engineering design exam prep

  1. design process
    • Not one process, many processes which have common
    • characteristics

    • Start off uncertain, don’t know exactly what final product
    • will look like

    As you continue, final product becomes more and more evident

    • It is good to go outside of comfort zone (e.g. mech. eng.
    • doing chem.)
  2. 8 steps in design process
    • Problem Identification,
    • Idea Generation,
    • Idea Selection,
    • Detailed Design,
    • Design Validation,
    • Implementation,
    • End of Life
  3. RussianDolls:
    • Problems within problems, processes within processes, not evident in the
    • beginning
  4. Problem Identification
    • Make sure you are solving the correct problem, be aware of
    • what you are actually aiming to do

    This allows to find a more efficient solution

    • E.g. Hotel Elevator: Slow elevators, instead of speeding them
    • up they just added mirrors (pass time)

    • junior engineers: … sometimes not your role to change
    • problem?

    Good engineers do start off a little uncertain/confused
  5. Opportunity Identification
    In contrast, not always a problem, sometimes you have an innovative idea (IPAD)

    • After you have identified the problem/opportunity, information gathering is
    • important

    • Figure out what kind of words people in that field use, get
    • to know users, other solutions to the same problem someone else might have,
    • file a patent

    After problem identification, make objectives (long and short term)

    • Scope: How far and deep you plan to go, how much impact will
    • your idea provide

    • Identify what you are NOT going to do, don’t want to solve
    • all problems at the same time

    To do this, you need constraints
  6. Constraints
    Hard Constraints: Legal, by law things you must follow

    • Soft Constraints: Still constraints because you decided you
    • MUST have it

    • They should be well
    • written and should be able to be assessed pass/fail, yes/no

    • ALL constraints must be satisfied for your project to be
    • complete, for your solution to be acceptable

    • Over constrained: Constraints that oppose each other (E.g.
    • building must be taller than 6 feet but shorter than 5 feet)

    • May be less obvious, but basically things that are near
    • impossible to do together
  7. Criteria:
    • similar to constraint, things you want to include in your
    • final solution/product

    • But they are not necessary, and only even think about them
    • if your constraint is met

    • E.g. our car should be fast (criteria), but the priority is
    • for it to even work (constraint)

    Criteria is measured, you want to maximize or minimize it

    • Criteria often controls the decision made, because all
    • solutions are going to satisfy constraints

    • You want a balance among criteria, and remember importance
    • of one criteria vs. another

    • E.g. speed vs. looks, which is more important to you/to the
    • overall goal of the item
  8. Idea Generation
    • This is a very preliminary step, design with an extremely open mind here
    • There is more than one solution to any problem, find them, choose best one
    • Transportation A to B (Many options, walk, run, drive)
    • Communication (Talk, text, email, etc.)
    • Techniques for idea generation, brainstorming
  9. Feasibility
    • First filter stage, first check which ideas even meet the constraints
    • Try and pick best candidates to minimize analysis effort (which requires time + money)
    • *Most innovative ideas usually get lost here, need to use experience and open mindedness to judge
    • Make sure good ideas don’t get thrown out at this stage
    • This is the least depth of analysis, but perhaps most important, most judgement required here
    • After the feasibility you should have a few ideas left
    • One is too few (too many constraints or not enough effort on idea stage)
    • A lot is too much (use another filtration process)
    • 90% decisions, 90% cost quote slide ?
    • Not only decision stages, decisions are happening all the time
  10. Idea Development
    • Consists of 3 main things:
    • Multiple, parallel (happening at same time) activities complimenting each other
    • Analysis of all the parts of the idea, synthesizing and pulling them all together into one solution
    • Virtual and physical prototyping, calculations/computer simulations (solid works) and prototypes, scale models
    • Find things that are right/wrong about the different ideas, further analyze and decide which are best
    • Synthesize, put best ideas into one solution
    • *Challenges: Hard to do an analysis for ALL ideas you initially had, this is why filteration process/feasibility is so important
  11. Preliminary Design
    • Ideas at this point are pretty raw, start putting another layer of effort/detail
    • Main goal here is to decide upon best idea and move forward
    • Very decision driven, try to differentiate one idea from another
    • Performance vs. criteria, may want to start relating back to constraints again
    • enough depth slide??
    • Also figure out budget in a little more detail
    • initial Budget estimation: capital cost (estimate big main parts), operation costs (estimate what it'll take to keep it running), end of life cost (what is going to cost to remove/dispose)
  12. Decision Making/DESIGN VALIDATION (OCCURS SORT OF IN BOTH)
    • Pretty much continuous throughout prelim design and idea development
    • Usually very informal and subjective
    • When making formal/important decisions, you want to be objective, third person point of view
    • Perhaps use decision matrix (use weighted criteria, score out of 10, choose best one statistically)
    • *Make sure weighting isn't subjective (don’t weight speed most because you like speed), look at it all objectively, what is most important to solving solution/problem, remember purpose of object
    • Final decision: Don’t just trust decision matrix, look at results (maybe there are two close solutions)
  13. Detailed Design/ Design Validation
    • At this point you have one idea, but this idea can continue to evolve and grow and be shaped
    • Now you can afford to invest a lot more time and money
    • Work out all of the details (e.g. specifications, exact size, number of nuts and screws, etc)
    • It should theoretically be able to be built at this point
    • This one final chosen design should make complete and total sense with respect to the constraints
    • Its contribution to all the criteria is evident
    • It is the best that it can be, does not have to be perfect obviously
    • LOT S of virtual/physical design effort should be put in at this point
    • Engineering models, 3D sketches, equations of the system/product
    • Create prototypes, full scale if possible, run crash tests, make sure it is user proof
    • "optimization", maximize/minimize what you want
    • heuristic optimization ?
  14. Implementation
    • Manufacturing, make sure it is going to be built how you designed it
    • Process and buildings, be ready for errors and challenges that arise at this point, surprises
    • E.g. There are alpha and beta trials with all software, but bugs and problems persist
    • Recalls are sometimes a solution to this
  15. End of Life
    • Waste, how will you deal with it
    • What are the costs of disposal, what will it cost you, is environment a concern
    • Next version designs, now you see strengths and weaknesses of the product (large scale trial and error)
Author
alazeidan
ID
252414
Card Set
engineering design exam prep
Description
engineering design exam prep
Updated