Week 10 April 15th Scribe Notes

Updates
  • Guest speaker Bill Becker will present on wheels on Monday, April 20th
  • Wednesday, April 22nd we will “Show and Tell” home projects
  • Fusion360: work on drawing motorcycle parts for final project
Today: Guest Lecture by Professor Arnold on Material Science

Professor Arnold spoke to us about the application of materials in context and the importance of carefully thinking about the materials of individual parts.

  • Carburetor
      • The goal of a carburetor is to bring together materials that are highly reactive (oxygen and fuel), therefore the material of the carburetor must be able to withstand corrosion.
      • Made of aluminum and brass
      • Materials change over time, so using two different materials has its advantages in acting as a preventative measure against corrosion.
  • Frame
      • Braise vs Weld
          • braising: uses multiple kinds of materials; only on surface of material
          • welding: melting metals together; penetrates into the material
      • Why use a hollow tube for the frame rather than a solid or alternative shape?
          • the tube has the same necessary mechanical properties, and reduces weight and cost
  • Brakes
      • want a material for the brake pads that provides lots of friction, but won’t melt
      • solution: composite of ceramics and metals
          • ceramics provide the heat resistance but are brittle
          • metals provide the ductility
      • Example of carbon brake pad material:
          • Phenol resin (thermoset polymer), steel (ductility & even heat distribution), graphite (carbon-high temperature material), cashew (organic material-carbon)
  • Polymers
      • molecule (monomer) that repeats lots of times
      • properties can range from soft and squishy to hard and brittle
  • Epoxy
      • polymers that are very hard
      • thermoset polymer (when it reaches high temperatures it will not melt but will turn into a vapor)
      • In practice, two components are mixed together to form the epoxy. This is an exothermic process that forms a crosslink between the molecules.
  • Forged vs Drop Forged
      • changing a metals shape (by hitting, stretching, etc.) makes it harder, but the trade off is that it becomes more brittle
Chapter 4 Discussion
  • Discussion leader: Jen
  • Motorcycle references on pgs. 88, 89, and 94
      • Pneumatic die grinder-air tools; gentle & high speed; commonly used for m/c
      • crank 69mm stroke; pistons to fit an 87mm bore; double-barrel carburetor; free-flow exhaust (less back pressure & higher power); centrifugal advanced distributor; remote oil cooler and full-flow filter; lightened flywheel; heavy clutch (heavier clutch = tighter spring = harder push on clutch)
  • Plywood vs solid wood (in reference to rosewood plywood)
      • Rupert: rosewood plywood is plywood with a rosewood veneer on top
      • plywood is not as sensitive to humidity changes as solid wood is
  • Cecilia: connection to Zen and the Art of Motorcycle Maintenance; understanding the history of the machine through its physical alterations
  • Careful vs Commanding
      • idea presented by book: figuring out where you fit within these two categories and choosing a profession that matches those tendencies
  • Anna: discussion of Aristotle’s definitions of art-those that “reliably attain their object”(like building) and those that are “stochastic” (medicine) (pg81)
  • Betty Edwards and Drawing on the Right Side of the Brain