0.7 0.8 0.9 1 1.1 1.2

0

5

10

15

20

25

30

time(s)

dis

pla

ce

me

nt(

mm

)

Front Wheel Displacment

2500N

3000N

3500N

4000N

4500N

5000N

0.7 0.8 0.9 1 1.1 1.2 1.3

0

5

10

15

20

25

30

35

time(s)

dis

pla

ce

me

nt(

mm

)

Rear Wheel Displacment

2500N

3000N

3500N

4000N

4500N

5000N

Dynamic Analysis: MSC ADAMS/View

Static Analysis: ANSYS

3-D Modeling: NX5 Objective: Choose a suspension system reasonable for a low-cost, multi-passenger vehicle. Result: A beam axle complete with a Watt’s Linkage was implemented in the rear-end suspension.

Result: MacPherson Struts were implemented in the front-end suspension

Objective: Determine if the spring stiffness and damping coefficients found using hand calculations gives the vehicle a resonant frequency between 1.5 -2.3 Hz.

Figure 13. Full suspension system, with vehicle frame, in

ADAMS/View.

Figure 14. Simulation of the vehicle going over a bump on

the road.

Results: At different speeds and bump sizes the resonant frequency of 1.667 Hz was found when the front spring stiffness

was 16 N/mm with a damping coefficient of 30 N-s/mm and the rear spring stiffness was 18.7 N/mm with a damping

coefficient of 30 N-s/mm.

Table 1. Maximum forces between the bump and

the tire to use for the static analysis.

Table 2. Maximum spring forces collected in

ADAMS and used for the static analysis.

Contact Force

Speed(km/hr) Bump(cm) Front Force(N) Rear Force(N)

8 10 8774 8723

16 10 13347 13818

32 10 22158 21534

64 2.5 23145 26844

96 2.5 49291 58230

Spring Force

Speed(km/hr) Bump(cm) Front Force(N) Rear Force(N)

8 10 3399 3159

16 10 6228 5499

32 10 7998 12115

64 2.5 10000 15942

96 2.5 13672 27388

5 10 15 200

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

Vehicle Resonant Frequency

Frequency (Hz)

Ya

w, P

ith

, a

nd

Ro

ll (D

eg

ree

s)

10cm bump @8km/hr

10cm bump @16km/hr

10cm bump @32km/hr

2.5cm bump @64km/hr

2.5cm bump @96km/hr

Figure 6. Max Stress - Steering Force. Figure 7. Max Stress - Braking Force. Figure 8. Max Stress - Force from a Bump.

Objective: Determine stresses due to the maximum

steering force, braking force and force caused by a

bump in the road.

Results: The stresses were under the tensile strength

of 825 MPa for all cases. When the number of elements

were increased, the stresses converged so the results

from the models were determined to be accurate. Figure 5. Front Suspension Mesh

Objective: Determine stresses due to the

maximum braking force, a force caused by

a bump in the road on one tire and the force

caused by a bump in the road acting on both

tire.

Results: The stresses were under the tensile

Strength of 825 MPa for all cases. When the

number of elements were increased, the

stresses converged so the results from the

models were determined to be accurate.

Figure 10. Max Stress - Braking Force. Figure 11. Max Stress - Force from a Bump. Figure 12. Max Stress - Force from Two Bumps.

Figure 9. Rear Suspension Mesh

Named after Earle S. Macpherson, the Macpherson Strut is distinguishable by the coincidence of the upper

steering pivot point with the damping mechanism.

Also known as a Parallel Linkage, the Watt’s Linkage was invented by James Watt in the late 18th century. It is a

simple three-bar-linkage designed with the intent to restrict locomotive pistons to linear motion.

Figure 1. Macpherson Strut Figure 2. Integration of Front Suspension Figure 3. Beam Axle Suspension Figure 4. Integration of Rear Suspension