156B Week 3

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

• • Continuing prototype testing

    • Woven layers

    • “Hinged” layers

    • RTV sealant

    • Leak-proofing nozzle-plastic junction for heat-sealed plastic prototypes

    • Tygon tubing extension and sealing of the vacuum intake in order to avoid the need for  a constant vacuum supply

  • Parts Arrived:

    • RTV sealant gun/plunger

    • Polystyrene beads

    • prototype supplies: silicone sheets, nozzles, and hex nuts

Accomplishments from Previous Week

• • Fabricated and tested flour-only prototype and sandpaper-only prototype

  • Design Proposal presentation shared with class and sponsor

  • Tested new heat sealed plastic prototypes

  • Tested commercial vacuum sealed bags

  • Came up with new paper designs that will allow avoiding stresses due to bending

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

• • Fabricate heat-sealed plastic-encased prototypes with nozzles that perform as well as the silicone-encased prototypes  

    • Find a solution for cutting smooth, circular holes in laminate plastic (Olesya)

    • Find a way to prevent or reduce leaking around nozzle-plastic junction (Kerrianne)

  • Fabricate and test three new layer designs

    • Woven (overlapping) layers (Brian)

    • Layers with a hinge (crease) that allow two semicircular halves of the prototype to close over the arm (Brian)

    • Layers supported by copper wire to maintain a cylindrical structure (Olesya)

  • Develop prototypes replacing the nozzle with tubing

    • Prevent or reduce leaking around tube-prototype encasement junction (Dylan)

    • Find appropriately-sized, ball-valve/nozzle connector (Dylan)

  • Fabricate a prototype with polystyrene beads (Kerrianne)

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

• • 1/23/18 - In Person

    • Focus experiments and tests on novel ideas instead of what has already been tested

    • To keep results consistent across past prototypes, keep the mass of each prototype consistent (rather than the volume or layer number)

    • Suggested looking into shape memory alloys for conformability

    • Would like us to eventually consider a fingertrap method, especially with a triaxial weave, where each strip would have its own plastic enclosure

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

• • 1/18/18 - In Person (Design Proposal Presentation)

    • Consider a prototype that remains cylindrical even without a vacuum, i.e. using wire to maintain a cylindrical structure

  • Focus on increasing thickness, or test using the same thickness

Comments from Other Students in the Class (indicate date of comments and if via email or in person)

• • 1/18/18 - In Person (Design Proposal Presentation)

    • Reassess which orientation and grit size of the sandpaper layers would provide maximum stiffness in a layer jammer (double sided sandpaper?)

    • Consider a layer jammer that alternates material (i.e. sandpaper with rubber)

Risks and Areas of Concern (what would prevent the project from being completed?)

• • N/A

Resources or Information Required but not Available

• • N/A

Schedule

• • Finish the new enclosure manufacturing

  • Test new design ideas to see if it increases performance of the product

Budget (list amount spent and amount remaining)

• • Amount remaining $2289.22, $110.78 spent

Progress on Report and Webpage

• • Impact on Society section ongoing