Symmetric boundary using ANSYS modal analysis, make Happy New Year]

Continuation of last year's tradition, have been thinking in recent days to be something to welcome the New Year. Originally intended to train a network with a depth keras, recognizes "LZW I wish you all a Happy New Year" from a lot of pictures. But unfortunately, this year is changing too fast, it did not reach the level of practical application, so use it to do a simulation technology accumulated in the past, hope that next year in conjunction with a particular new technology to make a New Year blessing.

The origin of the idea

It focused on the simulation of multiphase flow with last year made a New Year blessing, structural analysis instead do it this year. Recall 10 years ago, in 2010, Intel in the old club, he participated in the first simulation project, and bi-directional mode blades FSI analysis. Though it was not quite understand, completed under the guidance of others, but clearly remember that feeling the effect of modal analysis of a shining, so we do a bar, when it was re-review of technology. Hope in the near future, simulation and manufacturing-related knowledge can help link up the twin digital technologies.

1. Modeling

DM using the workbench can not write, so starting a professional CAD tool to generate the geometric model with the word. Computer to upload the solidworks 2016, to use it to model it.

1. Because we wanted to use symmetry boundary conditions, so as to build a ring 1/8 base model. To facilitate processing of symmetry, both sides of the ring plus the two symmetrical wings as a boundary, but the wings can not contact the outer ring, or hard to deal with the contact surface.
2. When writing, selected center of the circle, using the character line structure arrangement. I had wanted to bold text, but seemingly bold when a software problem, there will be the phenomenon of self-stretching, they still use it in normal font.
3. In addition, the software uses unskilled, several operations did not find how to use, so do not a perfect model, DM put in for processing.

The final model is shown below:

Finally, exporting models to x_t format, ready for simulation .

2. symmetric boundary modal analysis

2.1 Processing geometric model

10 years ago, using a classic ANSYS, now workbench is so easy to use, so the simulation with ansys workbench19.0.

1. New project, drag a modal module;
2. Import selected geometry model geometry module;
3. 进行模型处理。为了让网格质量稍微好一些，所以把凸出来的字体和圆环分离，想分别划分网格，使用接触来处理。（后来发现好像不需要精度，索性就form new part了）。

2.2 网格划分并设置边界条件进行计算

1.首先建立圆柱坐标系：coordinate systems节点右键insert ‘coordinate system’,type选择‘Cylindrical’;
2. 指定对称边界：Model节点右键insert ‘symmetry’.
3. symmetry节点右键insert ‘cyclic region’。选择刚刚创建的圆柱坐标系，然后按照顺时针方向，选择low edge 和high edge.
4. 进行网格划分：网格 relevance center 选择’medium’, span angle center 选择’medium’。为了让边界节点map效果更好，把两个对称面设置个面尺寸，网格稍微密集些。
5. 建立约束：将圆环的内面固定，Modal节点insert ‘fixed support’,选择内圆环面；
6. 设置角速度：workbench的加速度不确定是哪一个，所以就用命令行来指定了。Modal节点，insert ‘commands’,输入

/solu

CSYS,0
ALLSEL,ALL
OMEGA,0,0,-300

  
ALLSEL,ALL  

对称边界如下所示：

网格模型如下：

2.3 求解

1. 设置Max modes to find =18，多算几个，最后选一个好看的
2. 求解

2.4查看结果

可以任意查看，我查看了各阶模态下的total deformation，然后选了旋转的那个作为视频结果。

如下图所示：

以上就是制作春节祝福的例子，没有追求精度和准确性。如果要是真的工程问题，处理起来应该会比这个多花很多时间。

If you are interested, we go to the resources that I uploaded, the file download is calculated modal analysis, as well as the calculation of multiphase flow file 2019: happy2020_cyclic.wbpz happy2019.wbpz