期刊文献+
任意字段
题名或关键词
题名
关键词
摘要
作者
第一作者
机构
刊名
分类号
参考文献
作者简介
基金资助
栏目信息
共找到9篇文章
< 1 >
每页显示 20 50 100
已选0条
引用分析
参考文献
引证文献
 统计分析
检索结果
已选文献
显示方式：
Three-Dimensional Discrete Observability Analysis for Air-to-Air Missile Target Tracking 认领 引用
1
作者 Fei Liu Zhang Ren Yuan Liang 《Journal of Beijing Institute of Technology》 EI CAS 2017年第4期548-556,共9页
The interception information of infrared（ IR）-guided air-to-air missiles（ AAM） is mainly estimated only using the basic bearing measurements. In order to intercept highly maneuverable targets,it is essential to st... The interception information of infrared（ IR）-guided air-to-air missiles（ AAM） is mainly estimated only using the basic bearing measurements. In order to intercept highly maneuverable targets,it is essential to study the system observability to improve the target tracking system performance.The uniqueness of this paper is that the observability analysis is derived based on a discrete three-dimensional （3D） system model. During the maneuvering scenario,the system is approximated by a segment-by-segment system. The relationship between missile-target motion and observability is given by direct and dual approaches. Meanwhile sufficient observability conditions are derived. Moreover,a numerical simulation is conducted and an alternate method is provided to reinforce the proposed observability analysis results. 展开更多
关键词 air-to-air missile （AAM） 3D discrete system target tracking observability analysis
暂未订购 下载PDF
3D DEM simulation of hard rock fracture in deep tunnel excavation induced by changes in principal stress magnitude and orientation 认领 引用 被引量：7
2
作者 Weiqi Wang Xia-Ting Feng +2 位作者 Qihu Wang Rui Kong Chengxiang Yang 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第10期3870-3884,共15页
To achieve the loading of the stress path of hard rock,the spherical discrete element model(DEM)and the new flexible membrane technology were utilized to realize the transient loading of three principal stresses with ... To achieve the loading of the stress path of hard rock,the spherical discrete element model(DEM)and the new flexible membrane technology were utilized to realize the transient loading of three principal stresses with arbitrary magnitudes and orientations.Furthermore,based on the deep tunnel of China Jinping Underground Laboratory II(CJPL-II),the deformation and fracture evolution characteristics of deep hard rock induced by excavation stress path were analyzed,and the mechanisms of transient loading-unloading and stress rotation-induced fractures were revealed from a mesoscopic perspective.The results indicated that the stressestrain curve exhibits different trends and degrees of sudden changes when subjected to transient changes in principal stress,accompanied by sudden changes in strain rate.Stress rotation induces spatially directional deformation,resulting in fractures of different degrees and orientations,and increasing the degree of deformation anisotropy.The correlation between the degree of induced fracture and the unloading magnitude of minimum principal stress,as well as its initial level is significant and positive.The process of mechanical response during transient unloading exhibits clear nonlinearity and directivity.After transient unloading,both the minimum principal stress and minimum principal strain rate decrease sharply and then tend to stabilize.This occurs from the edge to the interior and from the direction of the minimum principal stress to the direction of the maximum principal stress on theε1-ε3 plane.Transient unloading will induce a tensile stress wave.The ability to induce fractures due to changes in principal stress magnitude,orientation and rotation paths gradually increases.The analysis indicates a positive correlation between the abrupt change amplitude of strain rate and the maximum unloading magnitude,which is determined by the magnitude and rotation of principal stress.A high tensile strain rate is more likely to induce fractures under low minimum principal stress. 展开更多
关键词 Deep hard rock tunnel Three-dimensional(3D)discrete element model(DEM) Magnitude and orientation of principal stress Transient unloading Fracture mechanism
暂未订购 下载PDF
3D random Voronoi grain-based models for simulation of brittle rock damage and fabric-guided micro-fracturing 认领 引用 被引量：51
3
作者 E.Ghazvinian M.S.Diederichs R.Quey 《Journal of Rock Mechanics and Geotechnical Engineering》 CSCD 2014年第6期506-521,共16页
A grain-based distinct element model featuring three-dimensional （3D） Voronoi tessellations （randompoly-crystals） is proposed for simulation of crack damage development in brittle rocks. The grainboundaries in pol... A grain-based distinct element model featuring three-dimensional （3D） Voronoi tessellations （randompoly-crystals） is proposed for simulation of crack damage development in brittle rocks. The grainboundaries in poly-crystal structure produced by Voronoi tessellations can represent flaws in intact rockand allow for numerical replication of crack damage progression through initiation and propagation ofmicro-fractures along grain boundaries. The Voronoi modelling scheme has been used widely in the pastfor brittle fracture simulation of rock materials. However the difficulty of generating 3D Voronoi modelshas limited its application to two-dimensional （2D） codes. The proposed approach is implemented inNeper, an open-source engine for generation of 3D Voronoi grains, to generate block geometry files thatcan be read directly into 3DEC. A series of Unconfined Compressive Strength （UCS） tests are simulated in3DEC to verify the proposed methodology for 3D simulation of brittle fractures and to investigate therelationship between each micro-parameter and the model＇s macro-response. The possibility of numericalreplication of the classical U-shape strength curve for anisotropic rocks is also investigated innumerical UCS tests by using complex-shaped （elongated） grains that are cemented to one another alongtheir adjoining sides. A micro-parameter calibration procedure is established for 3D Voronoi models foraccurate replication of the mechanical behaviour of isotropic and anisotropic （containing a fabric） rocks. 2014 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting byElsevier B.V. All rights reserved. 展开更多
关键词 Numerical modelling 3D Voronoi tessellation Discrete element method Grain-based model Crack damage thresholds Fabric-guided micro-fracturing Anisotropy
暂未订购 下载PDF
A method for evaluating the stability of roadway surrounding rock based on a modified damage evolution characteristic model considering rock mass residual strength and 3D DEM 认领 引用
4
作者 Shengrong Xie Yuxuan Wang +2 位作者 Yiyi Wu Jian Yang Zhigen Wang 《Rock Mechanics Bulletin》 CAS CSCD 2026年第2期101-120,共20页
Repetitive mining in multi-seam conditions induces cumulative damage to surrounding rock,significantly increasing the risk of roadway instability.Taking the roadway in the extra-thick coal seam fully mechanized topcoa... Repetitive mining in multi-seam conditions induces cumulative damage to surrounding rock,significantly increasing the risk of roadway instability.Taking the roadway in the extra-thick coal seam fully mechanized topcoal caving face as the research object,this study innovatively developed a modified damage evolution characteristic model that considers the residual strength of rock mass to quantify the regulatory effect of damage variable D on roof fracture span:damage to the main roof reduces the initial and periodic fracture spans,significantly increasing the probability of sliding and rotational instability of the voussoir beam structure.On this basis,a three-dimensional discrete element method(3D DEM)model was established,and orthogonal tests were designed to reveal the coupling mechanism of the spatial position of fracture lines and coal pillar width on rock mass damage.The results show that when the coal pillar width increases from 8 m to 16 m,the peak stress at the roadway ribs decreases by 26.5%-43.3%,and the influence range of the second invariant of the deviatoric stress tensor(J2)shrinks.The attenuation of stress gradient leads to a decrease in the evolution rate of plastic damage with increasing coal pillar width,while the position of the fracture line has a weak regulatory effect on the stressplastic response of the coal pillar.The results of theoretical analysis and 3D DEM simulations have effectively guided on-site engineering practice. 展开更多
关键词 Multi-seam mining Modified damage evolution characteristic model Three-dimensional discrete element method(3D DEM) Coal pillar width Fracture line position
Fluorometric Discrimination Technique of Phytoplankton Population Based on Wavelet Analysis 认领 引用
5
作者 ZHANG Shanshan SU Rongguo +3 位作者 DUAN Yali ZHANG Cui SONG Zhijie WANG Xiulin 《Journal of Ocean University of China》 SCIE CAS 2012年第3期339-346,共8页
The discrete excitation-emission-matrix fluorescence spectra (EEMS) at 12 excitation wavelengths (400, 430, 450, 460, 470, 490, 500, 510, 525, 550, 570, and 590 nm) and emission wavelengths ranging from 600-750 nm wer... The discrete excitation-emission-matrix fluorescence spectra (EEMS) at 12 excitation wavelengths (400, 430, 450, 460, 470, 490, 500, 510, 525, 550, 570, and 590 nm) and emission wavelengths ranging from 600-750 nm were determined for 43 phytoplankton species. A two-rank fluorescence spectra database was established by wavelet analysis and a fluorometric discrimination technique for determining phytoplankton population was developed. For laboratory simulatively mixed samples, the samples mixed from 43 algal species (the algae of one division accounted for 25%, 50%, 75%, 85%, and 100% of the gross biomass, respectively), the average discrimination rates at the level of division were 65.0%, 87.5%, 98.6%, 99.0%, and 99.1%, with average relative contents of 18.9%, 44.5%, 68.9%, 73.4%, and 82.9%, respectively; the samples mixed from 32 red tide algal species (the dominant species accounted for 60%, 70%, 80%, 90%, and 100% of the gross biomass, respectively), the average correct discrimination rates of the dominant species at the level of genus were 63.3%, 74.2%, 78.8%, 83.4%, and 79.4%, respectively. For the 81 laboratory mixed samples with the dominant species accounting for 75% of the gross biomass (chlorophyll), the discrimination rates of the dominant species were 95.1% and 72.8% at the level of division and genus, respectively. For the 12 samples collected from the mesocosm experiment in Maidao Bay of Qingdao in August 2007, the dominant species of the 11 samples were recognized at the division level and the dominant species of four of the five samples in which the dominant species accounted for more than 80% of the gross biomass were discriminated at the genus level; for the 12 samples obtained from Jiaozhou Bay in August 2007, the dominant species of all the 12 samples were recognized at the division level. The technique can be directly applied to fluorescence spectrophotometers and to the developing of an in situ algae fluorescence auto-analyzer for phytoplankton population. 展开更多
关键词 phytoplankton population 3D discrete fluorescence spectra wavelet analysis two-rank database discrimination
暂未订购 下载PDF
Inconsistent effect of dynamic load waveform on macro-and micro-scale responses of ballast bed characterized in individual cycle:a numerical study 认领 引用 被引量：4
6
作者 Longlong Fu Yuexiao Zheng +1 位作者 Yongjia Qiu Shunhua Zhou 《Railway Engineering Science》 2023年第4期370-380,共11页
Cyclic load is widely adopted in laboratory to simulate the effect of train load on ballast bed.The effectiveness of such load equivalence is usually testified by having similar results of key concerns of ballast bed,... Cyclic load is widely adopted in laboratory to simulate the effect of train load on ballast bed.The effectiveness of such load equivalence is usually testified by having similar results of key concerns of ballast bed,such as deformation or stiffness,while the consistency of particle scale characteristics under two loading patterns is rarely examined,which is insufficient to well-understand and use the load simplification.In this study,a previous laboratory model test of ballast bed under cyclic load is rebuilt using 3D discrete element method(DEM),which is validated by dynamic responses monitored by high-resolution sensors.Then,train load having the same magnitude and amplitude as the cyclic load is applied in the numerical model to obtain the statistical characteristics of inter-particle contact force and particle movements in ballast bed.The results show that particle scale responses under two loading patterns could have quite deviation,even when macro-scale responses of ballast bed under two loading patterns are very close.This inconsistency indicates that the application scale of the DEM model should not exceed the validation scale.Moreover,it is important to examine multiscale responses to validate the effectiveness of load simplification. 展开更多
关键词 Railway ballast Particle movements Contact distribution Waveform sensitivity 3D discrete element method
暂未订购 下载PDF
Compression Algorithm for Implicit 3D B-Spline Solids 认领 引用 被引量：1
7
作者 Yanzhi Song Yixin Luo +2 位作者 Yuan Liu Jiansong Deng Zhouwang Yang 《Communications in Mathematics and Statistics》 SCIE 2018年第2期119-140,共22页
Due to advantages in solid modeling with complex geometry and its ideal suitability for 3D printing,the implicit representation has been widely used in recent years.The demand for free-form shapes makes the implicit t... Due to advantages in solid modeling with complex geometry and its ideal suitability for 3D printing,the implicit representation has been widely used in recent years.The demand for free-form shapes makes the implicit tensor-product B-spline representation attract more and more attention.However,it is an important challenge to deal with the storage and transmission requirements of enormous coefficient ten-sor.In this paper,we propose a new compression framework for coefficient tensors of implicit 3D tensor-product B-spline solids.The proposed compression algorithm consists of four steps,i.e.,preprocessing,block splitting,using a lifting-based 3D discrete wavelet transform,and coding with 3D set partitioning in hierarchical trees algorithm.Finally,we manage to lessen the criticism of the implicit tensor-product B-spline representation of surface for its redundancy store of 3D coefficient tensor.Experimental results show that the proposed compression framework not only achieves satisfactory reconstruction quality and considerable compression ratios,but also sup-ports progressive transmissions and random access by employing patch-wise coding strategy. 展开更多
关键词 Implicit tensor-product B-spline Compression 3D discrete wavelet transform 3D SPIHT Progressive transmission Additive manufacturing
Pseudo-dynamic analysis of a 3D tunnel face in inclined weak strata 认领 引用 被引量：4
8
作者 Sheng Xu Jing Liu Xiao-Li Yang 《Underground Space》 SCIE EI CSCD 2023年第5期156-166,共11页
A new discretization technique is proposed for a three-dimensional(3D)tunnel face in weak strata with a random position in space.This method limits the angle,height,and thickness of the strata on the tunnel face.The o... A new discretization technique is proposed for a three-dimensional(3D)tunnel face in weak strata with a random position in space.This method limits the angle,height,and thickness of the strata on the tunnel face.The original whole piece of soil is separated by a series of parallel planes,and two parallel planes are used as a stratum.Each radial discrete plane is separated when it passes through the strata,and the change in the soil properties of discrete points on the truncated plane is considered separately inside the strata.Considering the spatial and temporal characteristics of seismic waves,a pseudo-dynamic analysis of the tunnel face is carried out.The tunnel face active damage types under earthquake conditions are quantitatively analyzed,and the corresponding support pressure design diagrams are given for the case without weak strata.For the case containing weak strata,the presence of weak strata can have adverse effects on the face.The failure mechanism of the weak strata is given by the discretization method.For different friction angles,the presence of the weak strata changes the friction angles of the soils.For the thickness,location and angle of the weak strata,the variation in the support pressure is given in this paper.To more intuitively depict the change in the failure mechanism in the presence of weak strata,the change in the failure mechanism under different thicknesses and weaknesses of weak strata is plotted. 展开更多
关键词 Tunnel face 3D discretization technique Weak strata Pseudo-dynamic
Image-based numerical study of three-dimensional meso-structure effects on damage and failure of heterogeneous coal-rock under dynamic impact loads 认领 引用 被引量：1
9
作者 Kehong Zheng Bingjing Qiu +3 位作者 Zhenyu Wang Xuefeng Li Jianping Li Kuidong Gao 《Particuology》 SCIE EI CAS CSCD 2020年第4期132-141,共10页
This paper proposes a numerical three-dimensional(3D)mesoscopic approach based on the discrete element method combined with X-ray computed tomography(XCT)images to characterize the dynamic impact behavior of heterogen... This paper proposes a numerical three-dimensional(3D)mesoscopic approach based on the discrete element method combined with X-ray computed tomography(XCT)images to characterize the dynamic impact behavior of heterogeneous coal-rock(HCR).The dynamic impact loading in three directions was modelled to investigate the effects of the 3D meso-structure on the failure patterns and fracture mechanism,with different impact velocities.The XCT image-based discrete element model of HCR was calibrated through appropriate standard uniaxial compression tests.Numerical simulations were carried out to investigate how the breakage behaviors are affected by different loading directions with different impact velocities.The loading direction,input energy,and spatial distribution of the mineral phase had a remarkable influence on the failure patterns and load-carrying capacities.The shape of the gangue phase and the approximate location of the gangue interfaces are key parameters to consider when investigating the failure patterns and fracture mechanism of heterogeneous rock materials.The damage and fracture tended to propagate from the surfaces to the HCR interior.The gangue phase area contacting the loading wall,growth direction of the strong gangue interfaces,and loading directions greatly influenced the failure patterns of the heterogeneous rock materials. 展开更多
关键词 Heterogeneous coal-rock Impact loads X-ray computed tomography(XCT) 3D image-based discrete element modelling Failure pattern
已选0条
引用分析
参考文献
引证文献
 统计分析
检索结果
已选文献
上一页 1 下一页 到第 页
在线咨询 使用帮助 返回顶部 意见反馈