2: Engineering Design Process Flashcards
What is Engineering Design?
Engineering design is the structured and systematic process through which engineering knowledge and skills are applied to solve REAL-WORLD, OPEN-ENDED
What is the novice approach to design? what are the issues with this approach?
novice approach: not systematic and involves trial and error strategy
Result is rarely optimized, rarely the most efficient in terms of time, money, and resources
What is conceptual design? why is it important?
Conceptual Design is an early step in the engineering design process.
- It is important as one mistake can make the project impossible or very expensive
Side Note: All help provided by CAD is at DETAILED DESIGN, not this stage (conceptual design looks over the problem more generally, multi-disciplinary, more robust/changing, etc.)
What are some common features / important characteristics found in all engineering design processes?
Features:
- each model presents the design process as a sequence of stages/steps
- there is a preferred order in which we do things in design
Characteristics:
- A clear understanding of your design goal is critical
- model illustrates a iterative process
What are the 5 (or 6/7) stages of our design process model?
- Obtain a problem
- Study and clarify the problem
- generate potential solutions
- identify the most promising solution
- develop and test solutions
- implement solutions
x. ITERATION (review and revise solutions)
Elaborate on stage 1 of the design process
stage 1: study and clarify the problem
goal: create a precise definition of the problem by establishing:
- What are we trying to accomplish
- Who are we doing it for (needs/wants)
- Constraints?
- Needed information?
Answering these questions determine our design specifications
Elaborate on stage 4 of the design process
stage 4: develop and test solution
The solution from stage 3 is further analyzed, refined, and studied,
prototyping, experimentation, simulations, and stakeholder consultation are all used to improve and finalize the design
ITERATION PLAYS A SIGNIFICANT ROLE!
Elaborate on stage 2 of the design process
stage 2: generate potential solutions
- process of identifying and documenting as many potential solutions as possible
Elaborate on stage 5 of the design process
stage 5: implement solution
this includes our final construction and delivery of our solution
documentation of the project is needed
real-world projects may have on-going work:
- operation
- maintenance
- upgrades
- recycling
Elaborate on stage 3 of the design process
stage 3: identify the most promising solution
we reduce the solution space to a single solution through 3 main steps:
- screening
- ranking
- scoring
design specifications from stage 1 will be used to justify our decision
Elaborate on stage x of the design process
iteration
iteration happens between any 2 stages in our design model
the design process is never achieved with a single pass through as new information, issues, and ideas come to light as we engage with the process!
Why do we use the engineering design process?
Compared to the novice approach of engineering, THE FOLLOWING INCREASE:
- the quality of the final solution
- the chance of completing the project on time
- the change of completing the project on budget
elaborate on costs associated with the design process: What 2 types of costs are considered?
actual costs:
- the money, effort, and resources we spend or consume in a project at any point
costs committed:
- the actual cost to date PLUS the anticipated future costs for decision we MADE
if you were to graph the actual costs curve vs the costs committed curve, what would the graph look like?
The actual costs curve would be exponential:
- low at the start, jumps up exponentially at end
the committed costs curve would be logarithmic:
- jumps up quickly at start and levels out until the end
After graphing the actual costs vs costs committed diagram, what are the main takeaways?
INFO:
- the early stages of the design process are cheaper than later stages
- it costs less to make changes early compared to later!
- the decisions we make early determine most of the spending that comes later
TAKEAWAYS:
- The costs committed curve tells us the cost to address a major mistake made at any given time BUT THAT GOES UNDETECTED UNTIL LATE IN THE PROJECT
- the difference between the costs committed and actual costs curve at any point represent future costs we still have some ability to change!
What is a stakeholder?
stakeholder: an individual, group, or organization influenced by a project, or has influence on a project
How we categorize and prioritize stakeholders?
We use the Stakeholder Salience Model
stakeholders are categorized into 3 dimensions:
- power (a stakeholder’s ability to influence a project)
- legitimacy (a stakeholder’s moral or legal right to have a say in the project)
- urgency (describes how time sensitive a stakeholder perceives their needs)
We rank each stakeholder based on the number of salience dimensions
1: stakeholder has one dimension
2: stakeholder has two dimensions
3: stakeholder has all dimensions
Notes:
- salience is often dynamic, with groups increasing or decreasing in salience as the project goes on
- being thorough in this step is critical to a successful project
What can you do after utilizing the stakeholder salience model?
We can use the salience model to develop a stakeholder engagement plan
Ex/
A table with strategies and on the right, we choose whether to use the strategy or not based on how many salience dimensions each stakeholder has
What is the project management institute (PMI)?
It is simply another model we can use to categorize and prioritize stakeholders.
y-axis: impact (ability to influence)
x-axis: interest in the project
divide into 4 groups based on above:
- manage closely (high impact, high interest)
- keep satisfied (high impact, low interest)
- keep informed (low impact, high interest)
- monitor (low impact, low interest)
What are stakeholder needs? What are the three types?
needs: captures the wants and wishes of the stakeholders and the things that will increase/decrease stakeholder satisfaction
expressed needs: needs the stakeholders are aware of and freely share
latent needs: needs that would please stakeholders but they might not be aware of
threshold needs: needs stakeholders expect but might not think to mention
What are requirements?
Requirements:
minimal threshold our design must achieve and the qualities or features it must have (or not have) in order to be considered acceptable by stakeholders
What are evaluation criteria? What is stakeholders satisfaction?
Evaluation critera:
Attributes of importance to stakeholders that determine satisfaction
0%: corresponds to a solution that just barely meets a requirement
100%: corresponds to a solution where further improvement do not increase desirability of a solution
How do we check evaluation criteria and their corresponding stakeholder satisfaction?
We choose an evaluation criteria and create a satisfaction plot
Ex/
y-axis: satisfaction %
x-axis: cost ($)
starts initially at 0-200$ where satisfaction stays at 100%
Could go down after than and hit 0% at, say, 400$
What is validation and verification?
Validation and verification are ways to check our work at each step:
validation: asks “have we accurately translated stakeholder needs to target design specifications?”
- happens in stage 1, may happen later too
Verification: asks “does our chosen design solution meet all requirements and maximize stakeholders satisfaction?”
- happens in later stages once we have a solution
What should we be focusing on / not focusing on in stage 2 of our design process?
- Focus on quantity, not quality
- don’t fixate or anchor on one single idea. variety is the key to success
- set aside the target design specifications from stage 1
- don’t discourage wild ideas
- don’t judge ideas (yet)
What are 4 methods we can use to generate as many ideas as possible?
Brainstorming:
- write down ideas, draw, make sure everyone has a change to contribute
Gallery method:
- team members work individually to create ideas
- ideas are assembled and reviewed by team
- iterative process where new ideas can be generated or old ideas and be modified, combined, or improved
C-sketch:
- team members sketch for a set amount of time then pass sketches to their right
- add or subtract from the sketch you recieve
- no words or descriptions, just pictures
Inverse and Extreme:
- A round of concept generation focusing on solving the inverse, or opposite problem
- Try to think of the most extreme solutions for each design requirement
Elaborate on screening:
- the process of removing ideas that can never work BASED ON REQUIREMENTS!
- iteration should be used to save screened ideas if possible
elaborate on ranking:
- a strategy to reduce the number of ideas to score
- less time consuming than scoring & BASE ON EVALUATION CRITERIA!
- goal is to identify the ideas with the most potential to maximize stakeholders satisfaction
- any concept that is about to be eliminated should be reworked (if needed)
- the number of solutions to be advanced is a balance on resources available for scoring and the need to ensure the best idea is included
What are the three main ranking systems we spoke about?
Methods include:
- individual voting: each person gets a limited number of votes to vote for their favorite ideas that passed screening
Pairwise Comparison:
- compare each idea against every other concept one by one
- 1 point for each winner, half points for ties
criterion-based ranking:
- evaluate each criteria for each concept
- give a +, -, or 0 depending on anticipated performance
elaborate on Scoring:
- quantitative
- time consuming
- goal is to max stakeholder satisfaction
Main tool: Weight Design Matrix (WDM)
- write a list of criteria
- assign a weight to each criteria (depends on how important a criteria is to stakeholders)
- score each idea on each criteria
Multiply scores by weights and tally the results
Note: Also remember to conduct a sensitivity analysis and interpret results carefully. Satisfaction curves can be used to help score as well!
When can a stage be bypassed in part 3 of our design process?
A stage can be bypassed in stage 3: identifying the most promising solution when…
- small number of concepts remaining after screening (no ranking)
- ranking generating a decisive leader (no scoring)
Additionally multiple ideas can be carried through stage 3 to stage 4: Develop/testing
(usually one safe idea and one ambitious idea
