MENG 421 Assignment 10

Ansys: Stressed plate with hole

MENG 421 | Class assignments | 1 2 3 4 5 6 8 9 10 11 12

Lecture notes -- Milestones, 1, Failure, Plane42, Plane55, Plane82,
End support, Full support, Correct, Wrong, Capture

In the previous lesson, Assignment 9, you created a model of one-quarter of a plate with a hole, applied the default mesh, and then refined the mesh around the hole. In today's lesson you will apply the constraint and load to this plate and determine the resulting displacement and stress. You will create the second and third figures below. Then you will animate them.
If you find the lower part of a window off the screen, hold the Alt key while pressing the Space Bar. Release both keys and press the M key. Now you can move the window by pressing the cursor arrows. For example, press the up arrow to raise the window. Press Enter when the window is in the new position or press the Esc key to cancel this action.
Be careful how you constrain the plate. The lower edge can move right but not down. Similarly, the left edge can move up but not to the left. You must be careful to chose one-dimensional (roller) supports not only at the ends but also at each node. If the supports are incorrect, the edges will not be straight.

Before starting Ansys be sure that your directory has at least 1.5 MB of free space. Otherwise you won't be able to save your work.
Make the changes you have in the past lessons including the clearing of C:\WINDOWS\Temp.
There are two ways to resume your work from Assignment 9. You can start with the binary DB file. Alternatively, you can edit out the beginning lines of your most recent batch file Plate52.a that you made.
Start Ansys
Continue with your most recent version
- If starting with your text file, edit out the top lines, then Utility Menu: File | Read Input from and point to your file
- From the binary file DB -- Utility Menu: File | Resume from (steer to your Ansys files) | Plate82.db | OK
You should have a black background. If not, type the Ansys command:
```
/color,pbak,off
```
Then click the Plot menu and pick Replot.
Utility Menu: File | Change title | (Click at end, change date, add Part 2) | OK
If the elements don't show, Utility Menu: Plot | Elements
Constrain the lower edge in Y direction
- Main Menu: Solution
- Solution: Loads (Define Loads, Ver 8) -- Apply
- Apply: Structural -- Displacement
- Displacement: On Keypoints
  Pick two places along bottom edge, the lower-right corner and lower-left corner at arc. If you make a mistake, click unpick and pick the wrong place. Then click pick.
- Apply U (small menu): Check that count is 2 | OK
- Apply U (large menu): DOF -- UY | Value 0 | Expand displacement, click for Yes (so all nodes on edge are also constrained) | OK (Check for triangles at each end pointing up)
Constrain the left edge in X direction
- Displacement: On Keypoints
  Pick two places along left edge, upper-left corner and lower-left corner at arc.
- Apply U (small): Check that count is 2 | OK
- Apply U (large): DOF -- UX (unpick UY) | Value 0 | Expand displacement Yes (so all nodes on edge are also constrained) | OK (Check for triangles at each end pointing right.)
- Close Displacement menu.
Apply pressure load
- (Solution: Loads) Apply | Structural -- Pressure
- Pressure: On lines
- (Pick middle of right edge)
- Apply PRES (small menu): check for count = 1 | OK
- Apply PRES (large menu): VALUE 300 | OK
- Check for arrows on right edge
- Close Pressure and Apply menus.
(Main Menu:) Solution:
- Solve -- Current LS
- /STAT: Review information there | Close
- Solve Currrent Load: OK
- Information: Close
- Check your figure for load triangles on lower and left edges. Your plate should look like this. Notice that the supports are located not only at the corners of each element, but also at the midpoints. Here's an enlargement. This shows that you are using 8-node quadrilateral elements.
- Close Solution menu.
Main Menu: General Postproc
General Postproc: Read Results -- Last Set
General Postproc: Plot Results
Plot Results: Deformed Shape
Plot Deformed Shape: Def + undeformed | OK
Your plate should look like this
Check that you applied the constraints properly. Your figure is one-quarter of the entire plate. So the left and bottom edges are constrained by the remaining three-quarters of the plate. These edges must be straight and must remain that way. That is, the lower edge cannot move up or down (a UY constraint) and the left edge cannot move left or right (a UX constraint). On the other hand, if your figure looks like this you did not constrain the bottom and left edges correctly. Please start again at the top of this page.
When the figure looks correct, capture it.
Copy file.log and name it Plate19b.a
Utility Menu: File | Save as | plat82d.db | OK
To animate: PlotCtrls | Animate | Deformed Shape | Def + undeformed | OK
To see a 625KB animation of the deformation, ¤ click here.
(General Postproc) Plot Results: Contour Plot -- Nodal Solu
Contour Nodal: Stress ( on left), von Mises SEQV (on right) | OK
Your plate should look like this. When the figure looks correct, capture it.
Copy file.log and name it Plate24b.a
Utility Menu: File | Save as | plate82s.db | OK
To animate: PlotCtrls | Animate | Deformed Results | Stress (left) -- von Mises SEQV (right) | OK
Notice that the highest stresses (in red) are at the top of the hole. You can click Stop and then successively click Next to single-stop the pictures. To see a 600KB animation of the stress, ¤ click here.
Toolbar: Quit | Quit - no save | OK
Assignment
Create a cover sheet describing what you did including the refinement of the the element size. Edit the two graphics as you did last time by picking negative, gray scale, and brightness adjustment. Include a printout of your typed commands. Turn in the package as specified at the lab.

MENG 421 | Ansys -- Lecture 1 -- Class assignments | 1 2 3 4 5 6 8 9 10 11 12