156B Week 2

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

• • Tests to run:

    • Strain rate of materials (Instron)

    • Durability of external cast casing and adhesive used for the casing

• Analysis:

  • • Compare strain rate of materials

    • Hypothesize improvement of resistive tensile force for layers of different materials

• Fabrication methods to investigate:

  • • External casing:

      • Vacuum-sealed storage bags

      • Heat-sealed plastic sheet

    • Nozzle/connection to vacuum

      • Hole punch 

• Designs to investigate:

  • • Grain material

      • Flour

      • Styrofoam

      • Fishing line

    • Layer material

      • High-friction fabric

    • Connection to vacuum/vacuum valve

      • Degassing valves that come with the vacuum storage bags

      • Tubing/valve protruding from the seam of the cast 

    • Sealant for external cast casing

      • RTV

      • Heat-sealed plastic sheet

• Parts acquired:

  • • Flour

    • Silicone sheets (refill)

    • Vacuum pouches

    • Hole punch

    • Heat gun

    • Heat-sealed plastic sheet

    • Tygon tubing

Accomplishments from Previous Week

• Tests conducted:

  • • Strain rate for grain jammer (flour)

    • Strain rate for layer jammer (sandpaper)

• Fabrication 

  • • Grain jammer (flour) 

    • Layer jammer (sandpaper)

• Parts Ordered:

  • • RTV

    • Vacuum space sealer

    • Fishing line

• Logistics

  • • Tool check-off

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

• • test flour (Olesya, Dylan)

  • test flour with fishing line (Olesya, Dylan)

  • test sandpaper (Brian, Kerrianne)

  • test new enclosure option (Olesya, Dylan)

  • test combination of finalized grain and layer option (Brian, Kerrianne)

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

• 1/16/18 - In Person

  • • The reason for using sil-poxy as the adhesive for the silicone sheets was because it does not deteriorate when the cast was bent and flexed

      • If the heat gun does not have enough power, the heat-sealed cast material becomes brittle at the sealed junction and breaks upon deforming. 

    • The layer dimensions are restricted by the surface area (the maximum area of contact) of the Instron plates

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

• 1/11/18 - In Person:

  • • Looked into the suggested alternatives to the nozzle-hex nut connector to prevent leaking and streamline fabrication

      • Ordered vacuum storage bags intended for pillows that included vacuum vent valves

    • Searched for cheap hole punches to determine whether it was worth machining

      • Found and ordered a suitable hole punch

    • Investigated suggested fiber materials available at non-prohibitive quantities

      • Home Depot glass fibers

      • NylonX carbon fibers

      • We decided to begin with fishing line to decide whether we want to spend time pursuing fibers over granular grain materials

    • We have not yet looked into what size vacuum gauge we need

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

• • N/A

Risks and Areas of Concern

• • The Instron plates we have available have a circular surface area of just a few centimeters. This restricts the surface area of our layers and, by extension, the amount of stiffness we can achieve

    • Extending the surface area of the layers outside of the Instron plates would invalidate the ASTM standardized testing

Resources or Information Required but not Available

• • • N/A

Schedule

• • Upcoming milestone: making decision on materials used

Budget (list amount spent and amount remaining)

• Amount remaining $2289.22, $110.78 spent

Progress on Report and Webpage

• The work is split up to complete the report rubrics required and upload them on the webpage by Friday night