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发表于 2003-6-9 21:17:01
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来自 陕西西安
回复: comma blueangle help!!! help!!! help!!!!
xyjwqe666 wrote:
1. 在nastran中,零件的分析和求解是简单的,在对于装配件有很多的问题(指模型),主要是零部件的连接部,节点和单元不能重合,即使重合又不太符合实际,实际情况中,零件不可能都是刚性连接的,nastran中是否有合适的单元或方法来模拟它?我是在patran中建模的,先谢了!!
2. 在分析约束情况时,六个自由度应该按照那个coord?element coord 还是 default coord??? 试以联接件螺钉分析分析,谢谢。(划分单元时螺钉也有单元的)
3.在patran中,划分单元时是按照物理模型来划分的,(几何模型也可,不过误差大),尤其常用的是梁单元,但梁单元的几何体是一条从中面提取的curve,这样没法保证与其他部分的连接,比如在结构中常用的法兰,可以用一环形梁来代替(一条圆曲线),但由于梁提取的是中面线,与其他部分就有了距离,节点无法合并,这是不是与第一个问题一样?肯盼赐教,谢谢!
4.接触分析是什么啊?
我的邮箱:xyj@opt.ac.cn
怎没人看我的帖子阿!!
:(:(:(:(:(:(
谢谢各位!我的问题我懂了!下面是摘自<nastran user's guide>的一段话!
Multiple Constraint:
In MSC/NASTRAN ,the term Multiple-Point Constraint is used to describe an imposed linear relationship between two or more degrees of freedom that.......
...................
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Multiple-point constraint have many important practical applications and can be used to:
Defined the relative motion between two grid points as a degree of freedom;
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Join dissimilar elements,for example ,to join element with rotational degrees of freedom to element that have only trnslational degrees of freedom (e.g.,to join shell element to solid element)
.......................
Join element with noncoincident grid points ,for example,to change mesh size within a structure.
大家看看是不是解决了,希望多多发表意见!! |
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