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广义协调平板型矩形壳元 总被引:8,自引:0,他引:8
本文根据修正势能原理通过广义协调方法提出了一种列式简单的平板型矩形壳元GCR24。它在四个角点处各有六个自由度,总共二十四个自由度。作为一种极限协调元,单元的收敛性得到保证,并且不发生薄膜闭锁现象。通过标准问题的数值检验,表明本文提出的平板型矩形薄壳元是性能可靠,计算精度优质单元。 相似文献
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本文用Hankel变换的方法,将解表成级数的形式,求得了一般扁壳齐次方程的解。由齐次方程的一般解,叠加无孔无限壳的特解,可得扁壳圆孔附近应力集中问题的解。 相似文献
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本文基于修正的势能泛函,引入适当的广义协调条件,导出了一种具有12个自由度的广义协调板弯曲扇形位移单元GC—S12,这种单元自由度少,列式简单,精度高。 相似文献
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本文根据广义协调元的基本思路,引入常弯矩下的广义协调条件,导出具有九个自由度的薄板三角形第Ⅰ类广义协调元GcI-T9。其推导方法同通常的非协调元一样简单,可沿用常规方法加以实施。由于满足常弯矩下的广义协调条件,本单元可以保证通过分片检验。算例表明GCI-T9能以少的自由度得到好的计算精度。 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
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分区混合有限元法求混合型应力强度因子 总被引:2,自引:0,他引:2
本文在早先工作[1],[2]的基础上,进一步用分区混合有限元法求解平面断裂问题的应力强度因子,作了两点改进:1.余能区单元采用多个应力参数;2.求解的问题可包括混合型问题。文中给出了几个典型算例,显示出本法的一些优点。 相似文献
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构造几何不敏感四边形膜元的广义协调方法 总被引:8,自引:0,他引:8
许多有限元模型在规则网格下具有很高的精度,但当网格畸变程度增大时,其计算精度也随之迅速下降.如何构造出对网格畸变不敏感的单元,长期以来是人们十分关注的课题.本文应用作者早期提出的广义协调方法,构造出具有平面内旋转自由度的任意四边形膜元.该单元不仅列式简洁,而且具有对网格畸变极不敏感的优异性能,为构造对网格畸变不敏感的优质单元提供了一个通用方法 相似文献