University of Puerto Rico at Mayagüez
Department of Mechanical Engineering
Workshop :Bicycle Frame
Design (Optimization)
Modified by (2009): Dr. Vijay K. Goyal
Associate Professor, Department of Mechanical Engineering
University of Puerto Rico at Mayagüez
Thanks to Josymir Lopez Ferrer , enrolled in INME 4058
section 2008
Problem Description
This is a simple static analysis of a frame of bicycle using a hollow aluminum
tube. The schematic dimensions of the bicycle are shown in the figure 1.
Initially, the flowing cross-sectional dimensions are used for all frames:
Outer diameter φ = 25mm and Thickness t =2mm
The material properties of aluminum are:
.
Material Properties
Values
Young’s Modulus (E)
70 Gpa
Poisson’s Ration (ν)
0.33
Density (ρ)
2,580 kg/m3
Ultimate Tensile Strength(σU)
210 Mpa
Elongation at Break
10 %
Problem Description (cont.)
Even if the bike is under the dynamic loads, only the static
design criteria is considered here: due to vertical bending.
Vertical bending test:
When an adult rides the bike, the nominal load can be
estimated by the vertically downward load of 600N at the
seat position and a load of 200N at the pedal crank
location. When a dynamic environment is simulated using
the static analysis, the static loads are often multiplied by
a certain “G-factor”. In this design project, use G = 2. Use
ball-joint boundary condition for the front dropout (1)
and sliding boundary condition for rear dropouts ( 5 and
6 ).
Problem Description (cont.)
We want to optimize the bars. For this reason, we are assuming that the
following bars will have the same cross-sectional areas:
bars 1 and 4 will have the same cross-sectional area, defined by real constant 1
bars 2 and 3 will have the same cross-sectional area, defined by real
constant 2
all other bars will have the same cross-sectional area, defined by real
constant 3
.
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
Working Directory Setup
•
Select the Working
Directory and type
the name of work
shop on 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.
Step 1: Build the model
We have two option:
1.
We
can
fun
the
previous
tutorial
and
save
the
output
VerticalBendingTest.txt
2.
.
Or, read the VerticalBendingTest.txt (it runs the tutorial directly)
in
Step 2: Go to Design Optimization
1.
Go to Design Opt> Analysis File>
a)
Create
b) Assign… File name is: VerticalBendingTest.txt
2.
Now Go to utility menu and read the VerticalBendingTestOptimization.txt
file (read input)
3.
Go to Design Opt> Design Set>List (choose ALL sets). This gives you the
various iterations
.
Step 3: Now use this model
From this point on you can use this model to perform all other analysis.
.