1. Feet for All
Spring
Deliverables 2
Kevin Fontenot, Hayden Slack, Charles
Sprague, Vladislav Voziyanov

2. Overview
• Testing
o Methods
• Data Collection/Analysis
o Bushings
• Modeling
o Deflection
o Range of Motion

3. Testing
• Run static load testing based on ISO 10328 on first
prototype w/ SACH foot
• Run Static load testing based on ISO 10328 on
second prototype w/ SACH foot
• Compressive testing on Bushings

4. Prototype Testing
• 1st iterative design • 2nd iterative design
3in 3in

5. Bushing Testing
• 90A • Collect data using
• 80A compressive testing in
• 60A order to develop a
method for selecting
appropriate hardness.

6. 90A Test
1in
Compressive testing done on a 90A bushing. Deflection
is hard to see.

7. 80A Test
1in
Compressive testing done on an 80A bushing.
Deflection can be seen.

8. 60A Test
1in
Compressive testing done on a 60A bushing. The
elasticity of this hardness can be seen here.

9. Modeling

10. Theoretical Model of Deflection as
a Function of Force
The theoretical model of deflection as a function of force. This model
shows that as the Shore A hardness increases deflection decreases. With
this model deflection based on force can be predicted.

11. Theoretical Model of Range of
Motion as a function of Force
The theoretical model for range of motion as a function of force. This
model allows one to choose bushing hardness based on weight.

12. Data Analysis
• Bushings
o 90A
o 80A
o 60A
• Deflection (in) as a
function of force (lbf)
• Experimental vs.
Theoretical
• Percent Difference

13. 90A Data Compared to the
Theoretical Model
The 90A data compared to the theoretical model is not accurate. The
data itself is fairly precise however it appears to be more closely
associated with a hardness of approximately 80A.

14. 80A Data Compared to the
Theoretical Model
The 80A data compared to the theoretical model is accurate. It appears
to have the same slope and the data is grouped around the theoretical
model.

15. 60A Data Compared to the
Theoretical Model
The 60A data is precise but compared to the theoretical model it appears
not to be linear. Unlike the other hardness models this one shows tight
groupings during low forces which spread out as force increases.

16. Average % Difference of the
Analytical
30%
90A, 25%
25%
20%
Average % Difference
15%
10%
90A-80A, 8%
5% 80A, 4%
60A, 1%
0%
Durometer Hardness (Shore A)
This is the average % difference of the theoretical models
compared to the models generated from data collection.