Concept Generation The Design Process Objective Trees Concepting Evaluating Alternatives MAE 156A

2 Qualities of a Successful Designer Clarified requirements - asked questions which focused on the problem structure Actively searched for information and critically checked given requirements Summarised and prioritized design requirements Did not suppress first solution ideas, but did not fixate on them either - detached personal biases and preferences from the conceptual design stages Recognize that sometimes the best solution may not be yours! Produced design alternatives - but continuously assessed and evaluated them to limit the total number under consideration

MAE 156A 3 Modeling the Design Process Descriptive models of the design process usually identify the significance of generating a solution concept early in the process. Prescriptive models emphasize the need for more analytical work to precede the generation of solution concepts. Analysis: listing of all design requirements and reducing these to a complete set of logically related performance specifications Synthesis: finding possible solutions for each individual performance specification and building up complete designs with least possible compromise Evaluation: evaluating how well alternative designs met performance requirements Communication: prepare manufacturing documentation

MAE 156A 4 Objective Trees The starting point for a design is often an ill-defined problem, or a rather vague requirement. So the first step in design is to clarify objectives using, for example, an objective tree. Prepare a list of design objectives from the design brief, from questions to the client, and from discussions within the design team. Order the list into sets of higher-level and lower-level objectives. Draw a diagrammatic tree of objectives, showing hierarchical relationships and interconnections. The branches (or roots) in the tree represent relationships which suggest means of achieving objectives. Robust Convenie nt Easy to install Not affected by thermal expansion Reliable In-line design Modular construction High-Pressure Pump (ref Cross)

MAE 156A 5 Possible Objectives for Concepting Product Development Find a fundamental solution to a design problem; used as the basis for go-ahead decision Innovation Develop new solutions that promise to transform a product or industry Shared Vision Use concepts to create a corporate-wide vision for future products Competence Challenge one's own expertise Expectation Management Prepare consumers for new products by showcasing them in public before they are ready

MAE 156A 6 Concept Generation Use morphological sketches to describe different means for achieving the functional requirements of the design. Cross, N., Engineering Design Methods, Wiley 2000.

MAE 156A 7 Decision Matrix Discrete variables are usually considered using a decision (or Pugh) matrix. WeightA (ref)BCD E Portability Ease of Maintenance Ease of Use Noise Market Appeal Total Total Weighted Total Rank Summar y Alternatives Attributes

MAE 156A 8 Limitations of the Decision Matrix It is often very difficult to produce quantitative information suitable for matrix methods. It is often difficult to quantify market potential and appeal. Matrix methods may often produce only an average solution, because the possible benefits of a unique solution are hidden by the risks. Decision-making rationale forces only one solution. A carefully planned evaluation based on a scoring model may require a relatively comprehensive investigative and measuring phase.

MAE 156A 9 DFA/DFM and Cost Reduction Guidelines Can any function, and therefore its components, be eliminated altogether? Are any components redundant? Can the number of components be reduced? Can several components be combined into one? Is there a simpler alternative? Is there an easier assembly sequence? Is there a simpler shape? Is there a satisfactory cheaper material? Can the method of manufacture be improved? Can parts be standards rather than specials? Can dimensions be standardized or modularized? Can components be duplicated?

MAE 156A 10 Design Process Summary Step 1. Recognition Write a design brief or proposal Step 2. Preparation Background research, analysis, and information search Build an objectives tree and perform functional analysis Step 3. Incubation Take a holiday (and try to talk the company into paying for it) Talk the problem over with colleagues Tackle another problem Step 4. Illumination Brainstorm using morphological sketches and charts Enlarge the search space with random alternatives Step 5. Verification Check that performance specifications and design objectives are met

MAE 156A 11 Product Development in Uncertain Conditions Darwinian Selection Company launches multiple new product offerings simultaneously to see which has the greatest market appeal Product Morphing Initial product features evolve as consumers adopt and adapt the new products Vicarious Experiments Companies learn from competitors and from their potential customers; the best elements are then incorporated into their own new offerings. Variants Strategy New variants use parts of the first product, but new technologies, new designs and/or new features are introduced Accessory Method Company markets an interface that links the new offering to something that has already been widely adopted

MAE 156A 12 Further Reading Cross, N., Engineering Design Methods: Strategies for Product Design, Wiley Keinonen, T. and Takala, R. (eds), Product Concept Design: A Review of the Conceptual Design of Products in Industry, Springer