Design Concerns

IN DEVELOPING DESIGN CONCERNS THE FOLLOWING PRODUCT ATTRIBUTES/FEATURES SHOULD BE CONSIDERED Physical Structural Environmental Human engineering Life cycle Cost

PHYSICAL Configuration/size Weight Mass properties Dimensions (can bound if unable to define exactly - not less than/not greater than) Tolerances Surface finishes Weight Mass properties Center of gravity Moments of inertia

STRUCTURAL Need to consider piece parts and assemblies (joining mechanisms) Strength Stiffness Impact Durability (fatigue)

ENVIRONMENTAL In-service conditions Temperature, humidity, UV exposure, chemical exposure

HUMAN ENGINEERING Safety Ergonomics Aesthetics

LIFE CYCLE "Cradle-to-grave“ Sustainability, “Green” Warranty Maintenance, repairability Renewable materials Disposal (recyclable, biodegradable, hazardous materials) Warranty

COST Cost (materials, manufacturing process - labor, tooling, equipment usage) Price (look at competing products to gain insight) Profit

ASSUME THE NEED IS A COMMUTER BICYCLE Translating customer input into quantifiable design concerns Physical - lightweight Structural - adequate strength Environmental - will not degrade when exposed to water Human engineering - accessibility to controls Life cycle - easy to service Cost - affordable price

DETERMINING ASSESSMENT MEASURES FOR EACH DESIGN CONCERN Definition: what will be measured to determine how the design performs with respect to the specific design concern (note units) Requirement: if the design concern is a requirement, what is the level (value) of the assessment measure which has to be achieved in order to comply with the requirement (for a design concept to be considered a possible solution) Goal: if the design concern is a goal, what is the desired direction of the assessment measure in order to come closer to achieving the goal (the design concept which performs most favorably with respect to the goals is the best solution) For the bicycle example