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本文先推导反平面复合材料切口尖端位移多应力场,然后用分区混合有限元法计算切口应力强度因子。 相似文献
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龙驭球 《应用数学和力学(英文版)》1987,(7)
The functional transformations of variational principles in elasticity are classified asthree patterns:Ⅰ relaxation pattern,Ⅱ augmented pattern and Ⅲ equivalent pattern.On the basis of pattern Ⅲ,the generalized variational principles with several arbitraryparameters are formulated and their functionals are defined They are:the generalizedprinciple of single variable u with several parameters,the generalized principle of twovariables u,σ with several parameters,the generalized principle of two variables u,εwith several parameters,and the generalized principle of three veriables u,ε.σ withseveral parameters.From these principles,a series of new forms of equivalent functionalscan be obtained.When the values of these parameters are properly chosen.a series of finiteelement models can be formulated.In this paper,the question of losing effectiveness for Lagrange multiplier method isalso discussed.In order to“recover”effectiveness for multiplier method,a modifiedmethod,namely,the variable substitutio 相似文献
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本文讨论圆底扁球壳在非对称载荷下的计算.给出了六种偏心集中载荷下的解,它们是:1.法向集中力,2.经线切向集中力,3.纬线切向集中力,4.切面内集中力偶.5.经线法面内集中力偶,6.纬线法面内集中力偶.此外,由偏心集中载荷的解还导出了按cosnθ分布的环形线载荷的解. 相似文献
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根据广义协调原理,首先利用Ferguson曲面构造出薄板弯曲单元,将中厚度板视为双向深梁,由Timoshenko理论拟合单元边界,利用Ferguson曲面的张量积性质,将薄板单元推广到中厚度板。数值结果表明此单元精度高,适应性强,且不出现剪切闭锁现象。 相似文献
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三维切口尖端应力应变场 总被引:4,自引:0,他引:4
本文利用双重幂级数展开法分析三维切口尖端应力应变奇异性,通过切口边界条件导出切口特征方程,进而求得不同切口内角下特征值序列解答,最后推得切口尖端应力应变场。 相似文献
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In this paper, the eigenequation of notch in Reissner plate is derived by the eigenfunction method. Eigenvalues of different notches with different angles are calculated by Muller iteration method.The expression of stress and strain at the tip of notch in Reissner plate is obtained. 相似文献
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A novel hybrid-stress finite element method is proposed for constructing simple 4-node quadrilateral plane elements, and the new element is denoted as HH4-3fl here. Firstly, the theoretical basis of the traditional hybrid-stress elements, i.e., the Hellinger-Reissner variational principle, is replaced by the Hamilton variational principle, in which the number of the stress variables is reduced from 3 to 2. Secondly, three stress parameters and corresponding trial functions are introduced into the system equations. Thirdly, the displacement fields of the conventional bilinear isoparametric element are employed in the new models. Finally, from the stationary condition, the stress parameters can be expressed in terms of the displacement parameters, and thus the new element stiffness matrices can be obtained. Since the required number of stress variables in the Hamilton variational principle is less than that in the Hellinger-Reissner variational principle, and no additional incompatible displacement modes are considered, the new hybrid-stress element is simpler than the traditional ones. Furthermore, in order to improve the accuracy of the stress solutions, two enhanced post-processing schemes are also proposed for element HH4-3β. Numerical examples show that the proposed model exhibits great improvements in both displacement and stress solutions, implying that the proposed technique is an effective way for developing simple finite element models with high performance. 相似文献