什么是“真实”三维空间中和元素自身的“自然“坐标空间

SANYAN68

Figure 2.5  Avoid Midside-to-Corner Node Connections Between Elements

For elements having midside nodes, it is generally preferred that each such node be located at the straight-line position halfway between the corresponding corner nodes. There are, however, situations where other locations may be more desirable:

Nodes following curved geometric boundaries will usually produce more accurate analysis results - and all ANSYS meshers place them there by default.

Even internal edges in some meshes may have to curve to prevent elements from becoming inverted or otherwise overly distorted. ANSYS meshers sometimes produce this type of curvature.

It is possible to mimic a crack-tip singularity with "quarter point" elements, with midside nodes deliberately placed off-center. You can produce this type of specialized area mesh in ANSYS by using the KSCON command (Main Menu> Preprocessor> Meshing> Size Cntrls> Concentrat KPs> Create).

Midside node positions are checked by the element shape test described below. (For information about controlling element shape checking, see Generating the Mesh of this manual.)

All solid and shell elements except 3-node triangles and 4-node tetrahedra are tested for uniformity of the mapping between "real" 3-D space and the element's own "natural" coordinate space. A large Jacobian ratio indicates excessive element distortion, which may or may not be caused by poorly located midside nodes. For details about Jacobian ratio tests, refer to the section on element shape testing in the Theory Reference for the Mechanical APDL and Mechanical Applications.

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红字处的翻译是否正确....

除了3节点三角形和4节点四面体之外都经过测试
所有固体和壳元素之间一致性对应连结
“真实”三维空间中和元素自身的“自然“坐标空间。

什么是“真实”三维空间中和元素自身的“自然“坐标空间。

Chelsea

除了3节点三角形单元和4节点四面体单元外，所有实体单元或者壳单元从三维空间坐标系到单元坐标系映射的一致性都需要经过测试

SANYAN68

Chelsea 发表于 2011-3-11 23:39

                               
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除了3节点三角形单元和4节点四面体单元外，所有实体单元或者壳单元从三维空间坐标系到单元坐标系映射的一致 ...

请教版主...
"real" "natural"
为何没有提到呢? 映射的一致性都需要经过测试.....是程式本身会自动测试吗?

Rainyboy

回复 3 # SANYAN68 的帖子

real  space可翻译为 “物理空间”，即你自己建模的时候设置的坐标系
natural coorniate 可翻译为“单元坐标系”，即为了得到统一的单元刚度矩阵而设定的坐标系，是一个中间过程，当然，在这个坐标系中生成的单元刚度矩阵需要经过坐标转换，转换到real coorniate中，才是最终组集到总刚度矩阵中的单元刚度矩阵，这个过程中，如果变换矩阵J，即后文所述的jacobian矩阵奇异（比如不合理的单元扭曲），就会导致这个由real到natural的过程不是一一对应的。因此，这里说的"test"应该就是单元形状检查（element shape test），由程序自动完成。

Chelsea

楼主有点太过注重字译，而忽略了意译
说明书关键在与意思准确
至于具体到某个具体的词语有的时候没必要深究
很多时候是一些专有名词或者表达习惯的问题