共查询到19条相似文献,搜索用时 62 毫秒
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平面八节点四边形理性元 总被引:2,自引:0,他引:2
推导平面八节点四边形理性有限元列式,采用具有直到四次多项式的平面问题的微分方程的解作为插值函数,算例结果表明平面八节点四边形理性有限元的有效性. 相似文献
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空间理性八节点块体元 总被引:1,自引:0,他引:1
推导出空间八节点块体理性有限元列式,采用具有直到三次多项式的空间问题的微分方程的解作为插值的近似函数,数例结果表明空间理性八节点块体元的有效性。 相似文献
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有限元收敛性与分片试验条件 总被引:3,自引:1,他引:3
本文就平面弹性问题给出了分片试验的条件,并给出了其明确的物理意义。条件用公式表达,并证明了就是工程式分片试验的充分必要条件,同时还证明了这些公式也是单元收敛的充分必要条件,本文的方法可以推广到有限元分析的其它问题去。 相似文献
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平面理性四节点及五节点四边形有限元 总被引:5,自引:2,他引:5
推导了平面四点及五点理性元公式,具有完全二次解的插值近似,完全通过分片试验,不发生零能模式,不发生剪切自锁。数例表明本文理性元的优越性。 相似文献
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精化直接刚度法的不协调位移模式与收敛性分析 总被引:6,自引:0,他引:6
基于精化直接刚度法的不协调位移模式及有限元收敛理论中的IPT条件,建立了C ̄0类可分离位移型精化元的收敛性充分条件——强IPT条件。进一步推出一族平面及空间C ̄0类精化元并验证了其收敛性。 相似文献
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精化不协调平面八节点元 总被引:2,自引:0,他引:2
用直角坐标表示的多项式直接插值,建立了满足的收敛要求的不协调平面八节点单元,其列式比等参协调元法简单,直接,单元精度高且可推出刚度阵显式。 相似文献
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导出了轴对称非协调元分片检验中检验函数的形式,其位移函数是一种不完全的线性函数。从而给出了轴对称非协调调元分析检验更准确,完全的描述。 相似文献
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This investigation is intended to develop a computer procedure for the integration of NURBS geometry and the rational absolute nodal coordinate formulation (RANCF) finite element analysis. A linear transformation is given that can be used to convert the NURBS curve to RANCF cable element mesh retaining the same geometry and the same degree of continuity, including the discussion of continuity control and mesh refinement. The green strain tensor is used to establish the nonlinear dynamic equations with numerical examples to demonstrate the use of the procedure in the dynamic analysis of flexible bodies. 相似文献
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A p-type finite element scheme is introduced for the three-dimensional shallow water equations with a harmonic expansion in time. The wave continuity equation formulation is used which decouples the problem into a Helmholtz equation for surface elevation and a momentum equation for horizontal velocity. An exploration of the applicability of p methods to this form of the shallow water problem is presented, with a consideration of the problem of continuity errors. The convergence rates and relative computational efficiency between h- and p- type methods are compared with the use of three test cases representing various degrees of difficulty. A channel test case establishes convergence rates, a continental shelf test case examines a problem with accuracy difficulties at the shelf break, and a field-scale test case examines problems with highly irregular grids. For the irregular grids, adaptive h combined with uniform p refinement was necessary to retain high convergence rates. © 1997 John Wiley & Sons, Ltd. 相似文献
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对层合板引入小应变中转动几何非线性假设,位移模式考虑了横向剪切应力及其连续性,有采用罚单元的方式构造了简单,协调的八节点等参单元,并应用于层合板的应力分析,取得了很好的数值结果。 相似文献
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板壳有限变形精确理论及有限元列式 总被引:1,自引:0,他引:1
以位移型退化壳理论为基础,提出了板壳模型的有限变形精确理论.该理论引入转动伪矢量概念,充分发挥刚性线段的运动学模型和有限转动矩阵的作用,精确表达非线性位移-应变关系,抛弃以往的小位移、小应变、小转动增量乃至小加载步长等各种简化假设,并严格遵循能量共轭关系建立有限元平衡方程,能够可靠和有效地用于板壳结构的大位移、大转动分析.算例表明,该文列式在弹性范围内具明显的平方收敛效率,并且计算结果与加载步长无关.由于不受小加载步长、小转动增量等的限制,实现了板壳几何非线性问题的大步长加载 . 相似文献
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In the structural design of civil aircraft the critical loads are often those encountered in a gust or atmospheric turbulence. The traditional ‘indicial’ solution is restricted to a simple plate. In this paper a finite element formulation is proposed for an aerofoil or arbitrary shape entering a uniform sharp-edged or sinusoidal gust. The thin rotational gust front and wake in an irrotational flow field are successfully modelled by a novel superposition technique. The finite element solutions are compared with the Kussner function and results by other numerical methods. The agreement is good. 相似文献