University of Puerto Rico at Mayagüez
Department of Mechanical Engineering
Workshop 1
Cantilever Beam
Modified by (2008): Dr. Vijay K. Goyal
Associate Professor, Department of Mechanical Engineering
University of Puerto Rico at Mayagüez
Thanks to UPRM students enrolled in INME 4058
sections 2006-08
Scope
The purpose of this problem is to
demonstrate
how
to
solve
the
displacements and stresses
of a
homogeneous cantilever beam using
ANSYS.
Problem description
Solve a 1-D stress analysis of the cantilever beam shown below
100 N
t = 2 mm
d = 25 mm
500 mm
Starting ANSYS

From your desktop:
Click on: START > All Programs >
ANSYS >
ANSYS Product Launcher.

Here we will set our Working Directory
and the Graphics Manager
Starting ANSYS
1. Launch ANSYS product launcher.
2. Specify working directory and give a job name.
Graphics Setup
•
Click the button:
Customization/Preferences.
•
On the item of Use custom
memory settings type 128
on Total Workspace (MB):
and type 64 on
Database (MB):
•
Then click the Run
bottom.
* This setup applies to computers running under 512 MB of RAM
Go to customization preferences and choose custom memory settings and give values
of 128 and 64 for the total workspace and database memory respectively.
Click Run to start
ANSYS GUI Overview
•
This is ANSYS’s Graphical User Interface window.
Changing Title
To change title go to file and choose change title.
Changing Title
To change title go to file and choose change title.
Give the simplified version a title such as Verification Model.
Preferences
Go to preferences and choose structural and leave the h method as the discipline
options.
Pre Processing
Element type
It is important to define the element type for the beam. For this problem we will use
pipe elastic straight 16. PIPE16 is a uniaxial element with tension-compression, torsion,
and bending capabilities. The element has six degrees of freedom at two nodes:
translations in the nodal x, y, and z directions and rotations about the nodal x, y, and z
axes. This element is based on the 3-D beam element (BEAM4), and includes
simplifications due to its symmetry and standard pipe geometry. To chose this element
type click: preprocessor
Element type
Add/Edit/Delete
Pipe
Elastic straight 16
Real constants
To define the geometric properties we select real constants. The real constant are the
dimensions that must remain constant during the design. These constants are: diameters,
thickness, among others.
For the outside diameter write OD:25 mm and for the wall thickness TKWALL:2 mm.
To chose the real constants click:
processor
Real Constants
Add/Edit/Delete
OD
TK WALL
Material properties
To define the element material properties we choose material models. Our material
will have a Modulus of Elasticity of 70,000 (MPa) and a Poisson’s ratio of 0.33
To add material properties click:
Preprocessor
Material Props
Material Models
Structural
Linear
Elastic
When the pop up window appears, write the modulus of elasticity and the Poisson's ratio
Isotropic
Geometry of the cantilever beam
Now let us build the geometry in ANSYS. The strategy to create the desired geometry
is by first creating the key points where the loads will be applied and then uniting these
key points with lines.
To create keypoints click:
preprocessor
Modeling
Create
Keypoints
Enter the values for keypoint 1: (0,0,0) and for keypoint 2: (500,0,0).
In Active Cs
Now we connect the keypoints to form the bar. To do this click:
Preprocessor
Modeling
Create
Lines
Lines
A pop up window will appear and now you should pick the
first keypoint and then the second and hit the OK button.
The line will look like this:
Element size
To define the element size of the line we use size controls. To do this click:
Preprocessor
Meshing
Size cntrls
Manual size
Lines
All lines
When the pop up window appears, write 20 for the element edge length
Type 20
Meshing
To make the finite element analysis we must first divide the object
into small elements, this is called meshing.
Mesh
Now let us make the mesh using the mesh tool.
On the Main Menu window, select Preprocessor \ Meshing \ MeshTool
Select mesh lines. After the pop up windows appears click
the button that says pick all in that same pop up window.
Then hit the OK button.
Boundary conditions
For keypoint 1: constraint all DOF’s (displacement value = 0)
To apply the BC click:
Preprocessor
Loads
Define Loads
Apply
Structural
Displacement
When the pop up windows appears select the first keypoint and
hit the ok button.
Pick this
Keypoint keypoint
1
On keypoints
In order to make it a cantilever beam we must
constraint all degrees of freedom to the first key point.
Type 0
Loads
The next step is to apply the load vertically downward with a force of 100 N to
keypoint 2. To apply the load click:
Preprocessor
Loads
Define Loads
Apply
Structural
Chose this
keypoint
Pick
keypoint 2
Force/Moment
On keypoints
We must apply the load in the negative Y direction. That’s the reason we will
enter a negative sign before the force value in the pop up window
Type -100
The load will look like this:
Solution
Analysis type
To start the solution phase it is important to set the type of analysis.
We will perform a static analysis since we only want stresses and
deflections. To select analysis type click:
Solution
Analysis Type
New Analysis
Static
Ok
Solve
Now we proceed to solve the problem. To do this click:
Solution
Solve
Current LS
Note: When the pop up windows appear click the OK button.
A pop up window that says: “Solution is done” will appear
after ANSYS finishes solving the problem. Click close
Post Processing
FEM Solution & Plotting Results
• Now we already developed the geometry, Loads & Displacements
and the meshing. We will start with the finite element analysis and
obtain the displacements and stresses on the key points.
• After make the FEM solution we are able to plot the results, in this
case the displacements and stresses.
Reading Results
To read the results click:
Solution
General Postproc
Results summary
Click
here
Read Results
First Set
View deflection results
To view the results of the applied load we use plot results of the deformed shape.
Click:
General postproc
Plot results
Deformed shape
Chose
def+Undeformed
The deformed shape plot will look like this:
To see the results of the deflection we use the nodal solution. Click:
General postproc
Plot results
Contour plot
Nodal Solution
Chose
this
The plot will look like this:
View stress results
To plot the stresses of the beam under the applied load we choose define table under
element table. To do this click:
General postproc
Chose Stress
Element table
Chose Von
Misses
To view stress results click:
General postproc
Plot Elem Table
The plot will look like this: