Week 4 (10/2/17-10/08/17)

Brainstorming Modules

The figure above shows the different modules from brainstorming. Our team did different modules for 1: Fluid Pump, 2: Flexible/breathable/ comfortable device-skin interface, and 3: Hydraulic/Pneumatic fluids for low and temperature-consistent viscosity.

The figure above shows an idea for a pump system that requires a compressor

The figure above shows three different ideas from our teams pump system

Top Three Modules From Each Concept

The table above shows the top three modules for the fluid pump. Our team agreed that the two parallel cylinder by electric motor gear rotation was the best choice based on our criteria. Our team decided that durability, comfort (defined support wave), and size were important aspects in our decision making.

The table above shows the top three modules for the flexible/breathable/comfortable device-skin interface. Our team agreed that the multi-layered polymer composite was the best choice due to that fact that in obtained friction, comfort, elasticity, durability, and waterproof compared to the two other fabrics.

The table above shows the top three modules for hydraulic/pneumatic fluids for low and temperature-consistent viscosity. Our team agreed with to use air because it is low in viscosity, weight, and reasonable viscosity index.

The schematic above indicates the function of the two parallel cylinder function with motor gears.

Research for Flexible, Breathable, Comfortable Device-Skin Interface:

1. Silk
1. From a sequential lymphedema pump (Patent: US 8206416) [1] the outer material is composed of silk
2. Described as a porous textile, firm, and non-stretchable
3. Porous but firm textile will prevent distention of the cloth.
4. Porosity allows for breathability and management of the moisture created from the individual's skin

2. Cotton
1. From Rehabmart website [2], by the description of posey encapsulating bootie heel guards device, it describes the good qualities of cotton to treat pressure ulcers
2. Helps keep moisture away from the foot
3. Shape conforms to the person's feet
4. However, dermatherapy website [3], describes the disadvantages that cotton may have to treat or prevent pressure ulcers.
5. The disadvantages are that cotton promotes allergens, retains moisture with the progression of time, and causes skin-irritating friction

3. Multi-Polymer Compositions
1. Hulet Smith, the CO-Founder and CEO of Rehabmart [4] recommends wheelchair users to use a urethane honeycomb wheelchair cushion.
2. This thermoplastic cushions are constructed of many individual cells, much like those found in a beehive.
3. Air pockets, made of thermoplastic urethane, can help with distributing the weight and pressure evenly without risk of fluid leakage from within the air pockets.
4. Air flows efficiently through the air pockets and numerous open spaces.
5. These cushion helps against  skin breakdown  by keeping the skin cool and dry.
6. Cushion is lightweight and provides the utmost in shock absorption and sitting support.

Future Shakedown Testing

Materials needed:

• PVC piping
•  60A or 80A urethane rubber
• 3D print molding case
• Air hoses
•  Bicycle pump
•  Valves. 

1. We will begin shakedown testing by making our own tube system. 
2. We will test the material, to see the one which is air tight and we will try to make a torus-shaped air pockets. 
3. We will test to see if our expandable torus-shaped air pockets will be able to connect to the pumping system and make a closed system.
4. We will test to see if our expandable torus-shaped air pockets will be able to contain the planned ratio volume (0%,50%, and 100%  of the total cylinder pump volume).