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三维近不可压缩弹性问题的罚函数有限元分析
Penalty Function Finite Element Analysis for Nearly Incompressible Elasticity Problems in Three Dimensions
 [PDF]

肖映雄,
International Journal of Mechanics Research (IJM) , 2014, DOI: 10.12677/IJM.2014.34005
Abstract:
对三维近不可压缩弹性问题,利用常规有限元进行求解时会出现体积闭锁现象,需要采用某些特殊的方法。罚函数协调有限元法具有程序实现简单、罚数易于确定以及不改变泛函驻值性质等特点,是克服体积闭锁现象的一种有效方法。本文,针对混合边界条件的三维近不可压缩问题,详细推导了罚函数有限元法的计算格式,分析该方法实施成功的条件,并通过数值实验验证了该方法对解决体积闭锁现象的有效性和鲁棒性。在三维有限元分析中,剖分网格的质量将对计算精度和求解效率产生很大影响,实际计算时若能采用各向同性网格,则对问题的分析将具有更好的收敛性。
The locking phenomenon will appear when the commonly used finite elements are applied to the solution of nearly incompressible problems in three dimensions. It is necessary to use some special methods. The penalty function conforming finite element method is an effective method to overcome this locking phenomenon since it is simple for the realization of the resulting program and easy to determine the penalty number and it also does not change the functional stationary value properties. In this paper, the computing format of penalty function finite element method is carefully derived, the conditions for success of the resulting method is analyzed and the effective-ness and robustness of this method are finally verified by some numerical experiments for nearly incompressible elasticity problems. The quality of the mesh used in three-dimensional finite ele-ment analysis has a great effect on the accuracy and computational efficiency. If the isotropic grids can be used in the practical calculations, the method will have better convergence.
甲基丙烯酸甲酯灌注法去制作金黄地鼠颊囊微血管铸型中的应用

动物学杂志 , 1994,
Abstract: 本文介绍了应有和甲基丙烯酸甲酯灌注.
牙种植学新进展

华西口腔医学杂志 , 2009,
Abstract: 随着牙种植学的快速发展,对牙种植体本身的设计、种植体骨界面的结合方式等方面不断有新理论出现。本文介绍了近年来提出的平台迁移骨保存技术、种植体—骨界面间的接触成骨和距离成骨理论,并对种植体设计和种植外科手术操作与这些理论之间的关系进行了讨论。
钢箱桩基坑围护结构研究
心培,
铁道工程学报 , 2012,
Abstract: ?研究目的:钻孔桩和地下连续墙是目前深基坑最常用的围护结构型式,但是这两种围护结构都存在工艺复杂、泥浆污染、水下混凝土质量不易保证、工程进度较慢和造价较高等问题。因此,笔者提出以打入预制的钢箱桩做基坑围护,本文从桩身刚度、强度、可实施性和社会、经济效益等方面进行研究,并论证其可行性。研究结论:(1)钢箱桩能满足基坑对围护结构刚度和强度的要求;(2)适用于沿海软土地区或沿江阶地;(3)用既有的机具设备即可打桩和拔桩;(4)不用钻孔或挖槽,没有泥浆污染;(5)简化设计和施工,加快工程进度;(6)钢箱桩可重复使用,节约资源,并且能降低工程造价;(7)推广应用具有较高的社会、经济效益。
FINITE ELEMENT NONLINEAR GALERKIN METHODS FOR PENALTY NAVIER-STOKES EQUATIONS
加罚N-S方程的有限元非线性Galerkin方法

李开泰,
计算数学 , 1995,
Abstract: In this paper we discuss the finite element nonlinear Galerkin methods of viscous incompressible Navier-Stoker (N-S) flow. The algorithm appears very ap-proriate for the long-time integration of these kinds of dissipated nonlinear time-dependent equations. We give the error estimates for a finite element nonlinear Galerkin method of the penalty N-S equation, in both, semidiscretization and full discretization.
STABILIZED FINITE ELEMENT METHODS OF A QUASI-NEWTONIAN FLOW OBEYING POWER LAW
服从幂律的拟牛顿流动稳定化有限元方法

,周天孝
计算数学 , 1997,
Abstract: In this paper, a Galerkin /least squares-type finite element method is proposed for a quasi-Newtonian flow, where the viscosity obeys the power law, The method is consistent and stable for P1/P1(PO) and Q1/Q1(QO) combination of discrete velocity and pressure spaces (without requiring the "inf-sup" stability condition).The existence, uniqueness and convergence of the discrete solution is proved.
FINITE ELEMENT METHOD FOR A THREE-FIELDS MODEL FOR QUASI-NEWTONIAN FLQW
拟牛顿流的一种三变量域模型的有限元方法的数值分析

,周天孝
计算数学 , 1997,
Abstract: This paper is concerned with the numerical analysis of viscous-elastic flow problems relating material creep deformation nature under high temperature. Early works in this area are those by Barret, Liu1], and Baranger and Najib 2]. These paper studied those model consisting only velocity and pressure as variables.Recently, in view of the special importance of the stress in material property,Baranger studied new finite element formula for quasi-Newtonian flow obeying power law, which consists stress, velocity and pressure as variables. Assume the Newtonian part is zero (see 3]), and one LBB condition is satisfied between the stress and velocity finite element spaces. Baranger has proven that the discrete formula has unique solution, and the error estimation is also deduced. Considering the restrictive condition given by 3] for finite element spaces, we can learn that it is difficult to use this method in practise.In this paper we constructs 4 new three field model, which also regards stress,velocity and pressure as variables, for above quasi-Newtonian flow problem, we also prove the existence and uniqueness of finite element solution, and deduce 'related error estimation, only by assuming a LBB condition hold between the velocity and pressure finite element spaces. Compared with that one in 3], the restrictive condition between velocity and stress finite element spaces is removed,thus we apparently relaxed the restrictive condition demanded to finite element space combination satisfying all our assumptions is proposed.
深基坑土钉加预应力锚杆支护结构设计参数的灵敏度分析
,
岩石工程学报 , 2014,
Abstract: 目前深基坑支护设计中,在土质和基坑周围环境允许的条件下,采用土钉加预应力锚杆复合土钉支护形式,与桩锚支护形式相比造价相对较低且施工速度快,所以在工程实践当中得到了广泛的应用,但土钉与预应力锚杆之间的作用机理相当复杂,在目前设计中往往靠经验设计,计算结果偏保守。基于圆弧滑动条分法,以内部整体稳定性安全系数作为目标函数并采用全局差分法建立灵敏度分析模型,研究设计参数与内部整体稳定系数及其灵敏度之间的关系,为深基坑工程中土钉加预应力锚杆复合土钉支护结构的优化设计提供重要的依据,对今后土钉加预应力锚杆复合土钉支护设计提供理论依据。
多功能并网逆变器及其在接入配电系统的微电网中的应用
刘宏达,
中国电机工程学报 , 2014, DOI: 10.13334/j.0258-8013.pcsee.2014.16.015
Abstract: 提出一种针对通过隔离变压器接入配电系统微电网的新型分布式电源多功能并网逆变器及其控制策略。综合运用瞬时无功功率理论和单位矢量的概念,根据分布式电源发电状态的不同,通过控制策略的设计,可以使多功能逆变器同时或分别实现由分布式电源向微电网注入功率的功能和在公在共连接点处进行谐波电流治理、负载无功补偿、负载三相不平衡和中性线电流补偿等并联型有源滤波器的功能。从而避免或减少对提高微电网电能质量装置的硬件投入,减少备总体积,使并网逆变器效益最大化。通过PSCAD仿真和实物搭建实验对该新型多功能并网逆变器及其控制策略进行验证,仿真和实验结果验证了相关设计的正确性和可行性。
高频噪声干扰器干扰主动声自导鱼雷仿真研究
,
兵工学报 , 2010,
Abstract: ?为优化声自导鱼雷对抗高频噪声干扰器弹道的设计,通过对高频噪声干扰器干扰机理及有效为优化声自导鱼雷对抗高频噪声干扰器弹道的设计,通过对高频噪声干扰器干扰机理及有效方位开角的研究分析,提出了高频噪声干扰器的干扰角度和干扰距离的计算方法及模型,并运用仿真实例,计算了某特定态势下的干扰区域。结果表明,通过合理设计声自导鱼雷的反水声对抗弹道,可以提高对抗的效果。该研究成果可为潜艇的水声对抗战术及鱼雷的反水声对抗弹道设计提供有益的参考。
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