Engineering Design GE121 Finding Answers to the Problem Part III / IV Lecture 12A

Limiting Design Space to a Usable Size Pragmatic (practical) issues related to how an artifact will be used, and how it will be made Provides ‘guideposts’ for development of the search space – may narrow rather than expand the search space Design alternatives must be functions of User Needs Available Technologies External Constraints (and some common sense!)

Limiting Design Space to a Usable Size (Continued) Example – Design of vehicles for a campus transportation system Candidate Vehicles Simple bikes High Tech bikes Recumbent bikes Tricycles Rickshaws User Needs may dictate consideration of: Parking availability Carrying Packages Access for Handicapped

Limiting Design Space to a Usable Size (Continued) Available Technologies may affect design alternatives: Materials (affects appearance, manufacturing, price) External Constraints may limit design alternatives: Team’s area of expertise (may be expert in tricycle design) Available Manufacturing Facilities (may dictate material) Practical Considerations – Common Sense! Invoke and apply constraints (similar to user needs, as above) Freeze the number of attributes (avoid those unlikely to seriously affect design – i.e. color) Impose some order on the list (which functions / features are most important) Get Real! (watch out when silly / infeasible options are repeated too often)

Morphological Charts: Organizing Functions and Means to Generate Designs that Work Morphological Charts - Important Alternative Development tools Chart or Matrix Functions or Key Features are listed in the first column Alternate Means of achieving each function are given in that function’s row Generating the Means for each function can be a highly creative process Means do not have to be Words – some designers use sketches or thumbnails to show some alternative means

Morphological Charts (continued) The Morphological Chart can be used to generate Complete Alternatives Leftmost column lists ALL functions Selecting a means from EACH row guarantees that the solution satisfies all required functionality Will NOT, however, guarantee that Alternatives will WORK Or even be internally consistent (see Fig. 5.2b) Judgement is still required This approach can result in a HUGE number of alternatives The morph chart in Fig 5.2 can be used as an example of internal consistency and judgement. If “glass” is the selected material, then “box” and “bag” aren’t consistent containers. If “bottle” is the container, then “waxed cardboard” and “lined cardboard” are not good choices for material.

Morphological Charts (continued) Start with Functions Contain Beverage Material for Beverage Container Provide Access to Juice Display Product Information Sequence Manufacture of Juice and Container

Morphological Charts (continued) Add Means for Each Function Contain Beverage: Can, Bottle, Bag, Box Material for Beverage Container: Aluminum, Plastic, Glass, Waxed Cardboard, Lined Cardboard, Mylar Films Provide Access to Juice: Pull-Tab, Inserted Straw, Twist-Top, Tear Corner, Unfold Container, Zipper Display Product Information: Shape of Container, Labels, Color of Material Sequence of Manufacture: Concurrent , Serial

Morphological Charts (continued) Create Morph Chart (words) Work through this example on inconsistencies such as “glass-bag” or judgements such as “bottle-waxed cardboard”. There are obvious combinations that can be eliminated: such as “can-tear corner” and “bottle-unfold container”. However, thinking about unlikely combinations may spark creative ideas. An implicit assumption in this chart is that the whole container must be made out of the same material (except for the mechanism for opening). Frozen juice concentrates have lined cardboard sides and metal lids. Is that (or another combination) feasible here? Fig. 5.1 p104 Or – Use Thumbnails (next page)

Fig. 5.3 p106

Morph Chart Generating a Complete Alternative Morph Chart showing one means for each function which can be combined to form one complete alternative that looks feasible Fig. 5a

Morph Chart Complete Does not Mean Feasible Morph Chart showing a complete alternative that is not consistent – Glass Bottle with a zipper (zip-lok requires plastic) Fig. 5b

Managing Your Group You may want to consider appointing someone to fill each of the following roles: Project leader Scribe/recorder Project file keeper Report co-ordinator

C-Sketch Method It may be helpful to use the C-Sketch Method to generate ideas from your Morph Chart (examples from microlaryngeal stabilization device)

Activity Create a Morph Chart for your project Start with a List of functions Brainstorm a List of Means for each Function Be Creative in your Brainstorming!