期刊文献+
共找到339篇文章
< 1 2 17 >
每页显示 20 50 100
Unified analysis for stabilized methods of low-order mixed finite elements for stationary Navier-Stokes equations 被引量:2
1
作者 陈刚 冯民富 何银年 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2013年第8期953-970,共18页
A unified analysis is presented for the stabilized methods including the pres- sure projection method and the pressure gradient local projection method of conforming and nonconforming low-order mixed finite elements f... A unified analysis is presented for the stabilized methods including the pres- sure projection method and the pressure gradient local projection method of conforming and nonconforming low-order mixed finite elements for the stationary Navier-Stokes equa- tions. The existence and uniqueness of the solution and the optimal error estimates are proved. 展开更多
关键词 Navier-Stokes equation Ladyzhenskaya-Babu^ka-Brezzi (LBB) condition low-order finite element pressure projection method pressure gradient local projectionmethod
下载PDF
Virtual rutting test of asphalt mixture using discrete element method 被引量:6
2
作者 张德育 黄晓明 高英 《Journal of Southeast University(English Edition)》 EI CAS 2012年第2期215-220,共6页
In order to investigate the permanent deformation behavior of asphalt mixtures from discontinuity, the virtual rutting test of asphalt mixtures is developed by the discrete element method (DEM). A digital specimen g... In order to investigate the permanent deformation behavior of asphalt mixtures from discontinuity, the virtual rutting test of asphalt mixtures is developed by the discrete element method (DEM). A digital specimen generation procedure considering aggregate gradation and irregular shape is developed based on the probability theory and the Monte Carlo method. The virtual rutting test is then conducted based on the generated digital specimen. In addition, on the basis of the time-temperature superposition (TTS) principle, a calculation method is used to reduce the computation time of the virtual rutting test. The simulation results are compared with the laboratory measurements. The results show that the calculation method based on the TFS principle in the discrete element (DE) viscoelastic model can significantly reduce the computation time. The deformation law of asphalt mixtures in the virtual rutting test is similar to the laboratory measurements, and the deformation and the dynamic stability of the virtual rutting test are slightly greater than the laboratory measurements. The two-dimensional virtual rutting test can predict the permanent deformation performance of asphalt mixtures. 展开更多
关键词 asphalt mixture permanent deformation discrete element method virtual rutting test
下载PDF
Virtual fracture test of asphalt mixture based on discrete element method 被引量:6
3
作者 陈俊 黄晓明 《Journal of Southeast University(English Edition)》 EI CAS 2009年第4期518-522,共5页
In order to study fracture behaviors of asphalt mixtures, virtual tests of the two-dimensional(2D) microstructure based on the discrete element method( DEM) are designed. The virtual structure of the 2D digital sp... In order to study fracture behaviors of asphalt mixtures, virtual tests of the two-dimensional(2D) microstructure based on the discrete element method( DEM) are designed. The virtual structure of the 2D digital specimen of asphalt mixture is generated based on a particle generation program, in which the gradation and the irregular shapes of aggregates are considered. With the 2D digital specimens, a DEM-based mixture model is established and center-point beam fracture simulation tests are conducted by the DEM. Meanwhile, a series of calibration tests are carried out in laboratory to evaluate the DEM model and validate the methods of virtual fracture tests. The test results indicate that the fracture intensity of asphalt mixtures predicted by the DEM matches very well with the intensity obtained in laboratory. It is concluded that the microstructural virtual tests can be used as a supplemental tool to evaluate fracture properties of asphalt mixtures. 展开更多
关键词 asphalt mixture FRACTURE discrete element method virtual test
下载PDF
Microstructure modeling and virtual test of asphalt mixture based on three-dimensional discrete element method 被引量:3
4
作者 马涛 张德育 +2 位作者 张垚 赵永利 黄晓明 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第6期1525-1534,共10页
The objective of this work is to model the microstructure of asphalt mixture and build virtual test for asphalt mixture by using Particle Flow Code in three dimensions(PFC^(3D))based on three-dimensional discrete elem... The objective of this work is to model the microstructure of asphalt mixture and build virtual test for asphalt mixture by using Particle Flow Code in three dimensions(PFC^(3D))based on three-dimensional discrete element method.A randomly generating algorithm was proposed to capture the three-dimensional irregular shape of coarse aggregate.And then,modeling algorithm and method for graded aggregates were built.Based on the combination of modeling of coarse aggregates,asphalt mastic and air voids,three-dimensional virtual sample of asphalt mixture was modeled by using PFC^(3D).Virtual tests for penetration test of aggregate and uniaxial creep test of asphalt mixture were built and conducted by using PFC^(3D).By comparison of the testing results between virtual tests and actual laboratory tests,the validity of the microstructure modeling and virtual test built in this study was verified.Additionally,compared with laboratory test,the virtual test is easier to conduct and has less variability.It is proved that microstructure modeling and virtual test based on three-dimensional discrete element method is a promising way to conduct research of asphalt mixture. 展开更多
关键词 asphalt mixture microstructure modeling virtual test discrete element method three-dimensional method
下载PDF
Thermal Analysis of Turbine Blades with Thermal Barrier Coatings Using Virtual Wall Thickness Method
5
作者 Linchuan Liu Jian Wu +4 位作者 Zhongwei Hu Xiaochao Jin Pin Lu Tao Zhang Xueling Fan 《Computer Modeling in Engineering & Sciences》 SCIE EI 2023年第2期1219-1236,共18页
Avirtual wall thicknessmethod is developed to simulate the temperature field of turbine bladeswith thermal barrier coatings(TBCs),to simplify the modeling process and improve the calculation efficiency.The results sho... Avirtual wall thicknessmethod is developed to simulate the temperature field of turbine bladeswith thermal barrier coatings(TBCs),to simplify the modeling process and improve the calculation efficiency.The results show that the virtualwall thickness method can improve themesh quality by 20%,reduce the number ofmeshes by 76.7%and save the calculation time by 35.5%,compared with the traditional real wall thickness method.The average calculation error of the two methods is between 0.21%and 0.93%.Furthermore,the temperature at the blade leading edge is the highest and the average temperature of the blade pressure surface is higher than that of the suction surface under a certain service condition.The blade surface temperature presents a high temperature at both ends and a low temperature in themiddle height when the temperature of incoming gas is uniformand constant.The thermal insulation effect of TBCs is the worst near the air film hole,and the best at the blade leading edge.According to the calculated temperature field of the substrate-coating system,the highest thermal insulation temperature of the TC layer is 172.01 K,and the thermal insulation proportions of TC,TGO and BC are 93.55%,1.54%and 4.91%,respectively. 展开更多
关键词 Turbine blade thermal analysis thermal barrier coatings finite element method virtual wall thickness
下载PDF
A novel virtual node method for polygonal elements 被引量:1
6
作者 唐旭海 吴圣川 +1 位作者 郑超 张建海 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2009年第10期1233-1246,共14页
A novel polygonal finite element method (PFEM) based on partition of unity is proposed, termed the virtual node method (VNM). To test the performance of the present method, numerical examples are given for solid m... A novel polygonal finite element method (PFEM) based on partition of unity is proposed, termed the virtual node method (VNM). To test the performance of the present method, numerical examples are given for solid mechanics problems. With a polynomial form, the VNM achieves better results than those of traditional PFEMs, including the Wachspress method and the mean value method in standard patch tests. Compared with the standard triangular FEM, the VNM can achieve better accuracy. With the ability to construct shape functions on polygonal elements, the VNM provides greater flexibility in mesh generation. Therefore, several fracture problems are studied to demonstrate the potential implementation. With the advantage of the VNM, the convenient refinement and remeshing strategy are applied. 展开更多
关键词 virtual node method polygonal finite element method partition of unity crack propagation
下载PDF
Virtual Element Discretization of Optimal Control Problem Governed by Brinkman Equations
7
作者 Yanwei Li 《Engineering(科研)》 CAS 2023年第2期114-133,共20页
In this paper, we discuss virtual element method (VEM) approximation of optimal control problem governed by Brinkman equations with control constraints. Based on the polynomial projections and variational discretizati... In this paper, we discuss virtual element method (VEM) approximation of optimal control problem governed by Brinkman equations with control constraints. Based on the polynomial projections and variational discretization of the control variable, we build up the virtual element discrete scheme of the optimal control problem and derive the discrete first order optimality system. A priori error estimates for the state, adjoint state and control variables in L<sup>2</sup> and H<sup>1</sup> norm are derived. The theoretical findings are illustrated by the numerical experiments. 展开更多
关键词 virtual element method Optimal Control Problem Brinkman Equations A Priori Error Estimate
下载PDF
A Virtual Boundary Element Method for Three-Dimensional Inverse Heat Conduction Problems in Orthotropic Media
8
作者 Xu Liu Guojian Shao +2 位作者 Xingxing Yue Qingbin Yang Jingbo Su 《Computer Modeling in Engineering & Sciences》 SCIE EI 2018年第11期189-211,共23页
This paper aims to apply a virtual boundary element method(VBEM)to solve the inverse problems of three-dimensional heat conduction in orthotropic media.This method avoids the singular integrations in the conventional ... This paper aims to apply a virtual boundary element method(VBEM)to solve the inverse problems of three-dimensional heat conduction in orthotropic media.This method avoids the singular integrations in the conventional boundary element method,and can be treated as a potential approach for solving the inverse problems of the heat conduction owing to the boundary-only discretization and semi-analytical algorithm.When the VBEM is applied to the inverse problems,the numerical instability may occur if a virtual boundary is not properly chosen.The method encounters a highly illconditioned matrix for the larger distance between the physical boundary and the virtual boundary,and otherwise is hard to avoid the singularity of the source point.Thus,it must adopt an appropriate regularization method to deal with the ill-posed systems of inverse problems.In this study,the VBEM and different regularization techniques are combined to model the inverse problem of three-dimensional heat conduction in orthotropic media.The proper regularization techniques not only make the virtual boundary to be allocated freer,but also solve the ill-conditioned equation of the inverse problem.Numerical examples demonstrate that the proposed method is efficient,accurate and numerically stable for solving the inverse problems of three-dimensional heat conduction in orthotropic media. 展开更多
关键词 virtual BOUNDARY element method Tikhonov REGULARIZATION threedimensional heat conduction INVERSE problem ORTHOTROPIC media.
下载PDF
ERROR ANALYSIS OF THE SECOND-ORDER SERENDIPITY VIRTUAL ELEMENT METHOD FOR SEMILINEAR PSEUDO-PARABOLIC EQUATIONS ON CURVED DOMAINS
9
作者 Yang Xu Zhenguo Zhou Jingjun Zhao 《Journal of Computational Mathematics》 SCIE CSCD 2024年第6期1743-1776,共34页
The second-order serendipity virtual element method is studied for the semilinear pseudo-parabolic equations on curved domains in this paper.Nonhomogeneous Dirichlet boundary conditions are taken into account,the exis... The second-order serendipity virtual element method is studied for the semilinear pseudo-parabolic equations on curved domains in this paper.Nonhomogeneous Dirichlet boundary conditions are taken into account,the existence and uniqueness are investigated for the weak solution of the nonhomogeneous initial-boundary value problem.The Nitschebased projection method is adopted to impose the boundary conditions in a weak way.The interpolation operator is used to deal with the nonlinear term.The Crank-Nicolson scheme is employed to discretize the temporal variable.There are two main features of the proposed scheme:(i)the internal degrees of freedom are avoided no matter what type of mesh is utilized,and(ii)the Jacobian is simple to calculate when Newton’s iteration method is applied to solve the fully discrete scheme.The error estimates are established for the discrete schemes and the theoretical results are illustrated through some numerical examples. 展开更多
关键词 Semilinear pseudo-parabolic equation Serendipity virtual element method Projection method Curved domain
原文传递
Shape optimization of plate with static and dynamic constraints via virtual laminated element 被引量:1
10
作者 李芳 徐兴 凌道盛 《Journal of Zhejiang University Science》 EI CSCD 2003年第2期202-206,共5页
The virtual laminated element method (VLEM) can resolve structural shap e optimization problems with a new method. According to the characteristics of V LEM , only some characterized layer thickness values need be def... The virtual laminated element method (VLEM) can resolve structural shap e optimization problems with a new method. According to the characteristics of V LEM , only some characterized layer thickness values need be defined as design v ariables instead of boundary node coordinates or some other parameters determini ng the system boundary. One of the important features of this method is that it is not necessary to regenerate the FE(finite element) grid during the optimizati on process so as to avoid optimization failures resulting from some distortion grid elements. Th e thickness distribution in thin plate optimization problems in other studies be fore is of stepped shape. However, in this paper, a continuous thickness distrib ution can be obtained after optimization using VLEM, and is more reasonable. Fur thermore, an approximate reanalysis method named ″behavior model technique″ ca n be used to reduce the amount of structural reanalysis. Some typical examples are offered to prove the effectiveness and practicality of the proposed method. 展开更多
关键词 Optimum design virtual laminated element method(V LEM) Behavior model technique Structural reanalysis
下载PDF
Virtual Element Formulation for Finite Strain Elastodynamics Dedicated to Professor Karl Stark Pister for his 95th birthday
11
作者 Mertcan Cihan Blaz Hudobivnik +1 位作者 Fadi Aldakheel Peter Wriggers 《Computer Modeling in Engineering & Sciences》 SCIE EI 2021年第12期1151-1180,共30页
The virtual element method(VEM)can be seen as an extension of the classical finite element method(FEM)based on Galerkin projection.It allows meshes with highly irregular shaped elements,including concave shapes.So far... The virtual element method(VEM)can be seen as an extension of the classical finite element method(FEM)based on Galerkin projection.It allows meshes with highly irregular shaped elements,including concave shapes.So far the virtual element method has been applied to various engineering problems such as elasto-plasticity,multiphysics,damage and fracture mechanics.This work focuses on the extension of the virtual element method to efficient modeling of nonlinear elasto-dynamics undergoing large deformations.Within this framework,we employ low-order ansatz functions in two and three dimensions for elements that can have arbitrary polygonal shape.The formulations considered in this contribution are based on minimization of potential function for both the static and the dynamic behavior.Generally the construction of a virtual element is based on a projection part and a stabilization part.While the stiffness matrix needs a suitable stabilization,the mass matrix can be calculated using only the projection part.For the implicit time integration scheme,Newmark-Method is used.To show the performance of the method,various two-and three-dimensional numerical examples in are presented. 展开更多
关键词 virtual element method three-dimensional dynamics finite strains
下载PDF
砌体轴心和局部受压离散元仿真在教学中的应用 被引量:1
12
作者 李涛 蔡靖 《实验技术与管理》 CAS 北大核心 2024年第3期156-164,共9页
砌体是块体和砂浆的黏结组合材料,为了让学生更好地理解砖块体和砂浆对外力的分担作用,运用离散元方法建立了砖块体团簇模型、砂浆团簇模型,进而“砌筑”了普通砖砌体数值试件,对砖砌体分别开展轴心受压和局部受压仿真。仿真复现了砌体... 砌体是块体和砂浆的黏结组合材料,为了让学生更好地理解砖块体和砂浆对外力的分担作用,运用离散元方法建立了砖块体团簇模型、砂浆团簇模型,进而“砌筑”了普通砖砌体数值试件,对砖砌体分别开展轴心受压和局部受压仿真。仿真复现了砌体受压时的应力-应变关系和破坏模式,应力峰值处伴随大量砖颗粒-砖颗粒胶结接触破坏。砌体应力主要由胶结接触承担,其中砖-砖胶结接触>砖-砂浆胶结接触>砂浆-砂浆胶结接触,砂浆主要起到连接块体的作用;法向接触力承力大于切向接触力。通过仿真教学,有助于学生建立砌体宏观力学表现受控于微观结构和微观力学的认知,加深了学生对砌体受力机理和强度的理解。 展开更多
关键词 砖砌体 轴心受压 局部受压 离散单元法 虚拟仿真
下载PDF
基于S-R和分解定理的二维几何非线性问题的虚单元法求解
13
作者 江巍 尹豪 +3 位作者 吴剑 汤艳春 李坤鹏 郑宏 《工程力学》 EI CSCD 北大核心 2024年第8期23-35,共13页
应变-旋转(Strain-Rotation,S-R)和分解定理为分析几何非线性问题提供了合理可靠的理论基础,但用有限元求解时会遇到大变形发生后的网格畸变问题。近年提出的虚单元法(Virtual element method,VEM)适用于一般的多边形网格,因此,该文尝... 应变-旋转(Strain-Rotation,S-R)和分解定理为分析几何非线性问题提供了合理可靠的理论基础,但用有限元求解时会遇到大变形发生后的网格畸变问题。近年提出的虚单元法(Virtual element method,VEM)适用于一般的多边形网格,因此,该文尝试使用一阶虚单元求解基于S-R和分解定理的二维几何非线性问题,以克服网格畸变的影响。基于重新定义的多项式位移空间基函数,推演获得一阶虚单元分析线弹性力学问题时允许位移空间向多项式位移空间的投影表达式;按照虚单元法双线性格式的计算规则,分析处理基于更新拖带坐标法和势能率原理的增量变分方程;进而建立离散系统方程及其矩阵表达形式,并编制MATLAB求解程序;采用常规多边形网格和畸变网格,应用该文算法分析均布荷载下的悬臂梁和均匀内压下的厚壁圆筒变形。结果与已有文献和ANSYS软件的对比表明:该文算法在两种网格中均可有效执行且具备足够数值精度。总体该文算法为基于S-R和分解定理的二维几何非线性问题求解提供了一种鲁棒方法。 展开更多
关键词 S-R和分解定理 虚单元法 几何非线性 网格畸变 多边形网格
下载PDF
土壤学互融互补混合式智慧教学模式改革成效
14
作者 蒲玉琳 袁大刚 +2 位作者 余海英 张锡洲 李冰 《高教学刊》 2024年第11期116-120,共5页
土壤学是理论系统性高和应用实践性强的重要专业基础课。探索基于网络信息技术的土壤学线上线下混合式教学的新型模式,对于全面推进新时代一流专业建设及一流专业人才培养至关重要。综合应用文献查阅法、问卷调查法和经验总结法,以优化... 土壤学是理论系统性高和应用实践性强的重要专业基础课。探索基于网络信息技术的土壤学线上线下混合式教学的新型模式,对于全面推进新时代一流专业建设及一流专业人才培养至关重要。综合应用文献查阅法、问卷调查法和经验总结法,以优化教学内容和变革教学策略为途径,构建土壤学“互融互补混合式智慧教学模式”。这一新型教学模式包含“思政元素、专业应用、学科前沿、行业发展”的四元融合知识体系、“课前-课中-课后”三环渐进混合式智慧教学方式、“一、二课堂互补,现实虚拟互补”的二维互补实践创新能力培养体系。模式实施以来有力地提升土壤学“一流课程”“思政示范课”建设质效,以及富有“三农”情怀、能“识土-辨土-用土-改土”的新农科复合型高级人才质量,为其他传统专业课改革提供借鉴。 展开更多
关键词 混合式智慧教学模式 四元融合知识体系 三环渐进教学方式 一、二课堂互补 现实虚拟互补
下载PDF
一种求解线弹性问题的无闭锁低阶虚拟元方法
15
作者 王晓涵 王锋 《南京师大学报(自然科学版)》 CAS 北大核心 2024年第1期1-6,共6页
研究了二维区域上线弹性问题的低阶虚拟元方法.用不连续的分段线性向量值函数增扩低阶协调虚拟元空间来构造离散空间,设计了一种离散方法,证明了能量范数下的误差是最优收敛的,和Lamé常数λ无关.最后给出数值算例验证了理论结果.
关键词 线弹性问题 低阶虚拟元方法 闭锁现象
下载PDF
基于有限元技术的疲劳裂纹扩展方法研究进展 被引量:1
16
作者 苏玉昆 马涛 +3 位作者 赵晓鑫 张光亮 朱加雷 张鹏 《力学进展》 EI CSCD 北大核心 2024年第2期308-343,共36页
疲劳裂纹是引起工程结构断裂失效的重要因素之一.目前疲劳裂纹扩展的有限元仿真商业软件有ANSYS、ABAQUS、FRANC3D、ZENCRACK等,这些软件为疲劳裂纹扩展过程的研究提供了有力支撑.本文对目前疲劳裂纹扩展的有限元仿真方法进行了综述.阐... 疲劳裂纹是引起工程结构断裂失效的重要因素之一.目前疲劳裂纹扩展的有限元仿真商业软件有ANSYS、ABAQUS、FRANC3D、ZENCRACK等,这些软件为疲劳裂纹扩展过程的研究提供了有力支撑.本文对目前疲劳裂纹扩展的有限元仿真方法进行了综述.阐明了疲劳裂纹的定义以及研究疲劳裂纹扩展行为的必要性;介绍了三种用于模拟疲劳裂纹扩展的有限元方法:扩展有限元法(XFEM)、内聚力模型(CZM)和虚拟裂纹闭合技术(VCCT);分别总结了三种方法的基本理论和核心思想,对三种方法的应用与发展进行了分类归纳;最后对三种有限元方法进行分析,指出每种方法各自的优势及目前存在的局限性,并对疲劳裂纹扩展有限元仿真技术的未来改进方向给出了建议. 展开更多
关键词 疲劳裂纹扩展 扩展有限元法 内聚力模型 虚拟裂纹闭合技术 数值模拟
下载PDF
考虑结合面特性影响的机床整机有限元静力学分析模型 被引量:1
17
作者 王豪 黄为彬 方兵 《机电工程》 CAS 北大核心 2024年第4期732-738,共7页
针对机床数字化设计中典型结合面建模精度误差较大的问题,提出了一种采用虚拟材料等效结合面静力学特性的方法,建立了考虑结合面特性影响的机床整机有限元静力学分析模型,并完成了相应的静刚度测试实验。首先,综合考虑了弹塑性变形机制... 针对机床数字化设计中典型结合面建模精度误差较大的问题,提出了一种采用虚拟材料等效结合面静力学特性的方法,建立了考虑结合面特性影响的机床整机有限元静力学分析模型,并完成了相应的静刚度测试实验。首先,综合考虑了弹塑性变形机制和摩擦力的影响,提出了一种新的结合面法向和切向刚度的分析模型;其次,根据不同类型结合面的特点,采用虚拟材料模拟结合面的刚度特性,建立了刚度特性与虚拟材料弹性模量和泊松比的关系,并将其应用于精密数控机床整机的静刚度分析;最后,开展了整机工艺系统的静刚度测试实验,得到了主轴末端X、Y、Z三个方向的刚度分别为26.60 N/μm、41.87 N/μm和40.17 N/μm,并将其与仿真数据进行了对比。研究结果表明:不考虑结合面影响的模型相对误差将近17%,而考虑结合面影响的模型相对误差在5%以内,验证了考虑结合面特性影响的机床整机有限元静力学分析模型的有效性;采用虚拟材料等效结合面静力学特性的方法可作为机床数字化设计的一种可行的方法。 展开更多
关键词 机床数字化设计 虚拟材料法 结合面静力学特性 静刚度测试 有限元静力学分析模型 弹塑性模型
下载PDF
一种三维Poisson-Nernst-Planck方程的虚单元计算
18
作者 丁聪 刘杨 +1 位作者 阳莺 沈瑞刚 《吉林大学学报(理学版)》 CAS 北大核心 2024年第2期293-301,共9页
利用虚单元方法在多面体网格上求解一种三维稳态Poisson-Nernst-Planck(PNP)方程,并给出PNP方程的虚单元离散形式,推导电势方程及离子浓度方程的刚度矩阵与荷载向量的矩阵表达式.数值实验结果表明,在3种不同的多面体网格下实现了PNP方... 利用虚单元方法在多面体网格上求解一种三维稳态Poisson-Nernst-Planck(PNP)方程,并给出PNP方程的虚单元离散形式,推导电势方程及离子浓度方程的刚度矩阵与荷载向量的矩阵表达式.数值实验结果表明,在3种不同的多面体网格下实现了PNP方程的虚单元计算,数值解在L^(2)和H^(1)范数下均达到最优阶. 展开更多
关键词 Poisson-Nernst-Planck方程 虚单元方法 多面体网格 三维
下载PDF
鸟粪形貌特性对220 kV复合绝缘子闪络影响的仿真分析
19
作者 蒋正阳 赵洪峰 《绝缘材料》 CAS 北大核心 2024年第7期135-142,共8页
通过COMSOL有限元仿真软件研究不同形貌特性的鸟粪对绝缘子闪络的影响。通过研究鸟粪的长度和黏度对闪络的影响以及鸟粪下落导致绝缘子闪络的过程,本文得出了不同黏度多段鸟粪构成的组合空气间隙击穿电压的计算方法。结果表明:鸟粪黏度... 通过COMSOL有限元仿真软件研究不同形貌特性的鸟粪对绝缘子闪络的影响。通过研究鸟粪的长度和黏度对闪络的影响以及鸟粪下落导致绝缘子闪络的过程,本文得出了不同黏度多段鸟粪构成的组合空气间隙击穿电压的计算方法。结果表明:鸟粪黏度越高,鸟粪的连续性越好,构成的空气间隙击穿电压越低,容易造成复合绝缘子闪络。因此若想提高防鸟罩对高黏度长鸟粪的防护能力,防鸟罩需具有减少鸟粪长度的能力。本研究在防鸟罩表面设计导流槽,将原本一段高黏度且长度较长的鸟粪通过导流槽分割成多段长度较短的鸟粪,通过减少鸟粪长度从而增加空气间隙长度,进而可以提高击穿电压,降低鸟粪闪络概率。 展开更多
关键词 复合绝缘子 鸟粪 有限元 虚拟介电常数法 黏度 闪络
下载PDF
基于虚拟材料法的金属膜片联轴器振动传递特性分析
20
作者 夏兆旺 张浩琪 +3 位作者 张帆 杨正奇 鞠福瑜 王一飞 《噪声与振动控制》 CSCD 北大核心 2024年第4期90-95,共6页
在对大型船舶金属联轴器进行振动性能试验时由于试验台架体积大、成本高,导致进行试验十分困难,因此研究高效率和高精度的仿真计算方法具有重要意义。传统精确的数值仿真网格多、效率低,为此采用虚拟材料法对船舶金属联轴器进行数值仿... 在对大型船舶金属联轴器进行振动性能试验时由于试验台架体积大、成本高,导致进行试验十分困难,因此研究高效率和高精度的仿真计算方法具有重要意义。传统精确的数值仿真网格多、效率低,为此采用虚拟材料法对船舶金属联轴器进行数值仿真并进行试验验证。首先通过计算和试验得到螺栓的虚拟材料层各参数,然后对大型金属联轴器的所有螺栓连接部位进行简化建模。其次通过该方法得到金属膜片联轴器的刚度特性、模态特性、阻抗特性和振动传递特性,并与传统建模方法的计算效率进行对比。最后搭建联轴器振动性能实验台架进行验证。研究结果表明:采用虚拟材料法的联轴器振动性能仿真效率提高73.9%;四组采用虚拟材料法的联轴器膜片组件刚度与实验测得的联轴器刚度的平均误差为2.61%,与带螺栓模型测得的刚度平均误差为1.15%。金属膜片联轴器前5阶模态频率仿真与试验的平均误差为9.91%,在10~2000 Hz频带,金属膜片联轴器轴向和径向阻抗的仿真与试验的误差分别为1.9和2.8 dB,金属联轴器轴向和径向的振级落差仿真与试验的误差分别为4.69和3.41 dB。试验与仿真结果误差较小,符合工程精度要求,该方法的计算效率和准确性得到验证。 展开更多
关键词 振动与波 金属膜片 联轴器 有限元分析 虚拟材料法 机械阻抗
下载PDF
上一页 1 2 17 下一页 到第
使用帮助 返回顶部