156B Week 8

Overview of Status of Analysis, Design, Fabrication, Tests, etc.

Accomplishments from Previous Week

● Picked up and tested 3D printed flexible material from Chris Cassidy (Garrett and Miles)

● Insole bodyweight stomp testing (Garrett and Miles)

● 2 new design prototypes with rubber and neoprene (Ho)

● Partial field testing of new prototypes (Jordan)

● Brainstorm/CAD of a protective cap for toes; unsure if will incorporate into design (Jordan)

● Cost estimation based on materials used: $26.58 (Jordan)

Goals for Next Week (list names after each item). Use specific and measurable objectives.

● Change rubber sheet to be more flexible (All team brainstorm)

● Create cupped insole to reduce drag (Garrett and Miles)

● Rigorous field testing of prototypes (Jordan)

● Properly cutting insole to standard shoe size (Jordan)

● Applying a new design of the rubber into the prototype (Ho)

● Refining cost estimate (Entire team)

Sponsor Comments from Last Meeting and Actions Taken to Address these Comments (indicate date of comments and if via email or in person)

● Considering moving to plastic zippers instead of metal zippers

● Test flexible 3d print with new barb

● Cupped sole

● Ho's prototype is easier to put on but less uncomfortable

○ The toe area is uncomfortable)

● So far we're using the 7 and 9" inch zipper

● Overlapping rubber that moves as you move

● Could try one piece of rubber but cut into with slits to allow it to bend more. It's all a tradeoff. Sacrificing 5% stingray resistance for wearability

● Multiple layers of rubber

● Find/make rubber in the shape of a saddle point

● Ask Darren about the process of curing rubber, possibly get some of his

● How it's made rubber, might give us insight into cured vs. uncured rubber

● What happened to test leather?

Instructor Comments from Last Meeting and Actions Taken to Address these Comments (indicate date of comments and if via email or in person)

● Search “elastomers” specifically

● We need zippers that can handle saltwater

● Visually the oomoo looked too flexible

● Simple household caulks would be easy to obtain and test

● Low durometer means it'll be more flexible, certain caulks and sealants will say their durometer

○ Elastomers are usually D durometer (40D)->(90D)

● try out different durometers of EVA polymers (hot glue)

● If we decide hot glue works the best, research why it works the best, and maybe test the durometer

● if something looks promising, look at an industrial way of getting it

● Smooth-on is like oomoo but has more technical specs

● polyurethane comes in a lot of durometers

● Try searching just for urethanes

● test EVA (hot glue) in salt water

● Search"chemical compatibility" of salt water and hot glue

● Use Dow or Dupont and call and ask about the chemical compatibility, or look for specs on their website. Eastman rubber is also a common supplier.

Risks and Areas of Concern

● Top contour of the foot against rubber layer

● Professional final prototype

● Drag reduction

● Durability testing

Budget (list amount spent and amount remaining)

● Bought more zippers and rubber

● Previous amount spent: $305.77

● New amount spent: $339.93

● Remaining budget: $660.07

Progress on Report and Webpage