stress(Tetr4-CNS) was recently proposed for static analysis of three-dimensional solids. By simply using the same mesh as the classical four-node tetrahedral(Tetr4)element, high order global approximation function in the Tetr4-CNS element can be easily constructed without extra nodes or nodal DOFs. In this paper, the Tetr4-CNS element is further applied in the analysis of three dimensional dynamic problems. A series of free vibration and forced vibration problems are solved using the Tetr4-CNS element. The numerical results show that,for regular meshes, accuracy obtained using the Tetr4-CNS element is superior to that obtained using the Tetr4 and eight-node hexahedral(Hexa8) elements. For distorted meshes, the Tetr4-CNS element has better mesh-distortion tolerance than both the Tetr4 and Hexa8 elements.

关键词： partition of unity tetrahedral element Tetr4-CNS mesh distortion dynamic problems

高强度间歇运动和中等强度持续运动对抑制功能影响的元分析

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首都体育学院学报 2024年第1期36卷 105-116页

作者：刘运洲李亚靖杨勇涛国家体育总局体育科学研究所北京100061 鲁东大学山东烟台264025 天津体育学院竞技运动心理与生理调控重点实验室天津300381

目的:使用元分析方法探讨高强度间歇运动(HIIT)对抑制功能的影响及其影响因素,以及与中等强度持续运动(MICT)相比的效果差异,为不同锻炼人群选择合适的锻炼方式提供依据。方法:依据PRISMA原则,在国内外的一些检索平台检索相关文献,检索... 详细信息

目的:使用元分析方法探讨高强度间歇运动(HIIT)对抑制功能的影响及其影响因素,以及与中等强度持续运动(MICT)相比的效果差异,为不同锻炼人群选择合适的锻炼方式提供依据。方法:依据PRISMA原则,在国内外的一些检索平台检索相关文献,检索时间为2010年1月1日—2022年8月30日。运用软件“Stata 15.0”和软件“Review Manager 5.3”进行效应量分析。结果:1)HIIT能够显著提高运动者的抑制功能,为中等效应量。2)HIIT能够显著提高10~24岁人群的抑制功能,而对25岁以上人群的抑制功能未见显著影响;90%~100%最大心率运动强度的HIIT能够显著提高运动者的抑制功能,且合并效应量较大,70%~90%最大心率运动强度的HIIT能够显著提高运动者的抑制功能;10~30 min和30~60 min的HIIT均能显著提高运动者的抑制功能;功率自行车、篮球、爬楼梯等方式的HIIT能显著提高运动者的抑制功能,跑步机上跑步的HIIT对运动者的抑制功能未见显著影响;HIIT结束30 min后仍对运动者的抑制功能有积极影响。3)HIIT与MICT对抑制功能的影响未见显著性差异。结论:HIIT能够提高运动者的抑制功能,为中等效应量,HIIT与MICT对抑制功能的积极影响没有差异;HIIT与抑制功能的关系受到年龄、运动强度、运动时间、运动方式等调节变量的影响,HIIT的认知促进效益可以持续30 min以上。

关键词：高强度间歇运动中等强度持续运动抑制功能元分析

Numerical study of soil-rock mixture:Generation of random aggregate structure

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Science China(Technological Sciences) 2018年第3期61卷 359-369页

作者： CHEN Li yang yongtao ZHENG Hong State Key Laboratory of Geotechnical Engineering Institute of Rock and Soil Mechanics Chinese Academy of Sciences Key Laboratory of Urban Security and Disaster Engineering Ministry of Education Beijing University of Technology

The soil-rock mixture(SRM) is highly heterogeneous. Before carrying out numerical analysis,a structure model should be generated. A reliable way to obtain such structure is by generating random aggregate structure based on random sequential addition(RSA). The classical RSA is neither efficient nor robust since valid positions to place new inclusions are formulated by trial, which involves repetitive overlapping tests. In this paper, the algorithm of Entrance block between block A and B(EAB)is synergized with background mesh to redesign RSA so that permissible positions to place new inclusions can be predicted,resulting in dramatic improvement in efficiency and robustness.

关键词： soil-rock mixture(SRM) random aggregate structure(RAS) random sequential addition(RSA) EAB algorithm background mesh

A partition-of-unity based three-node triangular element with continuous nodal stress using radial-polynomial basis functions

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Science China(Technological Sciences) 2017年第10期60卷 1518-1536页

作者： yang yongtao ZHENG Hong XU DongDong State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of Sciences Key Laboratory of Urban Security and Disaster Engineering Ministry of EducationBeijing University of Technology Key Laboratory of Geotechnical Mechanics and Engineering of Ministry of Water Resources Yangtze River Scientific Research Institute

A partition-of-unity （PU） based ＂FE-Meshfree＂ three-node triangular element （Trig3-RPIM） was recently developed for linear elastic problems. This Trig3-RPIM element employs hybrid shape functions that combine the shape functions of three-node triangular element （Trig3） and radial-polynomial basis functions for the purpose of synergizing the merits of both finite element method and meshfree method. Although Trig3-RPIM element is capable of obtaining higher accuracy and convergence rate than the Trig3 element and four-node iso-parametric quadrilateral element without adding extra nodes or degrees of freedom （DOFs）, the nodal stress field through Trig3-RP1M element is not continuous and extra stress smooth operations are still needed in the post processing stage. To further improve the property of Trig3-RPIM element, a new PU-based triangular element with continuous nodal stress, called Trig3-RPIMcns, is developed. Numerical examples including several linear, free vibration and forced vibration test problems, have confirmed the correctness and feasibility of the proposed Trig3-RPIMcns element.

关键词： partition of unity FE-Meshfree element Trig3-RPlMcns mesh distortion radial-polynomial basis functions

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铁路机务数据集成共享平台设计与应用

控制与信息技术 2024年第2期 111-116页

作者：赵超杨永滔蓝凡株洲中车时代电气股份有限公司湖南株洲412001

为解决铁路机务数据集成难、治理复杂以及共享效率低的问题,文章提出了一套机务数据集成共享平台建设方案。其首先通过多源异构数据采集技术,实现将不同系统数据自动定时采集进入数据仓库中;然后针对数据仓库中数据进行分级、分类标准... 详细信息

为解决铁路机务数据集成难、治理复杂以及共享效率低的问题,文章提出了一套机务数据集成共享平台建设方案。其首先通过多源异构数据采集技术,实现将不同系统数据自动定时采集进入数据仓库中;然后针对数据仓库中数据进行分级、分类标准化治理,形成业务主题及专题库,同时提供了基于安全管控下的实时及离线数据共享模式,实现了数据面向不同场景下的数据共享。通过该平台在现场的建设,实现了节省机车预排检修计划时间70%以上、降低机车整备平均停时约20 min的效果。这表明该机务数据集成共享平台有助于促进多系统数据共享融合、提升铁路机务信息化水平、生产效率和管理能力。

关键词：铁路机务数据数据集成数据共享数据治理信息化大数据

维普期刊数据库博看期刊

Searching for critical slip surfaces of slopes using stress fields by numerical manifold method

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Journal of Rock Mechanics and Geotechnical Engineering 2020年第6期12卷 1313-1325页

作者： yongtao yang Wenan Wu Hong Zheng State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China University of Chinese Academy of Sciences Beijing100049China Key Laboratory of Urban Security and Disaster Engineering Ministry of EducationBeijing University of TechnologyBeijing100124China

This study first reviews the numerical manifold method(NMM)which possesses some advantages over the traditional limit equilibrium methods(LEMs)in calculating the factors of safety(Fs)of the ***,with regard to a trial slip surface(TSS),associated stress fields reproduced by NMM as well as the enhanced limit equilibrium method are combined to compute *** order to search for the potential critical slip surface(CSS),the MAX-MIN ant colony optimization algorithm(MMACOA),one of the best performing algorithms for some optimization problems,is *** to obtain Fs in conjunction with the potential CSS are ***,the proposed numerical model and traditional methods are compared with stability analysis of three typical *** numerical results show that Fs and CSSs of the slopes can be accurately calculated with the proposed model.

关键词： Enhanced limit method Ant colony algorithm Numerical manifold method(NMM) Slope stability

A high order numerical manifold method and its application to linear elastic continuous and fracture problems

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Science China(Technological Sciences) 2018年第3期61卷 346-358页

作者： yang yongtao SUN GuanHua CAI KeJian ZHENG Hong State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil Mechanics Chinese Academy of Sciences School of Civil and Transportation Engineering NingBo University of Technology Key Laboratory of Urban Security and Disaster Engineering Ministry ofEducation Beijing University of Technology

The numerical manifold method(NMM) is a partition of unity(PU) based method. For the purpose of obtaining better accuracy with the same mesh, high order global approximation can be adopted by increasing the order of local approximations(LAs). This,however, will cause the "linear dependence"(LD) issue, where the global matrix is rank deficient even after sufficient constraints are enforced. In this paper, through quadrilateral mesh to form the mathematical cover, a high order numerical manifold method called Quad4-COLS(NMM) is developed, where the constrained and orthonormalized least-squares method(CO-LS) is used to construct the LAs. The developed Quad4-COLS(NMM) does not need extra nodes or DOFs to construct high order global approximations, while is free from the LD issue. Nine numerical tests including five tests for linear elastic continuous problems and four tests for linear elastic fracture problems are carried out to validate the accuracy and robustness of the proposed Quad4-COLS(NMM).

关键词： partition of unity based methods numerical manifold method Quad4-COLS(NMM) crack propagation linear dependence

Modeling complex crack problems using the three-node triangular element fitted to numerical manifold method with continuous nodal stress

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Science China(Technological Sciences) 2017年第10期60卷 1537-1547页

作者： yang yongtao XU DongDong SUN GuanHua ZHENG Hong State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of Sciences Key Laboratory of Geotechnical Mechanics and Engineering of Ministry of Water Resources Yangtze River Scientific Research Institute Key Laboratory of Urban Security and Disaster Engineering Ministry of EducationBeijing University of Technology

A three-node triangular element fitted to numerical manifold method with continuous nodal stress, called Trig_3-CNS(NMM)element, was recently proposed for linear elastic continuous problems and linear elastic simple crack problems. The Trig_3-CNS(NMM) element can be considered as a development of both the Trig_3-CNS element and the numerical manifold method(NMM).Inheriting all the advantages of Trig_3-CNS element, calculations using Trig_3-CNS(NMM) element can obtain higher accuracy than Trig_3 element without extra degrees of freedom(DOFs) and yield continuous nodal stress without stress smoothing. Inheriting all the advantages of NMM, Trig_3-CNS(NMM) element can conveniently treat crack problems without deploying conforming mathematical mesh. In this paper,complex problems such as a crucifix crack and a star-shaped crack with many branches are studied to exhibit the advantageous features of the Trig_3-CNS(NMM) element. Numerical results show that the Trig_3-CNS(NMM) element is prominent in modeling complex crack problems.

关键词： numerical manifold method Trig3-CNS (NMM) element stress intensity factor complex crack problems