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一种三维体罚平衡应力杂交元 总被引:1,自引:0,他引:1
主要研究三维体罚平衡杂交元理论并建立相应的单元模型,采用罚平衡方法可以在不增中自由度的前提下,有效地扼制寄生应力,从而大幅度提高畸变网格下的计算精度,所给算例对8节点空间六面体单元(DM8)、优化杂交元和该文得出的单元进行了比较,证明了这一点,文中还尝试将该文 于方板和不可压缩问题的计算,得出了令人满意的结果。 相似文献
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利用有限元特征分析法研究了平面各向异性材料裂纹端部的奇性应力指数以及应力场和位移场的角分布函数,以此构造了一个新的裂纹尖端单元。文中利用该单元建立了研究裂纹尖端奇性场的杂交应力模型,并结合Hellinger-Reissner变分原理导出应力杂交元方程,建立了求解平面各向异性材料裂纹尖端问题的杂交元计算模型。与四节点单元相结合,由此提出了一种新的求解应力强度因子的杂交元法。最后给出了在平面应力和平面应变下求解裂纹尖端奇性场的算例。算例表明,本文所述方法不仅精度高,而且适应性强。 相似文献
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根据Hellinger-Reissner原理,建立了进一步改进的具有一个无外力圆柱表面三维杂交应力元.元内假定应力场满足以柱坐标表示的平衡方程,及圆柱面上的无外力边界条件.当退化为二维时,也满足协调方程.数值算例表明,当分析带圆弧的槽孔板、块时,在稀疏的有限元网格下,这类单元即可提供较以前各类特殊元、一般假定位移元及一般假定应力元远为准确的三维及二维应力分布. 相似文献
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杂交应力通用壳元的模式优化 总被引:1,自引:1,他引:1
文章把杂交元的优化设计原理用于厚薄壳问题,构造了正交曲线坐标系中的Mindlin型四节点二十自由度壳元。该元通用于各种厚度、任意形状的深壳和扁壳,构造简单,精度较高且没有自锁现象。 相似文献
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Based on a modified Hellinger/Reissner variational principle which includes the equivalent stress, equivalent plastic strain and non-conforming displacement increments as independent variables, a quadrilateral isoparametric hybrid stress element for the analysis of elastoplastic problem is proposed. By this formulation, the yield criterion and flow rule are satisfied in an average sense and greater accuracy can be obtained by using non-conforming displacement. A numerical example is presented to show that the present model has high accuracy and computational effectiveness.This project is supported by the Natural Science Foundation of the State Education Commission. 相似文献
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THE STRESS SUBSPACE OF HYBRID STRESS ELEMENT AND THE DIAGONALIZATION METHOD FOR FLEXIBILITY MATRIX H
IntroductionInfiniteelementanalysis,thedisplacementelementsareverypopularbecauseoftheireasyconstruction .However,itisverydifficulttoassumethecontinuousdisplacementfieldforsatisfactoryshellelementsthatisfreefromshearlocking .In 1 964 ,thehybridstresselementw… 相似文献
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详细讨论了光测粘弹性介质中光学及力学参数测试的理论及方法。首次提出用边界元与光粘弹性法相结合求解粘弹性体中应力分析的新方法,并推导出了相应的公式.以粘弹性简支梁为实例验证了我们提出的方法. 相似文献
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本文用云纹干涉法测取双材料高梁受集中载荷时沿x,y轴的位移场u,v.以其作为界面局部微区的边界条件,用有限元计算此微区内界面上的应力分量.与光弹性及全梁有限元法比较,发现局部杂交法的精度最高. 相似文献
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Chen Wang Xiwu Xu 《Acta Mechanica Solida Sinica》2014,27(3):315-330
A hybrid finite element for exponentially varying Fhnctionally Graded Material (FGM) is established based on a derived stress field for an intact plate. Elements with both single layer and two layers of gradient are presented. The general stress field is obtained through an asymptotic analysis coupled with Westergaard's stress function approach. With the aid of boundary collocation technique, convergence of the derived stress field is verified. Effectiveness and efficiency of the element is investigated through calculation and comparison. Based on that element, stress field of FGM plate under different loading cases is studied briefly. 相似文献
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