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A joint method to retrieve directional ocean wave spectra from SAR and wave spectrometer data 被引量:2
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作者 任林 杨劲松 +1 位作者 郑罡 王隽 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2016年第4期847-858,共12页
This paper proposes a joint method to simultaneously retrieve wave spectra at dif ferent scales from spaceborne Synthetic Aperture Radar(SAR) and wave spectrometer data. The method combines the output from the two dif... This paper proposes a joint method to simultaneously retrieve wave spectra at dif ferent scales from spaceborne Synthetic Aperture Radar(SAR) and wave spectrometer data. The method combines the output from the two dif ferent sensors to overcome retrieval limitations that occur in some sea states. The wave spectrometer sensitivity coeffi cient is estimated using an ef fective signifi cant wave height(SWH), which is an average of SAR-derived and wave spectrometer-derived SWH. This averaging extends the area of the sea surface sampled by the nadir beam of the wave spectrometer to improve the accuracy of the estimated sensitivity coeffi cient in inhomogeneous sea states. Wave spectra are then retrieved from SAR data using wave spectrometer-derived spectra as fi rst guess spectra to complement the short waves lost in SAR data retrieval. In addition, the problem of 180° ambiguity in retrieved spectra is overcome using SAR imaginary cross spectra. Simulated data were used to validate the joint method. The simulations demonstrated that retrieved wave parameters, including SWH, peak wave length(PWL), and peak wave direction(PWD), agree well with reference parameters. Collocated data from ENVISAT advanced SAR(ASAR), the airborne wave spectrometer STORM, the PHAROS buoy, and the European Centre for Medium-Range Weather Forecasting(ECMWF) were then used to verify the proposed method. Wave parameters retrieved from STORM and two ASAR images were compared to buoy and ECMWF wave data. Most of the retrieved parameters were comparable to reference parameters. The results of this study show that the proposed joint retrieval method could be a valuable complement to traditional methods used to retrieve directional ocean wave spectra, particularly in inhomogeneous sea states. 展开更多
关键词 Synthetic Aperture Radar(SAR) wave spectrometer directional ocean wave spectrum joint method
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A SPARSITY AND COMPRESSION RATIO JOINT ADJUSTMENT METHOD FOR COLLABORATIVE SPECTRUM SENSING 被引量:1
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作者 Chi Jingxiu Zhang Jianwu Xu Xiaorong 《Journal of Electronics(China)》 2012年第6期604-610,共7页
Spectrum sensing is the fundamental task for Cognitive Radio (CR). To overcome the challenge of high sampling rate in traditional spectral estimation methods, Compressed Sensing (CS) theory is developed. A sparsity an... Spectrum sensing is the fundamental task for Cognitive Radio (CR). To overcome the challenge of high sampling rate in traditional spectral estimation methods, Compressed Sensing (CS) theory is developed. A sparsity and compression ratio joint adjustment algorithm for compressed spectrum sensing in CR network is investigated, with the hypothesis that the sparsity level is unknown as priori knowledge at CR terminals. As perfect spectrum reconstruction is not necessarily required during spectrum detection process, the proposed algorithm only performs a rough estimate of sparsity level. Meanwhile, in order to further reduce the sensing measurement, different compression ratios for CR terminals with varying Signal-to-Noise Ratio (SNR) are considered. The proposed algorithm, which optimizes the compression ratio as well as the estimated sparsity level, can greatly reduce the sensing measurement without degrading the detection performance. It also requires less steps of iteration for convergence. Corroborating simulation results are presented to testify the effectiveness of the proposed algorithm for collaborative spectrum sensing. 展开更多
关键词 Collaborative spectrum sensing Sparsity level Compression ratio joint adjustment method
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Analysis profile of the fully grouted rock bolt in jointed rock using analytical and numerical methods 被引量:8
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作者 Ghadimi Mostafa Shahriar Kourosh Jalalifar Hossein 《International Journal of Mining Science and Technology》 SCIE EI 2014年第5期609-615,共7页
The purpose of this study was to investigate the effect of bolt profile on load transfer mechanism of fully grouted bolts in jointed rocks using analytical and numerical methods. Based on the analytical method with de... The purpose of this study was to investigate the effect of bolt profile on load transfer mechanism of fully grouted bolts in jointed rocks using analytical and numerical methods. Based on the analytical method with development of methods, a new model is presented. To validate the analytical model, five different profiles modeled by ANSYS software. The profile of rock bolts T3 and T4with load transfer capacity,respectively 180 and 195 kN in the jointed rocks was selected as the optimum profiles. Finally, the selected profiles were examined in Tabas Coal Mine. FLAC analysis indicates that patterns 6+7 with2 NO flexi bolt 4 m better than other patterns within the faulted zone. 展开更多
关键词 Fully grouted bolt Load transfer mechanism jointed rocks Analytical and numerical methods
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Distinct element modelling of fracture plan control in continuum and jointed rock mass in presplitting method of surface mining 被引量:4
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作者 Sharafisafa Mansour Aliabadian Zeinab +1 位作者 Alizadeh Rezvan Mortazavi Ali 《International Journal of Mining Science and Technology》 SCIE EI 2014年第6期871-881,共11页
Controlled blasting techniques are used to control overbreak and to aid in the stability of the remaining rock formation. Presplitting is one of the most common methods which is used in many open pit mining and surfac... Controlled blasting techniques are used to control overbreak and to aid in the stability of the remaining rock formation. Presplitting is one of the most common methods which is used in many open pit mining and surface blast design. The purpose of presplitting is to form a fracture plane across which the radial cracks from the production blast cannot travel. The purpose of this study is to investigate of effect of presplitting on the generation of a smooth wall in continuum and jointed rock mass. The 2D distinct element code was used to simulate the presplitting in a rock slope. The blast load history as a function of time was applied to the inner wall of each blasthole. Important parameters that were considered in the analysis were stress tensor and fracturing pattern. The blast loading magnitude and blasthole spacing and jointing pattern were found to be very significant in the final results. 展开更多
关键词 Controlled blasting Presplitting method Continuum and jointed rock mass Distinct element modelling
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An empirical method for joint inversion of wave and wind parameters based on SAR and wave spectrometer data
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作者 Yong Wan Xiaona Zhang +2 位作者 Shuyan Lang Ennan Ma Yongshou Dai 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2024年第5期133-144,共12页
Synthetic aperture radar(SAR)and wave spectrometers,crucial in microwave remote sensing,play an essential role in monitoring sea surface wind and wave conditions.However,they face inherent limitations in observing sea... Synthetic aperture radar(SAR)and wave spectrometers,crucial in microwave remote sensing,play an essential role in monitoring sea surface wind and wave conditions.However,they face inherent limitations in observing sea surface phenomena.SAR systems,for instance,are hindered by an azimuth cut-off phenomenon in sea surface wind field observation.Wave spectrometers,while unaffected by the azimuth cutoff phenomenon,struggle with low azimuth resolution,impacting the capture of detailed wave and wind field data.This study utilizes SAR and surface wave investigation and monitoring(SWIM)data to initially extract key feature parameters,which are then prioritized using the extreme gradient boosting(XGBoost)algorithm.The research further addresses feature collinearity through a combined analysis of feature importance and correlation,leading to the development of an inversion model for wave and wind parameters based on XGBoost.A comparative analysis of this model with ERA5 reanalysis and buoy data for of significant wave height,mean wave period,wind direction,and wind speed reveals root mean square errors of 0.212 m,0.525 s,27.446°,and 1.092 m/s,compared to 0.314 m,0.888 s,27.698°,and 1.315 m/s from buoy data,respectively.These results demonstrate the model’s effective retrieval of wave and wind parameters.Finally,the model,incorporating altimeter and scatterometer data,is evaluated against SAR/SWIM single and dual payload inversion methods across different wind speeds.This comparison highlights the model’s superior inversion accuracy over other methods. 展开更多
关键词 synthetic aperture radar(SAR) wave spectrometer extreme gradient boosting(XGBoost) joint inversion method wave and wind parameters
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Experimental and Finite Element Method Studies of J-Lead Solder Joint Reliability 被引量:3
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作者 HongtaoCHen ChunqingWANG +1 位作者 MingyuLI YanhongTIAN 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2005年第3期419-422,共4页
A comprehensive experimental and numerical study of solder joints for plastic leaded chip carrier (PLCC) 84-Pin, 1.27 mm pitch was carried out. The reliability of solder joints was assessed through accelerated thermal... A comprehensive experimental and numerical study of solder joints for plastic leaded chip carrier (PLCC) 84-Pin, 1.27 mm pitch was carried out. The reliability of solder joints was assessed through accelerated thermal cycling at the temperature range of - 55℃-125℃. The samples were taken out to observe the evolution in microstructure, such as grain coarsening, initiation and propagation of cracks. It was found that the Pb-rich phases segregated gradually and formed a continuous layer adjacent to the intermetallic compound (IMC) layer with increasing the number of thermal cycles, resulting in cracks near the solder/lead interface. The response of stress and strain was studied using nonlinear finite element method (FEM), and the results agreed well with the experimental data. 展开更多
关键词 Solder joint RELIABILITY Sn63-Pb37 Finite element method (FEM)
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A Review of Joint Extraction Techniques for Relational Triples Based on NYT and WebNLG Datasets
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作者 Chenglong Mi Huaibin Qin +1 位作者 Quan Qi Pengxiang Zuo 《Computers, Materials & Continua》 2025年第3期3773-3796,共24页
In recent years,with the rapid development of deep learning technology,relational triplet extraction techniques have also achieved groundbreaking progress.Traditional pipeline models have certain limitations due to er... In recent years,with the rapid development of deep learning technology,relational triplet extraction techniques have also achieved groundbreaking progress.Traditional pipeline models have certain limitations due to error propagation.To overcome the limitations of traditional pipeline models,recent research has focused on jointly modeling the two key subtasks-named entity recognition and relation extraction-within a unified framework.To support future research,this paper provides a comprehensive review of recently published studies in the field of relational triplet extraction.The review examines commonly used public datasets for relational triplet extraction techniques and systematically reviews current mainstream joint extraction methods,including joint decoding methods and parameter sharing methods,with joint decoding methods further divided into table filling,tagging,and sequence-to-sequence approaches.In addition,this paper also conducts small-scale replication experiments on models that have performed well in recent years for each method to verify the reproducibility of the code and to compare the performance of different models under uniform conditions.Each method has its own advantages in terms of model design,task handling,and application scenarios,but also faces challenges such as processing complex sentence structures,cross-sentence relation extraction,and adaptability in low-resource environments.Finally,this paper systematically summarizes each method and discusses the future development prospects of joint extraction of relational triples. 展开更多
关键词 Relation triplet extraction joint extraction methods named entity recognition relation extraction
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Interfacial microstructure and mechanical properties of Ti-6Al-4V/Al7050 joints fabricated using the insert molding method 被引量:2
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作者 Hong-xiang Li Xin-yu Nie +4 位作者 Zan-bing He Kang-ning Zhao Qiang Du Ji-shan Zhang Lin-zhong Zhuang 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2017年第12期1412-1423,共12页
Ti-6Al-4V/Al7050 joints were fabricated by a method of insert molding and corresponding interfacial microstructure and mechanical properties were investigated. The interfacial thickness was sensitive to holding temper... Ti-6Al-4V/Al7050 joints were fabricated by a method of insert molding and corresponding interfacial microstructure and mechanical properties were investigated. The interfacial thickness was sensitive to holding temperature during the first stage, and a good metallurgical bonding interface with a thickness of about 90 μm can be obtained at 750°C. X-ray diffraction, transmission electron microscopy, and thermodynamic analyses showed that the interface mainly contained intermetallic compound TiAl_3 and Al matrix. The joints featured good mechanical properties, i.e., shear strength of 154 MPa, tensile strength of 215 MPa, and compressive strength of 283 MPa, which are superior to those of joints fabricated by other methods. Coherent boundaries between Al/TiAl_3 and TiAl_3/Ti were confirmed to contribute to outstanding interfacial mechanical properties and also explained constant fracture occurrence in the Al matrix. Follow-up studies should focus on improving mechanical properties of the Al matrix by deformation and heat treatment. 展开更多
关键词 INTERFACIAL microstructure INTERFACIAL BONDING mechanism mechanical properties INSERT MOLDING method coherent boundaries Ti/Al jointS
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Research on Simulation Methods of Electric Field Intensity on Surface of 10 kV Cable Joint 被引量:1
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作者 Ruxin Zhang Jun Xiong +9 位作者 Zheng Wu Lei Liao Mingyan Wu Gang Du Xueyou Huang Wenpei Jin Haiming Li Jian Zhang Wenli Cheng Binxian Lu 《Energy and Power Engineering》 2020年第4期37-45,共9页
The electric field intensity (EFI) is important characteristic quantity for evaluating the internal insulation state of cable joints. Based on finite element method, this paper proposes two EFI research methods, field... The electric field intensity (EFI) is important characteristic quantity for evaluating the internal insulation state of cable joints. Based on finite element method, this paper proposes two EFI research methods, field-circuit coupling method and equivalent circuit method. The average EFI of the inner surface of the outer semi-conducting shield can be calculated from the current in the measuring circuit. The relative error between these two methods is about 15%, which roughly proves the consistency of the two methods. Further practical application research enables online monitoring of cable joints. 展开更多
关键词 Cable jointS Electric FIELD INTENSITY EQUIVALENT CIRCUIT method Field-Circuit Coupling method Finite Element Simulation Software
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APPLICATION OF THE PROBABILISTIC FRACTURE MECHANICS METHOD OF PREDICTING THE FATIGUE LIFE OF TUBULAR JOINTS 被引量:1
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作者 聂国华 翁智远 刘人怀 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 1994年第11期1017-1023,共7页
In this paper .fatigue strength of T-type tubularjoints subjected to in-planebending or out-of-plane bending load is investigated By, considering material constantsand initial crack sizes as random variables and appl... In this paper .fatigue strength of T-type tubularjoints subjected to in-planebending or out-of-plane bending load is investigated By, considering material constantsand initial crack sizes as random variables and applying Monte Carlo simulation method, we have giyen a statistical analvsis on fatigue life. Simultaneously, linearregression analyses of computed resuldts are performed and compared with that of theknown experimental data. 展开更多
关键词 Monte Carlo simulation method probabilistie fracture mechani-cs FATIGUE tubular joints
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Joint Probabilistic Scheduling and Resource Allocation for Wireless Networked Control Systems
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作者 Meng Zheng Lei Zhang Wei Liang 《IEEE/CAA Journal of Automatica Sinica》 2025年第1期258-260,共3页
Dear Editor,This letter presents a joint probabilistic scheduling and resource allocation method(PSRA) for 5G-based wireless networked control systems(WNCSs). As a control-aware optimization method, PSRA minimizes the... Dear Editor,This letter presents a joint probabilistic scheduling and resource allocation method(PSRA) for 5G-based wireless networked control systems(WNCSs). As a control-aware optimization method, PSRA minimizes the linear quadratic Gaussian(LQG) control cost of WNCSs by optimizing the activation probability of subsystems, the number of uplink repetitions, and the durations of uplink and downlink phases. Simulation results show that PSRA achieves smaller LQG control costs than existing works. 展开更多
关键词 subsystem activation probability linear quadratic gaussian control cost number uplink repetitions wireless networked control systems joint probabilistic scheduling resource allocation method psra linear quadratic gaussian lqg G based activation probability subsystems
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Numerical Simulation of Non-linear Joint Using Displacement Discontinuity Method
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作者 李科 王颖轶 黄醒春 《Journal of Donghua University(English Edition)》 EI CAS 2012年第4期295-298,共4页
An iterative algorithm for modeling of non-linear joint by the displacement discontinuity method (DDM) was described, and the effect of the non-linear joint on the in-situ stress field was investigated in this paper. ... An iterative algorithm for modeling of non-linear joint by the displacement discontinuity method (DDM) was described, and the effect of the non-linear joint on the in-situ stress field was investigated in this paper. The Barton-Bandis (BB) non-linear joint model and failure criterion were adopted in the new DDM program. Using this program, the stress field around the non-linear joint was obtained, the parameters analysis of the joint was carried out, and the deformation and stress distribution of the joint were studied. The simulation results show that: (1)the in-situ stress is significantly affected by the joint; (2)the increase of stiffness, friction angle, and thickness of the joint affect the stress concentration in different ways; (3)the influence distance of the joint changes with the angle of the joint; (4)the deformation and stress of the joint change with the point position. 展开更多
关键词 displacement discontinuity method (DDM) non-linear joint model.. Hnear joint model: stress field: disolacement field
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粗糙裂隙岩体滚刀破岩及裂纹扩展机制
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作者 王培涛 黄浩 +2 位作者 荆国业 周晓敏 解联库 《应用基础与工程科学学报》 北大核心 2026年第1期211-222,共12页
滚刀破岩工作参数和岩体裂隙物理特征是影响硬岩条件下滚刀破岩机理的重要因素.基于MATLAB与AutoCAD平台分别建立光滑离散节理网络(DFN)模型、粗糙离散节理网络(RDFN)模型和三维方形滚刀模型,结合颗粒流离散元PFC数值模拟方法分析了不... 滚刀破岩工作参数和岩体裂隙物理特征是影响硬岩条件下滚刀破岩机理的重要因素.基于MATLAB与AutoCAD平台分别建立光滑离散节理网络(DFN)模型、粗糙离散节理网络(RDFN)模型和三维方形滚刀模型,结合颗粒流离散元PFC数值模拟方法分析了不同侵岩速度和裂隙面粗糙度的破岩效果.研究结果表明:完整岩石滚刀破岩破坏区由岩石表面逐渐向内部延伸,力链呈发散性分布;滚刀侵岩速度对破坏载荷与裂纹数量变化趋势无明显影响,均以剪切裂纹为主.复杂裂隙岩体破裂中力链与裂纹扩展均沿着破坏裂隙面分布,以张拉裂纹为主.破坏区由初始破坏裂隙面处逐渐贯通岩体表面而形成,RDFN模型的破坏载荷较DFN模型的破坏载荷大.RDFN模型与DFN模型的裂纹扩展和破坏模式均受裂隙面控制,裂隙面粗糙度影响着裂纹扩展方向.该研究成果以期为复杂裂隙岩体滚刀破岩机制研究提供有益参考. 展开更多
关键词 裂隙岩体 滚刀破岩 DFN模型 RDFN模型 离散元 节理面表征
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复合材料L型节点仿真方法与试验验证研究
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作者 谌伟 夏润民 +1 位作者 黄继伟 王宇强 《华中科技大学学报(自然科学版)》 北大核心 2026年第1期156-160,共5页
采用单铺层和参数等效两种建模方法对L型节点静强度进行有限元计算,再通过试验对夹芯复合材料L型节点静强度进行对比验证.研究结果表明:单铺层建模方法应变计算结果与试验应变测量结果之间的误差在9%以下,位移计算结果与试验位移测量结... 采用单铺层和参数等效两种建模方法对L型节点静强度进行有限元计算,再通过试验对夹芯复合材料L型节点静强度进行对比验证.研究结果表明:单铺层建模方法应变计算结果与试验应变测量结果之间的误差在9%以下,位移计算结果与试验位移测量结果之间的误差在5%以下,参数等效建模方法应变计算结果与试验应变测量结果之间的误差在17%以下,位移计算结果与试验位移测量结果之间的误差在10%以下,单铺层建模方法的计算结果精度更高,参数等效建模方法可保证位移的计算误差的同时简化建模过程、减少计算量. 展开更多
关键词 夹芯复合材料结构 L型节点 参数等效法 单铺层法 试验验证
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面向中外联合办学模式的工程结构有限元课程建设研究
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作者 曹贻鹏 杜志博 +1 位作者 刘晨 杨洁 《齐齐哈尔高等师范专科学校学报》 2026年第1期121-124,共4页
中外联合办学在工程专业领域取得显著进展。结构有限元分析作为工程领域的核心课程,其教学面临学情、资源、实践等三重挑战。本文从提升本科生专业水平的角度出发,进行了课程建设相关的探索与实践,构建起具有行业特色的课程体系,形成了... 中外联合办学在工程专业领域取得显著进展。结构有限元分析作为工程领域的核心课程,其教学面临学情、资源、实践等三重挑战。本文从提升本科生专业水平的角度出发,进行了课程建设相关的探索与实践,构建起具有行业特色的课程体系,形成了学以致用的教学方式。实践结果表明,所采取的方法对学生掌握专业课知识点及后续对知识的应用均起到了促进作用,为相关课程建设提供参考。 展开更多
关键词 有限元法 工科 中外联合 教学改革
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基于FDEM的地下内衬硐库密封结构-衬砌分缝协同优化设计研究
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作者 孙冠华 王章星 +4 位作者 王娇 董沂鑫 石露 刘治军 林姗 《岩土力学》 北大核心 2026年第2期497-514,共18页
在高内压循环作用下地下储气库衬砌易产生裂缝与渗透通道,密封层受力与裂缝控制问题尤为关键。基于有限-离散元方法(finite-discrete element method,简称FDEM),建立了连续-非连续的围岩-衬砌-密封层整体模型,系统研究了平钢板与波拱两... 在高内压循环作用下地下储气库衬砌易产生裂缝与渗透通道,密封层受力与裂缝控制问题尤为关键。基于有限-离散元方法(finite-discrete element method,简称FDEM),建立了连续-非连续的围岩-衬砌-密封层整体模型,系统研究了平钢板与波拱两类钢衬及预设缝设计参数对衬砌裂缝演化与密封性能的影响。结果表明,平钢板型密封层应力水平和裂缝数量较高,整体性差,预设缝改善衬砌开裂与密封结构受力作用有限;波拱型结构能显著降低峰值应力并改变裂缝分布,使得裂缝多集中在波拱底部,整体裂缝数量减少,但波拱处的裂缝开裂宽度更大。采用波拱+预设缝相结合的方案可进一步均匀化开裂,减少密封钢衬应力。随着波拱和预设缝数量增加,应力分布趋于均匀,裂缝扩展受控,但最大裂缝宽度呈先减后增趋势,钢衬应力模式由拉应力向弯-剪应力转变。当缝设于拱底时,裂缝可沿预设路径均匀扩展,并可结合防排水措施降低渗透风险。总体而言,波拱+预设缝复合设计在引导裂缝、释放应变和提升密封渗透性能方面具有显著优势,为储气库密封-衬砌协同优化设计提供参考。 展开更多
关键词 压缩空气储能 内衬硐库 密封层设计 衬砌分缝设计 有限-离散元方法
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摩擦型腹板自复位梁柱节点初始转动刚度研究
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作者 周凌宇 许磊 +4 位作者 陈浩 阳凡 王其良 方蛟鹏 贺学军 《湖南大学学报(自然科学版)》 北大核心 2026年第3期35-43,共9页
为精准考量自复位节点的初始转动刚度和明确连接件间摩擦对初始转动刚度的贡献,设计了一种摩擦型腹板自复位梁柱延性节点.该节点由摩擦腹板、预应力索、上下狗骨形翼缘连接板、黄铜摩擦片、高强度摩擦型螺栓构成.设计了两种不同尺寸的... 为精准考量自复位节点的初始转动刚度和明确连接件间摩擦对初始转动刚度的贡献,设计了一种摩擦型腹板自复位梁柱延性节点.该节点由摩擦腹板、预应力索、上下狗骨形翼缘连接板、黄铜摩擦片、高强度摩擦型螺栓构成.设计了两种不同尺寸的狗骨形翼缘连接板和不同预应力的预应力索,并通过试验得到节点弯矩-转角及各组件的相关材性数据.随后,基于欧洲规范EC3中组件法相关原理,推导得到该节点初始转动刚度计算公式.引入Iwan模型表征摩擦的力学行为,将摩擦腹板中的摩擦等效为组件法中的弹簧模型.试验结果与计算公式对比分析表明,二者吻合良好且摩擦腹板对转动刚度的贡献不可忽略. 展开更多
关键词 自复位节点 初始转动刚度 摩擦腹板 组件法 Iwan模型
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基于耦合渗流分析的CEL方法研究盾构隧道涌水涌砂灾害机理及控制措施
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作者 郑刚 邱惠敏 +2 位作者 张天奇 陈至通 刘梦韶 《岩土工程学报》 北大核心 2026年第4期673-686,共14页
富水粉土、粉(细)砂地层中盾构隧道涌水涌砂灾害事故频发。提出了一种可耦合渗流分析(seepage analysis)的欧拉-拉格朗日数值方法(Coupled Eulerian-Lagrangian Method,简称CEL方法),即S-CEL方法,用于模拟盾构隧道管片接缝渗漏发生后土... 富水粉土、粉(细)砂地层中盾构隧道涌水涌砂灾害事故频发。提出了一种可耦合渗流分析(seepage analysis)的欧拉-拉格朗日数值方法(Coupled Eulerian-Lagrangian Method,简称CEL方法),即S-CEL方法,用于模拟盾构隧道管片接缝渗漏发生后土体流失、结构变形与管片接缝渗漏点演生的耦合灾变过程。首先通过两个渗漏试验对所提出的方法进行了验证。进而基于某地铁盾构隧道涌水涌砂事故,利用S-CEL方法再现了灾害发展过程,并与实测结果进行了对比验证,揭示了管片接缝渗漏点演生顺序,以及土体流失机理和隧道结构响应机制。研究表明,管片接缝渗漏点沿着隧道纵向渐进演生,伴随着土体流失质量急剧增加,黏、砂土层交界面位置处产生侵蚀空腔,隧道出现严重不均匀沉降和错台变形,管片混凝土发生损伤。最后,研究了灾害抢险措施,建议灾害发生后,应尽快采取应急降水措施和隧道临时加固措施,可有效延缓后续漏点的产生。 展开更多
关键词 盾构隧道 涌水涌砂 S-CEL方法 漏点演生 土体流失 管片损伤
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炮位侦校雷达联合定位算法研究
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作者 闫海 张炜轩 +2 位作者 韩文俊 王晓东 周垂红 《现代雷达》 北大核心 2026年第1期34-40,共7页
强杂波、目标雷达散射截面积起伏会增大量测噪声,严重影响测角精度。传统炮位侦校雷达弹道外推算法对单个弹丸目标的跟踪量测数据做滤波后进行外推定位,当量测误差大时滤波估计误差大且收敛慢,难以满足高精度定位要求。针对低信噪比环... 强杂波、目标雷达散射截面积起伏会增大量测噪声,严重影响测角精度。传统炮位侦校雷达弹道外推算法对单个弹丸目标的跟踪量测数据做滤波后进行外推定位,当量测误差大时滤波估计误差大且收敛慢,难以满足高精度定位要求。针对低信噪比环境下高精度外推定位问题,文中提出一种基于多轨迹联合量测滤波(MTLF)的炮群定位算法,使用多发弹丸融合量测结果代替单发量测结果代入滤波方程,减少滤波后验估计误差,提高定位一致性。为验证算法有效性,使用仿真模拟器生成弹丸在不同射击条件下多组量测数据,比较了与传统方法在量测误差、滤波精度与定位精度上的表现。仿真结果表明:相对于传统方法,该方法可有效抑制量测误差,提高滤波精度,减少炮群定位圆中间误差,并具备较好的鲁棒性,有很强的实用价值。 展开更多
关键词 炮位侦校雷达 低信噪比 量测误差 滤波 联合定位
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考虑结构刚度变化的盾构隧道纵向变形计算方法
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作者 甘晓露 李文博 +2 位作者 龚晓南 刘念武 俞建霖 《工程力学》 北大核心 2026年第4期212-223,共12页
为适应复杂的外部环境,盾构隧道纵向结构刚度有可能会存在突变。以前人研究为基础,提出考虑结构刚度纵向变化的Timoshenko短梁-弹簧盾构隧道模型,并通过Pasternak地基模型和边界弹簧考虑地基土变形连续性和任意隧道边界条件。基于有限... 为适应复杂的外部环境,盾构隧道纵向结构刚度有可能会存在突变。以前人研究为基础,提出考虑结构刚度纵向变化的Timoshenko短梁-弹簧盾构隧道模型,并通过Pasternak地基模型和边界弹簧考虑地基土变形连续性和任意隧道边界条件。基于有限差分理论推导了外部荷载影响下盾构隧道纵向变形的耦合解答,利用模型退化、数值模型和实际工程案例验证了计算方法的正确性和有效性,并结合参数分析研究了高刚度管片的存在对盾构隧道纵向变形响应的影响。结果表明:局部使用高刚度管片可有效抑制高刚度管片段内的隧道沉降和环缝接头变形,但刚度差异会导致高刚度段两端出现接头变形突增;高刚度管片与常规管片刚度差异越大,高刚度段内的隧道变形越小,但高刚度段两侧接头变形突增的现象更加显著;不同高刚度段长度和结构刚度比组合情况下的隧道变形控制效果存在显著差异,不合理的参数组合甚至会加剧隧道变形。 展开更多
关键词 盾构隧道 结构刚度变化 纵向变形 环缝接头 有限差分法
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