# Problem in generation of 2d model

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• Last Post 15 January 2019
• Topic Is Solved
rrathishubham posted this 12 January 2019

Hello everyone, I'm new to ANSYS so please dont mind if this is a really silly one. I'm trying to generate a model of cooling tower using axisymmetric but the problem is that i dont know how to place it at a position to get a proper radius and revolve it around y axis. I have attached a screenshot of cooling tower in 3d but i want the same in 2d. Please help.

Attached Files

rrathishubham posted this 15 January 2019

Okay sir... And yes, the slice from 4 curves is radial slice. I'll try to do it without reinforcement.

peteroznewman posted this 15 January 2019

A 2D axisymmetric model is used to calculate and visualize the stress and strain on a 2D radial slice of a 3D rotationally symmetric object. The surface you created from the four curves is that radial slice. The surface is what you mesh. You also have to support and load the structure. I suggest a fixed support for the bottom edge and Standard Earth Gravity in the -Y direction. By default, all models begin with Structural Steel. If you want to use a different material, you have to create that in Engineering Data, and then you have to assign that to the surface in Mechanical. Then you can solve and look at results. There is a way to display the results from the surface by revolving the results around the axis to display the results in 3D.

Reinforcement is done in 3D. It doesn't make sense in 2D except for a hoop that goes around the axis. You can't have any axial reinforcements that are only every 20 degrees because that is not axisymmetric.

I recommend you get results from a 2D axisymmetric model of an unreinforced material before you venture into 3D models.

Once you have 2D results, you can mark this discussion with Is Solution and open a New Discussion for questions on reinforcements in 3D models.

rrathishubham posted this 15 January 2019

Sir, I have revolved the geometry in mechanical tab. Also I have meshed it. Could just tell me about the reinforcement?

rrathishubham posted this 15 January 2019

Also, can i put reinforcement in 2D model? Or do I need to model it in 3D? If I can put the reinforcement in 2D model, then how can I put?

rrathishubham posted this 15 January 2019

Sir, I made the geometry using 4 groups and later using "Surface from Edges", I created surface. Is it correct? And once I take the geometry into mechanical tab, I cant see any option to revolve the geometry.

peteroznewman posted this 14 January 2019

You can have four groups in a single text file.

Group 1 can be the inner curve from the bottom to the top.

Group 2 can be from the inner top to the outer top (two points).

Group 3 can be the outer curve from top to bottom (reverse sort the height).

Group 4 can be from the outer bottom to the inner bottom (two points).

I think you will be able to select these four curves to make a surface.

rrathishubham posted this 14 January 2019

Sir, I was able to import the file and it created the curve as I wanted but could you please tell me that how do I create closed geometry? I even read the link you provided but I didn't understand that what should be the format for closed geometry and in the last row where shall I put 1 and 0 to close geometry.

rrathishubham posted this 14 January 2019

Thankyou so much for your reply. I'll revert back once i create the geometry. Once again thankyou sir, thanks a lot.

peteroznewman posted this 14 January 2019

Here is the plan. Take the spreadsheet and make two tabs, one for the inner surface, one for the outer surface. On the tab for the inner surface, delete the Thickness column. Cut the Radius column and paste it in front of the Height column. Now the first column is the X coordinate, the second column is the Y coordinate. Fill the third column with 0.0 for the Z coordinate.

On the second tab, in the fourth column, add the radius to the thickness to make the Y coordinate of the outer surface. Cut that column and Paste Special (Values) in front of column A to be the X coordinate. The height is the Y coordinate and insert a column of 0.0 for the Z coordinate. Delete the other rows.

Next you have to format those two tabs into the 3D Curve data format that DesignModeler requires.

Once you have a text file with the data in the correct format, you start a new Workbench file. RMB on the Geometry cell and get the Properties.  You must set the Analysis Type to 2D before you open DesignModeler.

In DesignModeler, Concept, 3D Curve. Definition > From Coordinates File. Then pick the inner surface file.  Repeat for the outer surface file.

Finally, make a sketch that uses those two 3D curves and two lines to close off the cross-sectional surface that is the geometry that can be meshed to perform an axisymmetric model.

Alternatively, you could put the inner and outer coordinates in one file and define a closed 3D line and you wouldn't have to sketch the two lines.

rrathishubham posted this 14 January 2019

I'm using version 18.1

peteroznewman posted this 14 January 2019

What version of ANSYS are you using:  18.2  19.2  other?

rrathishubham posted this 14 January 2019

Note: Cooling tower starts from a height of 9.17m from ground as columns has a height of 9.17m

height from ground (m) radius (m) thickness (m)

9.17 58.71998481 1.05

10 58.45077875 1.044153913

12.5 57.64576787 1.032

15 56.84976984 1.031590909

17.5 56.06308598 1.031162791

20 55.28602742 1.030714286

22.5 54.51891525 1.030243902

25 53.7620806 1.02975

27.5 53.01586474 1.029230769

30 52.28061906 1.028684211

32.5 51.55670517 1.028108108

35 50.84449475 1.0275

37.5 50.14436954 1.026857143

40 49.45672111 1.026176471

42.5 48.78195074 1.025454545

45 48.12046904 1.0246875

47.5 47.4726957 1.023870968

50 46.83905899 1.023

52.5 46.21999524 1.022068966

55 45.61594831 1.021071429

57.5 45.02736878 1.02

60 44.45471322 1.018846154

62.5 43.89844326 1.0176

65 43.35902455 1.01625

67.5 42.83692562 1.014782609

70 42.33261666 1.013181818

72.5 41.84656813 1.011428571

75 41.37924925 1.0095

77.5 40.93112648 1.007368421

80 40.50266173 1.005

82.5 40.09431064 1.002352941

85 39.70652064 0.999375

87.5 39.33972898 0.996

90 38.99436075 0.992142857

92.5 38.67082672 0.987692308

95 38.3695213 0.9825

97.5 38.09082036 0.976363636

100 37.83507916 0.969

102.5 37.60263028 0.96

105 37.3937816 0.94875

107.5 37.20881436 0.934285714

110 37.04798141 0.915

112.5 36.9115055 0.888

115 36.79957782 0.8475

117.5 36.71235664 0.78

120 36.64996625 0.645

122.5 36.61249606 0.24

125 36.6 0.24

127.5 36.61220718 0.237938144

130 36.64589883 0.237826087

132.5 36.6949721 0.237701149

135 36.75396376 0.237560976

137.5 36.81920808 0.237402597

140 36.88846925 0.237222222

142.5 36.96039863 0.237014925

145 37.03416464 0.236774194

147.5 37.10923758 0.236491228

150 37.18526839 0.236153846

152.5 37.26201957 0.235744681

155 37.33932479 0.235238095

157.5 37.41706451 0.234594595

160 37.49515085 0.23375

162.5 37.57351785 0.232592593

165 37.65211516 0.230909091

167.5 37.73090367 0.228235294

170 37.80985258 0.223333333

172.5 37.88893734 0.211428571

175 37.96813811 0.2

176 37.99984718 0.2

rrathishubham posted this 14 January 2019

Note: Cooling tower starts from a height of 9.17m from ground as columns has a height of 9.17m

```height from ground (m) radius (m)  thickness (m)
9.17    58.71998481 1.05
10  58.45077875 1.044153913
12.5    57.64576787 1.032
15  56.84976984 1.031590909
17.5    56.06308598 1.031162791
20  55.28602742 1.030714286
22.5    54.51891525 1.030243902
25  53.7620806  1.02975
27.5    53.01586474 1.029230769
30  52.28061906 1.028684211
32.5    51.55670517 1.028108108
35  50.84449475 1.0275
37.5    50.14436954 1.026857143
40  49.45672111 1.026176471
42.5    48.78195074 1.025454545
45  48.12046904 1.0246875
47.5    47.4726957  1.023870968
50  46.83905899 1.023
52.5    46.21999524 1.022068966
55  45.61594831 1.021071429
57.5    45.02736878 1.02
60  44.45471322 1.018846154
62.5    43.89844326 1.0176
65  43.35902455 1.01625
67.5    42.83692562 1.014782609
70  42.33261666 1.013181818
72.5    41.84656813 1.011428571
75  41.37924925 1.0095
77.5    40.93112648 1.007368421
80  40.50266173 1.005
82.5    40.09431064 1.002352941
85  39.70652064 0.999375
87.5    39.33972898 0.996
90  38.99436075 0.992142857
92.5    38.67082672 0.987692308
95  38.3695213  0.9825
97.5    38.09082036 0.976363636
100 37.83507916 0.969
102.5   37.60263028 0.96
105 37.3937816  0.94875
107.5   37.20881436 0.934285714
110 37.04798141 0.915
112.5   36.9115055  0.888
115 36.79957782 0.8475
117.5   36.71235664 0.78
120 36.64996625 0.645
122.5   36.61249606 0.24
125 36.6    0.24
127.5   36.61220718 0.237938144
130 36.64589883 0.237826087
132.5   36.6949721  0.237701149
135 36.75396376 0.237560976
137.5   36.81920808 0.237402597
140 36.88846925 0.237222222
142.5   36.96039863 0.237014925
145 37.03416464 0.236774194
147.5   37.10923758 0.236491228
150 37.18526839 0.236153846
152.5   37.26201957 0.235744681
155 37.33932479 0.235238095
157.5   37.41706451 0.234594595
160 37.49515085 0.23375
162.5   37.57351785 0.232592593
165 37.65211516 0.230909091
167.5   37.73090367 0.228235294
170 37.80985258 0.223333333
172.5   37.88893734 0.211428571
175 37.96813811 0.2
176 37.99984718 0.2```

peteroznewman posted this 14 January 2019

After you Reply, look at the buttons on the page and an Attach button appears. You have used that above. That is correct.  The problem with the file you attached is that it is empty.

If you copy text out of Notepad, you can paste it directly into the Reply window where you are typing. That is what I did. Try that.

rrathishubham posted this 14 January 2019

Sir, details of geometry are attached in text format.

Attached Files

peteroznewman posted this 14 January 2019

Create three columns of numbers in a spreadsheet. Copy the three columns out of the spreadsheet and paste into Notepad. Format a line as Preformatted on the pull down in the toolbar. Copy all the lines out of Notepad and paste into that Preformatted line as shown below, except you will have 71 rows.

```height(m)  radius(m)  thickness(m)
0   20  1
2.5 19.5    1
5   19  1
7.5 18.5    0.95
10  18  0.95
```

Alternatively, if you File, Save As the spreadsheet as a Text file and if the file has a .txt file extension, that is another allowed file extension for attaching files to replies. I know you were able to attach a .jpg file at the beginning. You can try to attach a .txt file now.

rrathishubham posted this 14 January 2019

Its a zip file and the file size is 5.36 MB. When I select files and try to upload them, it shows 100% uploaded and it redirects me to same page and the files are not uploaded over there.

peteroznewman posted this 14 January 2019

Do you have a zip file?

What is the file size?

When you click on the Attach button, Browse to the zip file and click Upload.

You will see the file upload. Please try again and describe in detail what happens if it does not attach.

rrathishubham posted this 14 January 2019

Sir, I'm not able to attach the files, can i get your mail id or something where i can send you the files??

peteroznewman posted this 14 January 2019

Only gravity is an axisymmetric load.  Wind and seismic are not.

I recommend you finish the 2D axisymmetric model with just gravity to build some skill with ANSYS.

Please share the details of the thickness and radius as a function of height.  You can insert an image into your reply of either sections of the drawing or a table.  You can also attach files after you post your reply. Put whatever file you have into a zip file and attach the zip file.

rrathishubham posted this 14 January 2019

Yes, i have the drawing that calls out thickness and radius as function of height. Loads to be applied on cooling tower: gravity, wind, seismic

peteroznewman posted this 14 January 2019

Do you have a drawing that calls out the thickness and radius as a function of height?

Please also reply with the load you wanted to apply to the cooling tower, was it only gravity?

I recommend you finish the 2D axisymmetric model before you add in the columns.

Then you can start a New Discussion for the 3D model.

rrathishubham posted this 14 January 2019

Sir, it would be very difficult for me to make the model in ANSYS because that thickness of cooling tower varies at every 2.5m and it has a height of 175m. Also it has varying radius at every 2.5m interval.

peteroznewman posted this 14 January 2019

When you add columns at 20 degree intervals, that's not axisymmetric geometry, now it is a 3D model.

A 3D model can be built from a surface of revolution, plus surfaces to represent the columns.

I expect the iges file only had curves and no surfaces. Create surfaces and try to open that in Mechanical.

rrathishubham posted this 13 January 2019

Sir, I have prepared the model in Revit and exported it to autocad in dwg format further i exported it to ANSYS in .iges file. And when I try to open mechanical, it says no valid bodies found.

rrathishubham posted this 13 January 2019

Thankyou sir. Also sir, I want to create columns at the base of cooling tower at equal intervals. So how do I do that? I want columns at 20 degrees interval.

peteroznewman posted this 13 January 2019

In DesignModeler, you click on the Dimension tab, select Horizontal dimension and click on the line and the dotted line of the Y axis.

rrathishubham posted this 13 January 2019

I will be using design modeler

peteroznewman posted this 13 January 2019

It depends on whether you are using SpaceClaim or DesignModeler.

rrathishubham posted this 13 January 2019

Thankyou sir for your reply. But how do I specify the distance from y axis?