冶金工程中映射网格划分技巧

冶金工程中映射网格划分技巧 Mesh mapping techniques in metallurgical engineering 1.对于面来说，使用映射网格划分需要满足以下几个几何拓扑结构的要求条件： For surface, using a mapping grid needs to meet the requirements of the following geometrical topology conditions:

*面必须有三条或四边线的边界组成

*The boundary of the surface must have three or four line *一般来说，对边的应划分成相等的个数 *In general, the edge should be divided into equal number

映射网格划分一直是大家关心的问题，现把自己使用ansys的一些经验及编程的真实体会奉献给大家，希望能达到授之以渔的效果。 Mesh mapping has been a problem, everybody CARES now to some real programming experience and experience of using ansys give you, hope to be able to achieve the result of teach to fish. ansys执行映射网格划分的条件是：对于面，必须是三角形或四边形，对于体，必须是四面体、五面体或六面体，这是众所周知的，但往往忽略了另一个条件：划分数的匹配问题，对于四边形而言必须满足对边划分数相等的条件，对于三角形，在后面作专门介绍。其实ansys不仅可以对三角形和四边形执行映射网格划分，对任意多边形原则上（划分数匹配）都可以执行影射网格划分，这些方法包括：面的切割、线的合并等，这些方法也可以用在体的映射网格划分上。 Ansys executive mapped meshing condition is: the surface, must be a triangular or quadrilateral, for the body, must be a tetrahedron, pentahedron or hexahedron, it is well known, but often overlooked another condition: dividing the number of matching problem, must satisfy the edge for quadrilateral partition number equal conditions, for triangle, introduce specifically in the rear. Actually ansys can not only the triangle and quadrilateral mesh mapping, execution of arbitrary polygons in principle (partition number matching) can perform mapping grid, these methods include: the cutting, wire, etc, these methods can also be used in the mapping of the mesh. 我今天要介绍的是另一种方法（可能在论坛上已经有类似的介绍，但我还没有看到，如果有，就算重温吧）也即amap命令（基于面的角点的映射网格划分）的使用，它需要指定要划分的面的编号，以及以任意顺序指定该面上的任意4个角点（注意：任意四个角点是有前提的，即划分数的匹配，为了不再罗嗦，以后不在重复强调这个问题）。 I want to introduce today is another method (can have similar introduction on the BBS, but I have not seen, if you have, even if to revisit?) which is amap order (based on the corner of the map grid), the use of it needs to be specified to divide the number, and in any order specified on the face of any four corners (note: any four corner point is a premise, namely, dividing the number of matching, in order to no longer bothersome, later not repeated emphasis on this problem). 看一个简单的例子（如图1，尺寸见坐标），这个图形由3个面组成其中A2和A3满足映射网格划分的条件，A1看起来是个矩形但其实由5条边组成，要实现A1的影射网格划分，你可以用工作平面将其沿着L6切开，但这样就会多出一条线，某些情况是不希望有多余元素生成的，比如把图1看成是一块楼板，线就是梁，如果切割后就多出了一条线，对以后定义梁造成不便。这个问题不能用lcomb命令将线2和线4合并（自己可以试一下），另一个方法就是用amap,1,4,7,8,6。理论上amap命令可以用于任何多边形，但往往理论是实际是有差距的，还是刚才那个例子，如果你将线的划分尺寸定义为1（lesize,all,1），则线10的划分数为1，线2和线4各为1,然后你再用同样的命令amap,1,4,7,8,6，看看有什么结果——划分数不匹配，不能进行映射网格划分。相关命令流如下： Look at a simple example (see coordinates) as shown in figure 1, the size, the graphic is composed of three level of A2 and A3, to meet the mapping grid conditions, A1 but it looks like a rectangle is composed of five edge, to achieve A1 alluding to the grid partition, you can use the work plane to be cut along the L6, but it would be more than a line, in some cases is don't want there to be redundant elements, such as the figure 1 as a floor, line is the beam, if after cutting out a line, to define beam inconvenience in the future. This problem can't use lcomb command incorporates the line 2 and line 4 (you can try), another method is to use amap, 1,4,7,8,6. Amap command can be used for any polygon in theory, but theory is actually often have a gap, or just the example, if you will wire the partition size is defined as 1 (lesize, all, 1), is the division of line 10 number is 1, line 2 and line 4 to 1, then you use the same command again amap, 1,4,7,8,6, see what's the result - the partition number do not match, can't be mapped meshing. Relevant command flow is as follows:

/PREP7 k k,,1 kgen,3,1,2,1,,1 a,1,2,4,3 a,3,4,6,5 et,1,42 wprota,,,90 wpoffs,,,0.5 asbw,1,,dele amap,2,3,4,5,6 aclear,all lesize,all,1 amap,2,3,4,5,6 以上命令流所建模型的编号跟图1有些不同。从这个简单的例子大家应该能够体会到划分数匹配的重要性了，实际工程中的图形远比这个复杂得多，要想完全满足划分数匹配的条件是很不容易的，甚至可以说几乎不可能，除非全部分割成4边或3边形，但这样会产生很多小面影响网格划分的质量，这在建筑结构中是很常见的，我做过几个实际工程，深有体会。因此amap命令的使用也有局限性，在实际工程中可以综合使用多种方法以达到最优化。 Look at a simple example (see coordinates) as shown in figure 1, the size, the graphic is composed of three level of A2 and A3, to meet the mapping grid conditions, A1 but it looks like a rectangle is composed of five edge, to achieve A1 alluding to the grid partition, you can use the work plane to be cut along the L6, but it would be more than a line, in some cases is don't want there to be redundant elements, such as the figure 1 as a floor, line is the beam, if after cutting out a line, to define beam inconvenience in the future. This problem can't use lcomb command to the serial number of the model with the above command flow figure 1 a little different. From this simple example, you should be able to realized the importance of partition number matching, in actual engineering graphics is far more complicated than this, if you want to completely satisfy the partition number that matches the condition is very not easy, and could even say that almost impossible, unless all split into 4 or 3 while form, but this will produce a lot of small surface affects the quality of the mesh, it is very common in building structures, I have done some actual projects, have experience greatly. Therefore amap order use also has limitations, can be integrated in the practical engineering using a variety of methods to achieve optimization.