Upload
ludi-pas
View
214
Download
0
Embed Size (px)
Citation preview
8/9/2019 Cylindrical Tank Tutorial
1/11
How to Construct and Analyze a Cylindrical tank in Autodesk
PART I: Creating your tank
1)
Open Autodesk Inventor Fusion 2013
2)
Click New
3)
HomeSketchNew SketchSelect XY plane4)
SketchCenter-Radius CircleSelect (0, 0) as your center pointenter outer radius of tank
click enter until circle changes color
5)
Select the circle. Make sure to click inside the perimeter of the circle instead of selecting the
edge.6)
An extrude icon will pop up. Select extrude. Enter inside height of tank. Double click Enter
8/9/2019 Cylindrical Tank Tutorial
2/11
7)
SketchCenter-Radius CircleSelect the middle of the top of the tank as the center-->Enter in
the inner radius of your tankClick Enter twice
8)
Select the inside circleextrudeenter the negative value of your tanks height to cut through
8/9/2019 Cylindrical Tank Tutorial
3/11
9)
SketchCenter-Radius CircleDrag mouse to the upper rim of the tank and hold shift to lock
sketch planeSelect the center point as the center of circledrag radius until it locks with the
outer edgeEsc
10)
Hold down shift and select both the inner and outer circlesextrudeenter thickness for your
roof slabEnter 2xrepeat for the bottom of the tank
8/9/2019 Cylindrical Tank Tutorial
4/11
At this point you should have a hollow, symmetrical cylinder that you cannot see the inside of.
Save the part and Select Simulation Mechanical in the Home tab. This will open Autodesk
Multiphysics, allowing you to stress and analyze your tank.
8/9/2019 Cylindrical Tank Tutorial
5/11
PART II: Loading your Tank
1)
Once Multiphysics opens, it will prompt you to choose analysis type. Select the default
Static Stress with Linear Material Models
2)
In the FEA editor column on the left of the screen, right click Element Type under Part 1
and select Brick. Edit Element DefinitionMidside NodesIncludedOK
3)
Right Click MaterialConcreteSelect the concrete strength you prefer or alter its
conditions
4)
Go to the Mesh tab3D Mesh SettingsMesh Type= SolidMesh Size= approximately
70%Mesh Model
8/9/2019 Cylindrical Tank Tutorial
6/11
5)
In the left panel, expand the surfaces tab and make invisible the outside of the tank by
holding control and selecting surfaces 1,2,4,5,6, right-clicking and unchecking visibility. This
should leave just the inside of the tank visible.
6)
Select the inside surface of the tankRight ClickAddSurface hydrostatic Pressure
8/9/2019 Cylindrical Tank Tutorial
7/11
7)
Enter the fluid density of water (62.4 lbf/ft^3), Select the Z button in Fluid Depth Direction
(V), and enter the coordinates of the point that would lie on the top of the water in your
tank. For this tutorial we used X=0, Y=inner radius of tank, Z=height of tank. Select OK
8)
Make the rest of the surfaces visible again
8/9/2019 Cylindrical Tank Tutorial
8/11
9)
Constrain the bottom surface by selecting the bottom surfaceRight ClickAddSurface
General Constraint-->Fixed
10)
To add rebar, complete the following steps
11)
Select DrawLineUnclick Use as ConstructionSelect the location on the mesh where
you would like to add the rebar (The maximum hoop stress in a tank occurs approximately
1/4-1/3 up the height of the tank. This is the best place to reinforce with rebar).
12)
Unfortunately, the only way the lock the rebar into place while still staying attached to the
tank is to manually select each vertex in a horizontal line all the way around the tank. If you
skip nodes, the rebar wont lock itself to the tank there, causing irregularities in geometryand adding stress concentration.
8/9/2019 Cylindrical Tank Tutorial
9/11
13)
Once youve created a line circling the tank, edit its properties in the left columnPart
2Element Type = BeamElement Definition=Inertial Properties of your
RebarMaterial=Edit values for your rebar
You may add as many bars of rebar as you want. For the purpose of this tutorial we will only
use one though.
8/9/2019 Cylindrical Tank Tutorial
10/11
PART 3: Analyzing your tank
Your tank simulation is now ready to run. But first go to setupGravitySet for standard gravityOK
Select AnalysisRun Simulation
*The more refined your mesh size is, the longer itll take for Autodesk to simulation your tank. With the
mesh size of 70% we picked before, Autodesk should only take about a 1:30
It may be useful to add a slice plane to examine the inside of your tank
Select Results OptionsSlice planesAdd Slice planeYZ plane
You can also fool around with how the tank visually appears by going to ViewVisual Style
Personally I prefer shaded with mesh.
At this point its up to you how you would like to analyze your tank. Its important to notethat while
normally, Von Mises is a good determination of maximum stress in your part, it is not useful here
because of stress concentration at corners and connection points. Hoop stress is what youre most
concerned about in tanks. Either the YY or XX tensors will give a good approximation of hoop stress. To
find the stress the rebar alone undergoes, select the Beams and Trusses option in Result Contours
8/9/2019 Cylindrical Tank Tutorial
11/11
It might also help to change the units to inches. Thus stress will appear in psi.
For this tutorial, the tank undergoes a maximum tensile stress of 3.5 psi and a maximum compressive
stress of 12 psi. Considering the yielding stress of concrete is over 100 psi, it is reasonable to conclude
that this tank will not come close to fracturing due to the hydrostatic loading from the water it contains.
This tutorial was created by:
Engineers Without Borders
Lehigh University ChapterProject Class, Tank Group, Fall 2012
For questions contact:
Zachary Pelli
B.S. Mechanical Engineering 2014
Lehigh University
203-223-4067