Embedded Files
Introduction
Throughout our research, development and testing of our shoe we discovered many different constraints that were not immediately clear and easier solutions to the criteria given. We found ideal materials for all parts of the shoe and we found ideal designs the shoe as well. Some of these designs and changes we were able to implement but we would believe would make a better design. So we complied things we would do differently in our design and testing to get a better product.
Material Recommendations
For the future of this project we suggest that the fabric body of the shoe is made from Nomex (Figure 1) for its fire resistant properties. The shoe will have a seam that goes down the center of the shoe which creates a strap. Perpendicular to the seem will be three velcro strips with the loops underneath the top flap, and hooks on the top of the bottom flap. The sole should be made of a pour-able silicone rubber which is molded. The sole should be glued on with a sil-poxy glue which is meant to glue things to silicone.
Figure 1- Nomex Fabric
Tread Recommendations
In the future we recommend any type of sole ridge design it doesn't have to be too complex (Figure 2). The durability needs to be accounted for and if it can involve less material that is also good. The more minimalistic the design is the less material and weight is needed to be launched to space. The durability is also needed so less replacement is required.
Figure 2- Our simple tread design
Testing Recommendations
5.5" x 6" sheet friction test three COF #2 test
(Figure 3) Data from angle test
What to fix/change:
This test was very primitive and didn't do a good job of isolating all factors that would affect the coefficient of friction. Things like humidity, and static charge weren't measured. While this result helped guide our original design it wasn't as accurate as possible. Things that would've helped is multiple trials minimum of 5 each interval. At the time we also used a thin piece of plastic which may have influenced our numbers compared to a thicker shoe that would later be on the shoe.
Shoe friction test three COF #2 test (angle test)
(Figure 4) Incline at 10 degrees
(Figure 5) Incline at 20 degrees
(Figure 6) Data from angle test
What to fix/change:
This test was better than the previous but was still flawed and once again didn't do a good job of isolating all factors that would affect the coefficient of friction. Things like humidity, and static charge weren't measured. While this result helped guide our original design it wasn't as accurate as possible. Things that would've helped is multiple trials minimum of 5 each interval.
Pulley test
(Figure 7) Data for pulley test
(Figure 8) Weight pulls on shoe equivalent to frictional force
(Figure 9) Weighted string pulling on shoe parallel to ground
What to fix/change:
This test showed us a more accurate coefficient of friction. While this test was better it was still flawed in a couple of ways. The amount of trials per weight needed to be increased to get a better range of data and to make sure there was no anomalies. We should've also measured the amount of dirt and particles on the silicone before during and after testing since these could significantly reduce the friction.
Harness test
(Figure 10) Our testing subject in the harness setup
(Figure 11) Pulley system above with a mechanical advantage of 7 holding 5/6 s of our subjects weight.
What to fix/change:
To improve this test we should've added the harness to a track along the ceiling which allow the person to simulate a more realistic walking scenario. In this test we would lay out a couple rolls of the gym mats lined up with the track simulate walking in low gravity. We would also suggest finding a different mat for the testing. While our current mat works quite well the friction is less than we had originally planned for. To increase the friction we would suggest finding a silicone mat (Figure 3) that a rougher tread and a lower durometer to increase the friction and improve the shoes effectiveness in environments with foreign debris.
(Figure 12) Example of a different silicone mat
Varied Weight Test
(Figure 13) Data from varied weight test
(Figure 14) Weights evenly distributed across shoe
(Figure 15) Venier force sensor clipped to shoe
(Figure 16) Experimental setup
(Figure 17) Graph of data
What to fix/change:
Something we overlooked in this test is weight distribution. While we put the weight over the whole shoe we didn't test whether or not different weight distributions would increase the coefficient of friction or not. We also didn't mark down what the status of the silicone sole and floor mat was, this means that it could've accumulated dust and dirt which would've affected the data.
Static test
(Figure 18) Data from static test
(Figure 19) Sling psychrometer
(Figure 20) Electroscope
(Figure 21) Humidity Measurement
What to fix/change:
This test was decent although there were some problems with the test. There was some static build up in the surface that was rubbed against the table as the table has a unique charge when compared to the material used. This should have been prevented. We did well when accounting for the humidity but there were a couple small outside variables that may have affected the charge of the material.
Multi size test
Mens - 7
Mens - 9.5
Mens - 11
Mens - 12
What to fix/change:
This test was incredibly simple as it was simply testing how it would fit on different size feet. The data we took was completely qualitative as it was simply the question of "How comfortable is it?" and the data really couldn't go much beyond that. We could have used more feet of different shapes and sizes but we still got a range that we could work with.
Wear Test
(Figure 22) Original sheet after testing
(Figure 23) Before test
(Figure 24) After300 rubs
(Figure 25) After 1000 rubs
What to fix/change:
This test was incredibly simple as it was simply rubbing two pieces of rubber together and taking qualitative data on the results. There isn't to improve here but there are a couple things. We could use something to ensure that every stroke was the exact same force and we could also measure this constant force. We could use some means to make sure that the piece of rubber is properly grounded rather than relying on the fact that it has a lot of friction with the surface it is on.
Conclusion
While we were able to implement our original design we still are improving on the design to make it better. These recommendations would serve to improve the functionality of our current shoe and its feasibility. While our previous floor mat made from our pourable silicone had the highest friction it wasn't feasible to use it as our flooring because of the durability and the fact that it had to be made custom.
Page updated
Google Sites
Report abuse