MITC单元公式推导过程
本帖最后由 dongsheng01 于 2011-7-28 10:23 编辑本人在学习MITC单元,这种单元可以有效的避免剪切闭锁现象,现在我要改形函数,因此需要公式推导的过程,书上给出了推导过程,但是我不懂张量,希望高手给予解答,书上的公式如下 请问有人知道公式5.103是如何推导出来的吗?:) 2# dongsheng01 If you understand example 5.30, you should be able to understand equation 5-103. I see nothing tricky here. 本人在学习MITC单元,这种单元可以有效的避免剪切闭锁现象,现在我要改形函数,因此需要公式推导的过程,书上给出了推导过程,但是我不懂张量,希望高手给予解答,书上的公式如下
dongsheng01 发表于 2011-7-28 10:20 http://forum.simwe.com/images/common/back.gif
lz还是去找找龙驭球课题组的基于解析试函数的中厚板单元的论文,推导比MITC单元更简单直白,计算精度、收敛性要比之稍好一些 Can someone find the paper and upload it? Thanks in advance.
4# pasuka 5# tonnyw
I think LZ should do that. Can someone find the paper and upload it? Thanks in advance.
4# pasuka
tonnyw 发表于 2011-7-28 13:36 http://forum.simwe.com/images/common/back.gif
都是根据胡海昌中厚板方程出发来推导的 7# pasuka
在吗?加我qq287071165 大家一起讨论讨论:) 7# pasuka
在吗?加我qq287071165 大家一起讨论讨论:)
dongsheng01 发表于 2011-7-28 15:28 http://forum.simwe.com/images/common/back.gif
有问题就在这里问吧,这里达人多 7# pasuka
我现在要改形函数N不知道你说的那种单元时否适合改形函数,谢谢:) 10# dongsheng01
我要做的是薄板,你发的这个文献是厚板单元,不知道有没有薄板,可以闭合剪切闭锁现象的 本帖最后由 pasuka 于 2011-7-28 16:00 编辑
10# dongsheng01
我要做的是薄板,你发的这个文献是厚板单元,不知道有没有薄板,可以闭合剪切闭锁现象的
dongsheng01 发表于 2011-7-28 15:46 http://forum.simwe.com/images/common/back.gif
薄板单元一般不考虑剪切效应,所以不会有剪切锁死的问题 12# pasuka
嗯,我现在要做的是裂纹的扩展问题,需要考虑了剪切,而且是薄板 12# pasuka
嗯,我现在要做的是裂纹的扩展问题,需要考虑了剪切,而且是薄板
dongsheng01 发表于 2011-7-28 16:01 http://forum.simwe.com/images/common/back.gif
裂纹的话,最好还是用无网格、边界元等方法,或者用XFEM扩展有限元 14# pasuka [/
我用的是xfem,但是要做板单元的,所以需要找到一种方便的板单元 14# pasuka [/
我用的是xfem,但是要做板单元的,所以需要找到一种方便的板单元
dongsheng01 发表于 2011-7-28 17:44 http://forum.simwe.com/images/common/back.gif
薄板单元,最方便的话,还是ACM单元,推导简单、收敛性和精度都有保证 16# pasuka 谢谢了:) 17# dongsheng01 请问一下,你看的这本书名字叫啥? 另外龙驭球老师采用的是广义协调元,根据他们的实验结果要比非协调元好一点,但是单元形式要复杂很多。
lz还是去找找龙驭球课题组的基于解析试函数的中厚板单元的论文,推导比MITC单元更简单直白,计算精度、收敛性要比之稍好一些
pasuka 发表于 2011-7-28 12:46 http://forum.simwe.com/images/common/back.gif
No hurry to reach such conclusion.
1. First, there is no comparison in the paper that shows us the generalized conforming plate element has performance than MITC plate element.
2. MITC plate element is the special case of MITC shell element. This is not the case for generalized conforming elements.
3. The convergence test is too rough. We cannot be sure that the generalized element is locking free in the case of twisted element. I am surprised that the paper does not show the convergence curve based on H1 norm or energy norm since exact solution is known. Pointwise comparison can send wrongful information.
4. I suggest dongsheng01 focus on MITC plate element first to see how the results look like. The reliability of MITC plate element is well tested since it has been used in Adina for quite long time.
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