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Deformation coordination analysis of CC-RCC combined dam structures under dynamic loads 被引量:1
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作者 Bo-wen Shi Ming-chao Li +2 位作者 Ling-guang Song Meng-xi Zhang Yang Shen 《Water Science and Engineering》 EI CAS CSCD 2020年第2期162-170,共9页
A combined dam structure using different concrete materials offers many practical benefits.There are several real-world cases where largevolume heterogeneous concrete materials have been used together.From the enginee... A combined dam structure using different concrete materials offers many practical benefits.There are several real-world cases where largevolume heterogeneous concrete materials have been used together.From the engineering design standpoint,it is crucial to understand the deformation coordination characteristics and mechanical properties of large-volume heterogeneous concrete,which affect dam safety and stability.In this study,a large dam facility was selected for a case study,and various design schemes of the combined dam structure were developed by changing the configurations of material zoning and material types for a given dam shape.Elastoplastic analysis of the damfoundation-reservoir system for six schemes was carried out under dynamic conditions,in which the concrete damaged plasticity(CDP)model,the Lagrangian finite element formulation,and a surface-to-surface contact model were utilized.To evaluate the mechanical properties of zoning interfaces and coordination characteristics,the vertical distribution of the first principal stress at the longitudinal joint was used as the critical index of deformation coordination control,and the overall deformation and damage characteristics of the dam were also investigated.Through a comparative study of the design schemes,an optimal scheme of the combined dam structure was identified:large-volume roller-compacted concrete(RCC)is recommended for the dam body upstream of the longitudinal joint,and high-volume fly ash conventional concrete(CC)for the dam body downstream of the longitudinal joint.This study provides engineers with a reference basis for combined dam structure design. 展开更多
关键词 Combined dam structure deformation coordination CC-RCC Dynamic response Finite element simulation Concrete damaged plasticity(CDP)model
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Nonlinear formulation for flexible multibody system with large deformation 被引量:11
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作者 Jinyang Liu Jiazhen Hong 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2007年第1期111-119,共9页
In this paper, nonlinear modeling for flexible multibody system with large deformation is investigated. Absolute nodal coordinates are employed to describe the displacement, and variational motion equations of a flexi... In this paper, nonlinear modeling for flexible multibody system with large deformation is investigated. Absolute nodal coordinates are employed to describe the displacement, and variational motion equations of a flexible body are derived on the basis of the geometric nonlinear theory, in which both the shear strain and the transverse normal strain are taken into account. By separating the inner and the boundary nodal coordinates, the motion equations of a flexible multibody system are assembled. The advantage of such formulation is that the constraint equations and the forward recursive equations become linear because the absolute nodal coordinates are used. A spatial double pendulum connected to the ground with a spherical joint is simulated to investigate the dynamic performance of flexible beams with large deformation. Finally, the resultant constant total energy validates the present formulation. 展开更多
关键词 Flexible multibody system Large deformation Absolute nodal coordinate formulation
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Geometric Nonlinear Formulation for a Rectangular Plate with Large Deformation 被引量:1
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作者 刘锦阳 马易志 洪嘉振 《Journal of Shanghai Jiaotong university(Science)》 EI 2007年第6期831-837,844,共8页
Absolute nodal coordinate formulation for a rectangular plate with large deformation was improved. Based on nonlinear elastic theory, a precise strain expression is used to derive the equations of motion. Both shear s... Absolute nodal coordinate formulation for a rectangular plate with large deformation was improved. Based on nonlinear elastic theory, a precise strain expression is used to derive the equations of motion. Both shear strain and transverse normal strain are taken into account. Different from the previous absolute nodal coordinate formulation, the absolute nodal coordinates, which describe the displacement and slope of the element nodes, are separated into three parts: the absolute nodal coordinates in X, Y and Z directions, respectively, so that the dimension of the mass, stiffness and force matrices is reduced. Furthermore, by using constant matrices, which can be calculated and saved before simulation, the nonlinear stiffness matrices can be calculated by matrix multiplication for each time step, so that the computational efficiency can be improved. Finally, simulation example of a rectangular plate with large deformation was used to verify the accuracy and efficiency of the present formulation. 展开更多
关键词 RECTANGULAR PLATE ABSOLUTE NODAL coordinATE FORMULATION large deformation
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Surrounding rock deformation analysis of underground caverns with multi-body finite element method
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作者 Wan-jin LIANG Chao SU Fei WANG Xiao-jun TANG 《Water Science and Engineering》 EI CAS 2009年第3期71-77,共7页
Discontinuous deformation problems are common in rock engineering. Numerical analysis methods based on system models of the discrete body can better solve these problems. One of the most effective solutions is discont... Discontinuous deformation problems are common in rock engineering. Numerical analysis methods based on system models of the discrete body can better solve these problems. One of the most effective solutions is discontinuous deformation analysis (DDA) method, but the DDA method brings about rock embedding problems when it uses the strain assumption in elastic deformation and adopts virtual springs to simulate the contact problems. The multi-body finite element method (FEM) proposed in this paper can solve the problems of contact and deformation of blocks very well because it integrates the FEM and multi-body system dynamics theory. It is therefore a complete method for solving discontinuous deformation problems through balance equations of the contact surface and for simulating the displacement of whole blocks. In this study, this method was successfully used for deformation analysis of underground caverns in stratified rock. The simulation results indicate that the multi-body FEM can show contact forces and the stress states on contact surfaces better than DDA, and that the results calculated with the multi-body FEM are more consistent with engineering practice than those calculated with DDA method. 展开更多
关键词 multi-body finite element method discontinuous deformation surrounding rockdeformation elastic contact coordination displacement
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Deforming analysis of sheet metal based on stereo vision and coordinate grid
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作者 HongqinWei DehongYu +1 位作者 XueyuRuan YouqingWang 《Journal of University of Science and Technology Beijing》 CSCD 2004年第2期178-182,共5页
A new approach based on stereo vision technology is introduced to analyzesheet metal deformation. By measuring the deformed circle grids that are printed on the sheetsurface before forming, the strain distribution of ... A new approach based on stereo vision technology is introduced to analyzesheet metal deformation. By measuring the deformed circle grids that are printed on the sheetsurface before forming, the strain distribution of the workpiece is obtained. The measurement andanalysis results can be used to verify numerical simulation results and guide production. To getgood accuracy, some new techniques are employed: camera calibration based on genetic algorithm,feature abstraction based on self-adaptive technology, image matching based on structure feature andcamera modeling pre-constrains, and parameter calculation based on curve and surface optimization.The experimental values show that the approach proposed is rational and practical, which can providebetter measurement accuracy with less time than the conventional method. 展开更多
关键词 sheet metal forming deforming analysis stereo vision coordinate grid
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Application of the quadrilateral area coordinate method:a new element for laminated composite plate bending problems 被引量:6
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作者 Song Cen Xiangrong Fu +2 位作者 Yuqiu Long Hongguang Li Zhenhan Yao 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2007年第5期561-575,共15页
Recently, some new quadrilateral finite elements were successfully developed by the Quadrilateral Area Coordinate (QAC) method. Compared with those traditional models using isoparametric coordinates, these new model... Recently, some new quadrilateral finite elements were successfully developed by the Quadrilateral Area Coordinate (QAC) method. Compared with those traditional models using isoparametric coordinates, these new models are less sensitive to mesh distortion. In this paper, a new displacement-based, 4-node 20-DOF (5-DOF per node) quadrilateral bending element based on the first-order shear deformation theory for analysis of arbitrary laminated composite plates is presented. Its bending part is based on the element AC-MQ4, a recent-developed high-performance Mindlin-Reissner plate element formulated by QAC method and the generalized conforming condition method; and its in-plane displacement fields are interpolated by bilinear shape functions in isoparametric coordinates. Furthermore, the hybrid post-rocessing procedure, which was firstly proposed by the authors, is employed again to improve the stress solutions, especially for the transverse shear stresses. The resulting element, denoted as AC-MQ4-LC, exhibits excellent performance in all linear static and dynamic numerical examples. It demonstrates again that the QAC method, the generalized conforming condition method, and the hybrid post-processing procedure are efficient tools for developing simple, effective and reliable finite element models. 展开更多
关键词 Quadrilateral Area coordinate (QAC) Finite element Laminated composite plate First-order shear deformation theory (FSDT) Hybrid post-processing procedure
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3D finite element analysis on pile-soil interaction of passive pile group 被引量:6
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作者 赵明华 刘敦平 +1 位作者 张玲 蒋冲 《Journal of Central South University of Technology》 EI 2008年第1期75-80,共6页
The interaction between pile and soft soil of the passive pile group subjected to soil movement was analyzed with three-dimensional finite element model by using ANSYS software. The soil was assumed to be elastic-plas... The interaction between pile and soft soil of the passive pile group subjected to soil movement was analyzed with three-dimensional finite element model by using ANSYS software. The soil was assumed to be elastic-plastic complying with the Drucker-Prager yield criterion in the analysis. The large displacement of soil was considered and contact elements were used to evaluate the interaction between pile and soil. The influences of soil depth of layer and number of piles on the lateral pressure of the pile were investigated, and the lateral pressure distributions on the (2×1) pile group and on the (2×2) pile group were compared. The results show that the adjacent surcharge may result in significant lateral movement of the soft soil and considerable pressure on the pile. The pressure acting on the row near the surcharge is higher than that on the other row, due to the "barrier" and arching effects in pile groups. The passive load and its distribution should be taken into account in the design of the passive piles. 展开更多
关键词 pile-soil interaction passive pile group soft soil lateral pressure deformation 3D finite element analysis
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Coordinated grain boundary deformation governed nanograin annihilation in shear cycling 被引量:3
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作者 Yingbin Chen Qishan Huang +4 位作者 Qi Zhu Kexing Song Yanjun Zhou Haofei Zhou Jiangwei Wang 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2021年第27期180-191,共12页
Grain growth and shrinkage are essential to the thermal and mechanical stability of nanocrystalline metals,which are assumed to be governed by the coordinated deformation between neighboring grain boundaries(GBs)in th... Grain growth and shrinkage are essential to the thermal and mechanical stability of nanocrystalline metals,which are assumed to be governed by the coordinated deformation between neighboring grain boundaries(GBs)in the nanosized grains.However,the dynamics of such coordination has rarely been reported,especially in experiments.In this work,we systematically investigate the atomistic mechanism of coordinated GB deformation during grain shrinkage in an Au nanocrystal film through combined stateof-the-art in situ shear testing and atomistic simulations.We demonstrate that an embedded nanograin experiences shrinkage and eventually annihilation during a typical shear loading cycle.The continuous grain shrinkage is accommodated by the coordinated evolution of the surrounding GB network via dislocation-mediated migration,while the final grain annihilation proceeds through the sequential dislocation-annihilation-induced grain rotation and merging of opposite GBs.Both experiments and simulations show that stress distribution and GB structure play important roles in the coordinated deformation of different GBs and control the grain shrinkage/annihilation under shear loading.Our findings establish a mechanistic relation between coordinated GB deformation and grain shrinkage,which reveals a general deformation phenomenon in nanocrystalline metals and enriches our understanding on the atomistic origin of structural stability in nanocrystalline metals under mechanical loading. 展开更多
关键词 Nanocrystalline metals Grain shrinkage and annihilation Grain boundary migration Grain rotation coordinated deformation
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Contact dynamics of elasto-plastic thin beams simulated via absolute nodal coordinate formulation 被引量:4
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作者 Qing-Tao Wang Qiang Tian Hai-Yan Hu 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2016年第3期525-534,共10页
Under the frame of multibody dynamics, the contact dynamics of elasto-plastic spatial thin beams is numerically studied by using the spatial thin beam elements of absolute nodal coordinate formulation(ANCF). The int... Under the frame of multibody dynamics, the contact dynamics of elasto-plastic spatial thin beams is numerically studied by using the spatial thin beam elements of absolute nodal coordinate formulation(ANCF). The internal force of the elasto-plastic spatial thin beam element is derived under the assumption that the plastic strain of the beam element depends only on its longitudinal deformation.A new body-fixed local coordinate system is introduced into the spatial thin beam element of ANCF for efficient contact detection in the contact dynamics simulation. The linear isotropic hardening constitutive law is used to describe the elasto-plastic deformation of beam material, and the classical return mapping algorithm is adopted to evaluate the plastic strains. A multi-zone contact approach of thin beams previously proposed by the authors is also introduced to detect the multiple contact zones of beams accurately, and the penalty method is used to compute the normal contact force of thin beams in contact. Four numerical examples are given to demonstrate the applicability and effectiveness of the proposed elasto-plastic spatial thin beam element of ANCF for flexible multibody system dynamics. 展开更多
关键词 Elasto-plastic deformation Linear isotropic hardening constitutive law Absolute nodal coordinate formulation(ANCF) Thin beam multi-zone contact dynamics
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Numerical Investigation on Dynamics of the Tendon System of A TLP by Applying Absolute Nodal Coordinate Formulation 被引量:2
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作者 Luu Quang HUNG KANG Zhuang +1 位作者 ZHANG Cheng JIE Li-shao 《China Ocean Engineering》 SCIE EI CSCD 2021年第3期384-397,共14页
In the present study,the dynamics of the tendon system of a tension-leg platform(TLP)is investigated through the absolute nodal coordinate formulation(ANCF).Based on the energy conversion principle,the stiffness,gener... In the present study,the dynamics of the tendon system of a tension-leg platform(TLP)is investigated through the absolute nodal coordinate formulation(ANCF).Based on the energy conversion principle,the stiffness,generalized elastic force,external load and mass matrices of the element are deduced to perform the element assembling by using the finite element method.Then the motion equation of the tendon/riser is established.In this study,the TLP in the International Ship Structures Committee(ISSC)model under the first and second wave forces is considered as the case study.The simulation is performed in the MATLAB environment.Moreover,the accuracy and reliability of the programs are verified for cases of beam model with theoretical solutions.It is found that the motion response of tendons is affected by the TLP movement and environmental load,simultaneously.Then,the motion response is calculated using the SESAM software and exported as the boundary of ANCF tendons.Finally,the static and dynamic characteristics of the four tendons of ISSC TLP are analyzed systematically by the ANCF method.Performed analysis proves the effectiveness and feasibility of the ANCF method.It is concluded that the proposed method is a powerful scheme for calculating the dynamics of tendon/riser in the field of ocean engineering. 展开更多
关键词 Absolute nodal coordinate formulation(ANCF) tendon/riser TLP platform large deformation top and middle nodes wave direction
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An exact nonlinear hybrid-coordinate formulation for flexible multibody systems 被引量:10
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作者 Jinyang Liu Jiazhen Hong LinCui 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2007年第6期699-706,共8页
The previous low-order approximate nonlinear formulations succeeded in capturing the stiffening terms, but failed in simulation of mechanical systems with large deformation due to the neglect of the high-order deforma... The previous low-order approximate nonlinear formulations succeeded in capturing the stiffening terms, but failed in simulation of mechanical systems with large deformation due to the neglect of the high-order deformation terms. In this paper, a new hybrid-coordinate formulation is proposed, which is suitable for flexible multibody systems with large deformation. On the basis of exact strain- displacement relation, equations of motion for flexible multi-body system are derived by using virtual work principle. A matrix separation method is put forward to improve the efficiency of the calculation. Agreement of the present results with those obtained by absolute nodal coordinate formulation (ANCF) verifies the correctness of the proposed formulation. Furthermore, the present results are compared with those obtained by use of the linear model and the low-order approximate nonlinear model to show the suitability of the proposed models. 展开更多
关键词 Nonlinear hybrid-coordinate formulation Flexible multibody systems Large deformation
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基于DEFORM的金属焊丝盘线材弯曲回弹研究
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作者 刘洋 邢建国 《青岛大学学报(工程技术版)》 CAS 2017年第4期81-85,共5页
针对线材弯曲成型所存在的回弹问题,本文基于DEFORM软件,对梅花骨金属焊丝盘线材弯曲回弹进行分析。建立了金属焊丝盘线材4个部位的模型,对回弹量数据进行分析,提取模拟分析中线材的坐标,并通过坐标变换,计算回弹量的大小。计算结果表明... 针对线材弯曲成型所存在的回弹问题,本文基于DEFORM软件,对梅花骨金属焊丝盘线材弯曲回弹进行分析。建立了金属焊丝盘线材4个部位的模型,对回弹量数据进行分析,提取模拟分析中线材的坐标,并通过坐标变换,计算回弹量的大小。计算结果表明,通过模型a,c和d弯曲回弹后的坐标变化,得其回弹角分别为0.132°,4.103°,2.825°,由于模型a的回弹量较小,可以忽略不计。该研究为模具的进一步优化提供了理论依据。 展开更多
关键词 金属焊丝盘 线材 成型精度 deform 回弹分析 坐标变换 回弹角
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Integrability of a New Type of Deformed XXZ Model
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作者 CAO Li-Ke KE San-Min YUE Rui-Hong 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第4X期671-674,共4页
A new type of deformed XXZ model was constructed and diagonalized by the coordinate Bethe ansatz method. We obtained the energy and the Bethe ansatz equations of the model and also discussed some thermodynamics of the... A new type of deformed XXZ model was constructed and diagonalized by the coordinate Bethe ansatz method. We obtained the energy and the Bethe ansatz equations of the model and also discussed some thermodynamics of the model. 展开更多
关键词 deformed XXZ model THERMODYNAMICS coordinate Bethe ansatz
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Coordinated deformation control technologies for the high sidewall—bottom transfixion zone of large underground hydro-powerhouses
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作者 Qi-xiang FAN Zhi-yun DENG +3 位作者 Peng LIN Guo LI Ji-lin FU Wei HE 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2022年第7期543-563,共21页
It is imperative to understand the spatial and temporal coordination deformation mechanism and develop targeted deformation control technologies for high sidewall—bottom transfixion(HSBT)zones to guarantee the stabil... It is imperative to understand the spatial and temporal coordination deformation mechanism and develop targeted deformation control technologies for high sidewall—bottom transfixion(HSBT)zones to guarantee the stability of rock surrounding underground hydro-powerhouses under complex geological conditions.In this study,the spatial and temporal coordinated deformation control of HSBT zones was addressed from the aspects of the deformation mechanism,failure characteristics,and control requirements,and some coordinated deformation control technologies were proposed.On this basis,a case study was conducted on the deformation control of the HSBT zone of the underground powerhouse at the Wudongde hydropower station,China.The results showed that the relationship between excavation and support,and the mismatch of deformation and support of the surrounding rock mass in the HSBT zone of underground caverns with a large span and high in-situ stress can be appropriately handled.The solution requires proper excavation and construction procedures,fine blasting control,composite and timely support,and real-time monitoring and dynamic feedback.The technologies proposed in this study will ensure the safe,high-quality,and orderly construction of the Baihetan and Wudongde underground caverns,and can be applied to other similar projects. 展开更多
关键词 Underground powerhouse coordinated deformation mechanism High sidewall-bottom transfixion(HSBT) Cavern group Control technology
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公铁两用大跨度斜拉桥-无砟轨道体系变形适应性研究 被引量:4
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作者 盛兴旺 郭舜哲 +2 位作者 郑纬奇 朱志辉 胡辉跃 《铁道科学与工程学报》 EI CAS CSCD 北大核心 2024年第3期1058-1067,共10页
高速铁路大跨度斜拉桥结构变形受其复杂服役环境影响显著,而无砟轨道对工后变形的调整能力有限,因此大跨度斜拉桥的复杂变形条件将直接影响其上无砟轨道结构的适应性。以沪渝蓉高铁长江北支公铁两用大跨度斜拉桥应用无砟轨道为工程背景... 高速铁路大跨度斜拉桥结构变形受其复杂服役环境影响显著,而无砟轨道对工后变形的调整能力有限,因此大跨度斜拉桥的复杂变形条件将直接影响其上无砟轨道结构的适应性。以沪渝蓉高铁长江北支公铁两用大跨度斜拉桥应用无砟轨道为工程背景,建立无砟轨道-大跨度斜拉桥一体化精细空间有限元模型,分析铁路、公路以及温度等多种荷载联合作用下大跨度斜拉桥-无砟轨道体系平顺性、无缝线路稳定性和无砟轨道层间变形协调性,从而对大跨度公铁两用钢桁梁斜拉桥-无砟轨道体系变形适应性开展深入研究。结果表明:在运营荷载及温度荷载最不利组合作用下,大跨度斜拉桥主梁线形平顺,变形平缓,桥梁整体刚度较好,桥上无砟轨道几何形位可以满足静态验收标准;大跨度斜拉桥上无缝线路的强度和稳定性满足要求,扣件工作性能良好,钢轨伸缩调节器的设置可有效释放梁端钢轨的纵向应力;无砟轨道层间设置橡胶隔离层且不跨主梁桁架节间的布置方式可提高大跨度斜拉桥上无砟轨道的变形协调性能,使得桥上无砟轨道层间始终处于受压状态,达到“隔而不离”的桥上轨道层间理想服役状态;大跨度公铁两用钢桁梁斜拉桥-无砟轨道体系变形适应性良好。本文研究成果可为公铁两用大跨度钢桁梁斜拉桥上无砟轨道的应用提供技术参考。 展开更多
关键词 公铁两用大跨度斜拉桥 无砟轨道 无缝线路 变形适应性 稳定性 平顺性 协调性
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INVERSE DDA OF A SYSTEM OF BLOCKS IN SPHERE COORDINATES
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作者 Wu Yun,Wang Hui,Zhou Shuoyu and Shi Shunying (Institute of Seismology, CEA, Wuhan 430071, China) 《大地测量与地球动力学》 CSCD 2003年第B12期30-33,49,共5页
In accordance with the geometric equations of elastic mechanics in the sphere coordinates, the displacement equation of blocks on asphere consisting of 6 deforming parameters is developed. The formula for distance bet... In accordance with the geometric equations of elastic mechanics in the sphere coordinates, the displacement equation of blocks on asphere consisting of 6 deforming parameters is developed. The formula for distance between blocks is derived under the supposition that all block boundaries are prime arcs. The kinematic constraint and the penalty function for reasonable contact between blocks are developed. The normal equations and their coefficient matrix, based on the Least Squares Principle, are derived. The problem of adjudging penetration between blocks is discussed, and a solution is proposed. 展开更多
关键词 不连续变形分析 DDA 地壳运动 板快系统 球坐标 运动约束 逆向方程 贯穿评价
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基于微处理器和多通信方式的大坝变形智能监测仪器的设计与实现 被引量:2
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作者 周芳芳 张锋 +1 位作者 杜泽东 胡超 《长江科学院院报》 CSCD 北大核心 2024年第2期167-172,180,共7页
变形监测作为大坝安全状态感知的重要手段,具有测值直观、能全面反映大坝安全状态等特点,对保障大坝长期安全稳定运行具有重要的意义。目前大坝水平位移自动化监测主要使用引张线法、真空激光准直法及垂线法。尽管CCD垂线坐标仪已在大... 变形监测作为大坝安全状态感知的重要手段,具有测值直观、能全面反映大坝安全状态等特点,对保障大坝长期安全稳定运行具有重要的意义。目前大坝水平位移自动化监测主要使用引张线法、真空激光准直法及垂线法。尽管CCD垂线坐标仪已在大坝工程实践中广泛应用,可该仪器存在不支持现场配置、现场实时数据读取等不足,且无直接远程交互功能,需要接入其他采集装置或转接设备才能进行远程通信。本文设计的智能式CCD垂线坐标仪运用微处理器及以太网接口,不需要接入其他采集设备,可直接接入软件系统,解决了仪器集成复杂、传统通信方式不稳定等问题;并运用蓝牙通信和智能手机APP,解决了现场参数配置、实时采集显示的问题;提出了一种反馈式自适应调光技术,提高了仪器的自适应性和稳定性。 展开更多
关键词 大坝变形监测 线阵CCD 垂线坐标仪 以太网 蓝牙通信
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考虑衬砌截面协调变形约束的既有隧道受盾构下穿施工影响的Fourier能量变分解 被引量:1
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作者 张治国 沃巍 +2 位作者 朱正国 韩凯航 孙苗苗 《岩土力学》 EI CAS CSCD 北大核心 2024年第5期1397-1411,1422,共16页
目前关于新建盾构开挖诱发既有地铁隧道变形的理论研究,大多将既有隧道简化为不含接头的Euler-Bernoulli梁,而忽视了衬砌截面的剪切变形与管片接头的局部刚度削弱。此外,既有地基模型理论较少考虑衬砌管片与接触土体的协调变形约束。首... 目前关于新建盾构开挖诱发既有地铁隧道变形的理论研究,大多将既有隧道简化为不含接头的Euler-Bernoulli梁,而忽视了衬砌截面的剪切变形与管片接头的局部刚度削弱。此外,既有地基模型理论较少考虑衬砌管片与接触土体的协调变形约束。首先,采用Loganathan-Polous公式计算盾构开挖诱发的土体自由位移场,并将既有隧道视为考虑剪切变形的Timoshenko梁,基于沿轴线变化的抗弯与剪切刚度函数来描述管片接头的局部削弱作用;然后,结合能量变分原理与连续弹性体Mindlin解,建立考虑衬砌截面协同变形约束的隧道位移控制方程,将盾构开挖诱发的附加荷载施加于既有隧道,并使用Fourier级数方法求解既有隧道纵向变形;最后,将Fourier能量变分解与3组工程实测数据进行对比验证,取得了较好的一致性。此外,考虑隧道抗弯刚度、剪切刚度、接头刚度削弱作用、土体参数与隧道空间位置等因素的共同影响,使用抗弯系数、剪切系数及接头系数进行敏感性分析。结果表明,考虑截面变形协调约束的理论解更为符合实际,不考虑变形协调约束所得隧道位移结果偏大;衬砌接头局部刚度的削弱作用将造成隧道弯矩沿轴线在接头处发生明显锯齿状突变;抗弯系数与剪切系数的增长均导致隧道结构所受弯矩降低;剪切系数由低到高的增长将导致隧道变形模式发生“弯曲控制-弯剪混合-剪切控制”三阶段变化;隧道变形模式进入“剪切控制”阶段的过程中,抗弯刚度的变化对隧道内力影响逐渐降低;接头系数的增长将造成隧道所受弯矩降低,但隧道抗弯刚度较大时其影响逐渐减弱。 展开更多
关键词 盾构隧道 截面协调变形 接头刚度削弱 隧道剪切变形 TIMOSHENKO梁 Fourier能量变分
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砂土压缩变形传感光缆耦合试验分析与预测模型研究
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作者 许时昂 张平松 +2 位作者 程刚 吴海波 张涛 《岩土力学》 EI CAS CSCD 北大核心 2024年第5期1570-1582,共13页
灾害监测、预测是地质与岩土工程领域一项极为重要的任务。分布式光纤传感技术凭借其连续、实时、抗干扰、稳定性好等优点在长距离、长周期、高隐蔽性、强突发性的灾害监测中发挥了显著的作用。然而,针对不同工程问题,评价与解决传感光... 灾害监测、预测是地质与岩土工程领域一项极为重要的任务。分布式光纤传感技术凭借其连续、实时、抗干扰、稳定性好等优点在长距离、长周期、高隐蔽性、强突发性的灾害监测中发挥了显著的作用。然而,针对不同工程问题,评价与解决传感光缆与被测岩土体协调变形问题,是精细化分析岩土体变形分布与研究演化规律的关键所在。利用自主研制的三维主动变形可控围压光缆-砂土耦合试验装置,探究了0~4.0MPa围压条件下金属基索传感光缆与粗砂介质压缩变形的协调性问题。试验结果表明:低围压条件下金属基索传感光缆与砂土压缩变形协调性较差,变形表现为非线性变化特征;随着围压增大,传感光缆与砂土耦合效果提高,变形呈现线性变化特征,当围压达到1.6MPa后,两者协调变形一致性明显提高,其形变由非线性向线性转变。基于上述变形特性,提出了一种围压曲面投影数值模型,采用非扭结边界条件的样条插值算法对非试验数据实际位移进行预测,结果表明该模型具有较好的可靠性。试验研究认为金属基索光缆用于高围压条件下砂土变形测试具有更高的准确性,研究内容可以为分布式光纤传感测试技术用于深部地层变形监测提供科学的参考依据。 展开更多
关键词 分布式光纤 岩土变形 应变传递 协调变形 数值模型
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自动检测设备高温下测试坐标修正方法 被引量:1
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作者 左宁 袁丽娟 +1 位作者 胡奇威 霍鑫 《电子工艺技术》 2024年第1期51-55,共5页
硅晶圆半导体芯片在进行晶圆级电性能测量时,往往需要模拟芯片实际工作时的工作环境,如温度、湿度、气压。在自动探针台上进行高温环境模拟测试时,由于高温会导致测针、晶圆片和承片卡盘产生一定程度的形变,从而使得芯片上测试Pad位置... 硅晶圆半导体芯片在进行晶圆级电性能测量时,往往需要模拟芯片实际工作时的工作环境,如温度、湿度、气压。在自动探针台上进行高温环境模拟测试时,由于高温会导致测针、晶圆片和承片卡盘产生一定程度的形变,从而使得芯片上测试Pad位置坐标发生偏移,这种情况下,测试系统需要对形变后的测试点坐标进行修正。提出了一种基于机器视觉自动图形识别的在线修正测试点坐标偏移方法,用以解决自动探针台在高温环境下进行电性能测试时的测试坐标修正难题。 展开更多
关键词 探针测试系统 坐标修正 高温形变
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