3. CONTENT OF THE PRESENTATION
• Introduction on the project and definition of key terms
• Design process
• Parameters of the existing and New freight train secondary suspension
• 3D model using AUTOCAD
• FEM and Applied Force
• Simulation using ANSYS
• Result and comparison
• conclusion
4. DEFINITION OF KEY TERMS
Freight train: also called goods (cargo) trains are train that are used to transport
goods but not passenger.
Secondary suspension: In freight trains connects the body attached bolster of the
car with the material side frame of the bogie to resist the shock caused by the
wheels on the bogie frame and body also called bolster springs.
Design a secondary suspension for freight: it is to design a secondary suspension
in considering of component need the freight train.
5. 1. Step one: Find a resource and
Evaluate
All measurements are taken from
model PW2 box wagons of Ethio-
Djibouti rail ways.
Analysis results concludes that steel
is an optimal material for Helical coil
springs that was less deformed, less
stressed and is safer than other
materials on applied loads.
For this project we used Microsoft
word, AUTOCAD and ANSYS.
DESIGN PROCESS
6. 1. Step one: Find and Evaluate the resource
Secondary Suspension spring arrangement
Have 9 outer Spring and also inner spring on
one side of the train bogie.
Below the bolster and then fixed to the side
frame.
2. Step two: Carefully study the problem
and make sure you have a clear
understanding of what needs to be done
Taking an existing design of secondary
suspension of freight train and then manipulate
manipulate the parameters for better design so
that, the change can add some value.
DESIGN PROCESS
7. 3. Step three: Imagine by asking WH question
how can we increase the efficiency, should I change diameter, the material, …
4. Step Four : now start to sketch ideas
Choose to change the diameter of the spring
DESIGN PROCESS
8.
9. Parameter Existing Material New Material
outer diameter(left & right) 135mm 140mm
inner diameter(left & right) 85mm 97mm
outer diameter(middle) 134mm 134mm
inner diameter(middle) 87mm 87mm
Height (left & right) 252mm 252mm
Height (middle) 220mm 252mm
Number of Turns(for all) 6 6
Applied load(for all) 3950N 3950N
Freight weight 95.2t 95.2t
DESIGN PROCESS
10. DESIGN PROCESS
Material selection
For both the existing and new design of the secondary suspension we took the default material
type and its property which is placed at the ANSYS software called Structural Steel.
On the table show below there is its material properties
11. FINITE ELEMENT METHOD(FEM)
The FEM approaches problem by splitting the body into a number of small element that
are connected together at node. This process is called Discretization and the collection of
nodes and element is called The Mesh.
12. APPLIED FORCE
To calculate the applied force:
Given:
the train is at rest and the force is equal
distribution trough out the train system
Total mass= 94,800Kg
Gravity=10 𝑚
𝑠2
Solution: 𝑤𝑡 = 𝑚𝑡 ∗ 𝑔
Divide the total weight in four to make it
uniformly distributed to each side.
Each side have 9 spring
Direction of the force
13. FATIGUE TOOLS
The Result of the two design is generated by using the three fatigue tool:
Life cycles
Damage, and
Safety factor.
Life cycle: the material can with stand or can last a repeated impact of this minimum
value.
Damage: which means at what level of impact will the material will be damaged.
Safety Factor: tells us that it is safe to be implemented in real world
17. CONCLUSION
COMPARSION PARMETER(UNIT) Existing Design Value NEW Design Value
DAMGE(CYCLE) max(47815) max(7830.1)
LIFE CYCLE(CYCLE) min(20914) min(20914)
SAFTEY DESIGN FACTOR 0.40774 0.6682
18. CONCLUSION
Hypothesis of the failure points:
the diameter is taken by human being
measuring in real time which can lead
to error.
the material we used is structure steel
on ANSYS which is different material
we use for the real freight secondary
suspension.
