共查询到17条相似文献,搜索用时 125 毫秒
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线弹性模糊有限元方法是分析弹性介质体模糊特性对结构响应产生不确定性影响的有效方法。即使对弹性介质体而言,模糊有限元控制方程的求解时间问题也是困扰其推广应用的主要障碍。为获得可靠可行的模糊有限元控制方程的快速求解方法,在深入研究弹性介质体的模糊源特点基础上,提出当引起结构模糊特性的力学参数为单源模糊数时,可以利用单源模糊数的运算特点来求解模糊有限元的控制方程,进而利用合成运算求解结构的模糊位移和模糊应力的分布。推导了基于单源模糊数运算的弹性介质模糊应力和模糊位移的计算表达式。应用模糊有限元求解的区间解法和快速解法对算例进行比较分析,结果表明了快速解法的正确性。 相似文献
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含模糊参数弹性地基梁及桩的有限元分析 总被引:4,自引:1,他引:3
利用模糊有限元方法研究了文克尔地基上的梁和桩在确定性荷载作用下的反应,其中梁和桩身材料的物性参数及地基参数均模拟成模糊变量。在上述模糊变量为小变量的前提下,利用一种基于普通摄动法原理的模糊摄动展开方法求解模糊有限元平衡方程组得到结构反应量的模糊集。导出了用模糊摄动展开方法求解弹性地基上梁和桩的计算公式,并研究了结构中各模糊参变量对结构反应量模糊集的影响。经与数值模拟的结果比较后表明,方法在精度和实用性方面可较好的满足要求。 相似文献
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The vertex solution theorem and its coupled framework for static analysis of structures with interval parameters 下载免费PDF全文
Zhiping Qiu Zheng Lv 《International journal for numerical methods in engineering》2017,112(7):711-736
This work gives new statement of the vertex solution theorem for exact bounds of the solution to linear interval equations and its novel proof by virtue of the convex set theory. The core idea of the theorem is to transform linear interval equations into a series of equivalent deterministic linear equations. Then, the important theorem is extended to find the upper and lower bounds of static displacements of structures with interval parameters. Following discussions about the computational efforts, a coupled framework based on vertex method (VM) is established, which allows us to solve many large‐scale engineering problems with uncertainties using deterministic finite element software. Compared with the previous works, the contribution of this work is not only to obtain the exact bounds of static displacements but also lay the foundation for development of an easy‐to‐use interval finite element software. Numerical examples demonstrate the good accuracy of VM. Meanwhile, the implementation of VM and availability of the coupled framework are demonstrated by engineering example. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
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采用随机收敛的非正交的多项式展式表示未知的随机屈曲特征值和屈曲模态,利用摄动技巧,建立了随机结构弹性屈曲的递推求解方法。算例表明,和基于泰勒展开的摄动随机有限元方法相比,方法的结果能在较宽的随机涨落范围内更好地逼近蒙特卡洛模拟结果,即使只采用前四阶非正交多项式展式,逼近的结果仍然较好。 相似文献
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N. S. Khot V. B. Venkayya L. Berke 《International journal for numerical methods in engineering》1976,10(5):1097-1114
This paper presents an optimization method based on optimality criterion for minimum weight of structures with stability requirements. A recurrence relation is derived and the method is explained in the context of the displacement method of finite element analysis. The incipient buckling of the structure is determined by a linear eigenvalue solution. The method is programmed for trusses and frames. Illustrative problems are given to show the applicability of the method of design of structures with a large number of design variables. 相似文献
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P. Daly 《International journal for numerical methods in engineering》1973,6(2):169-178
This paper deals with the extension of the finite element method as applied to the solution of the Laplace or wave equation to cylindrical co-ordinate systems. The base matrices required for solving problems governed by these equations are derived for circular polar, elliptic cylinder and parabolic cylinder co-ordinates. The matrices allow problems whose boundaries are described as co-ordinate surfaces in cylinder co-ordinates to be attacked directly by the finite element method. The subject is discussed from the point of view of one interested in electromagnetic wave propagation in uniform waveguide structures. 相似文献
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Ke Liang Mostafa Abdalla Zafer Gürdal 《International journal for numerical methods in engineering》2013,96(12):763-786
A new approach termed the Koiter‐Newton is presented for the numerical solution of a class of elastic nonlinear structural response problems. It is a combination of a reduction method inspired by Koiter's post‐buckling analysis and Newton arc‐length method so that it is accurate over the entire equilibrium path and also computationally efficient in the presence of buckling. Finite element implementation based on element independent co‐rotational formulation is used. Various numerical examples of buckling sensitive structures are presented to evaluate the performance of the method. The examples demonstrate that the method is robust and completely automatic and that it outperforms traditional path‐following techniques. This improved efficiency will open the door for the direct use of detailed nonlinear finite element models in the design optimization of next generation flight and launch vehicles. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献