Spring Limitations

1
Spring Limitations

• Spring Will bottom out before plastic
  deformation
• Max Angle of rotation -58
• Factor of Safety from yielding
• 2.2 Spring 1 2.5 Spring 2

2
Monte Carlo Worst Case

• Simulated Variations in the out sourced parts
• Variables Spring Constants, Length of moment
  arm, Yield Strength
• Results Force and subsequently Shear force
• Probability of Failure Calculated using Normal
  Distribution curves. Z value -7.2905
  essentially zero.
• No charts available with Z values that high
• Factor of Safety Spring 1 2.04
• Spring 2- 2.35

3
Monte Carlo /-

• A second and third Monte Carlo was run for -50
  and -79
• Results proved a zero probability for failure for
  all cases involved
• If ankle was not restricted to -58 rotation, and
  thus allowed to transverse the entire cycle,
  probability of failure1.

4
Design Of Experiments Dynamic

• Prototype testing

Testing Procedure
K 1,2
Damping

• Accelerometer
• Excitation by impulse
• Use Data acquisition tools to view s,v,a

Mass
V of FS
?i
5
Design of Experiments Static

• Prototype Testing

Testing Procedure
K 1,2

• Force measured by pulling down on brace against
  spring

6
Full Factorial Design Dynamic
Based on a simulation, similar calculations
will be done with actual test data