In Vitro Tests

The tests were carried out as follows:

• The shoe spring mechanism was tested in a 3D simulation environment, Solidworks Simulation.
• The testing involved subjecting the mechanism to forces and constraints that it would encounter during real-life use.
• The shoe spring mechanism was subjected to a range of forces, which were directed downward from the surface on which the patient’s shoe will rest.
• Constraints that were introduced include those for making the sole component immovable and making the maximum shoe frame downward displacement to be that which would make its bottom surface to be level with the sole component.
• The maximum stress on the spring component and any observed deformations were noted down as the mechanism was being simulated.

Results

Fig. Stress Results at 1,500N

The following are the results of stress and strain experienced by the spring component of the mechanism at corresponding values of applied force from the patient’s foot on the mechanism:

The spring required at least 162N to be applied to fully compress it, resulting in a maximum Von Mises stress of 1.476 x 109 N/m^2.

Analysis of Results:

The Von Mises stress and Equivalent Strain increased with increase in the applied force.

The maximum value of Von Mises stress and Equivalent Strain occurred at the heel region of the shoe, which implied that it is where the force applied by the patient’s foot would be concentrated.

As at least 162 N was required to fully compress the spring, it implied that the spring would, for example, reduce the force applied by a patient weighing 50kg by 30%.