1 Product Development Process Requirements Definition (Chap. 3) Conceptual Design (Chap. 3 and 4) Detailed Design (Chap. 5) Manufacturing (Chap. 7) Logistics, Supply chain, and Environment (Chap. 8) Test and Evaluation (Chap. 6) Fig A5.1 Product Development Process

Chapter 5: Detailed Design: Analysis and Modeling 5.1 Important Definitions Detailed design is a group of tasks to finalize a product design that meets the requirements and design approach defined earlier. Design analysis is a process of examining (through science and math) how design parameters influence the the performance of the product when it interacts with the environment (human-machine interaction, and environment-machine interaction). 2

5.1 Important Definitions (cont.) Design synthesis is a process of designing (or generating, or creating) a product so as to satisfy a given set of design requirements. Modeling and simulation are tools for evaluating and optimizing designs, services and products. 3

5.2 Design Analyses People of various disciplines must have access to CAD, database and the internet that contain: –CAD drawings and parts, software and material data. –Vendor history and information. –Design rules and lessons learned. –Design and support specifications and guide lines (scenarios, product use profiles, performance, producibility, reliability, supportability, and design to cost). –Detailed producibility data (capabilities of special and standard processes, testability, and estimated production quantity). –Detailed reliability data (reliability models, failure history, physics of failure, failure mode information). –Results from prototyping testing. 4

5.6 Prototypes in Detailed Design Physical models (prototypes) and software models (virtual reality) are used to: –gather information to reduce uncertainty –optimize parameters –test the design 5

5.7 Modeling and Simulation Modeling and simulations are tools for evaluating and optimizing designs, services and products. For a Simulation Tool to be useful and trustable, it must be: –Realistic and correct. –Easy to use. –Well-planned, well-managed, and well-coordinated (planning what to accomplish by simulations, identifying simulation requirements, etc.) –Accepted by users (technical performance of simulations, etc.) –Favorable in benefits-cost ratio. –Modular, flexible, and expandable. –Transportable ( compatible and integrated to new applications and design efforts). 6

5.9 Variability and Uncertainty Design parameters can vary from time to time during product development due to: –Design variability (e.g. precision, interaction between parts) –Manufacturing variability (e.g. tolerance, vendor) –Effects of stress and time (e.g. stress failures, aging) –Uncertainty (e.g. unknown data, incorrect models, unknown product use, part interactions, environment) –User and use variability (e.g. number of customers, skill level) 7

5.15 Failure Mode Analysis A Failure Mode and Effects Analysis (FMEA) is a technique for evaluating and reducing the effects caused by potential failure modes. –The objectives of FMEA are Identifying possible failures. Rating severities of failures. Considering actions to be taken for these failures. –There are several variations of FMEA such as Design FMEA (DFMEA) and Manufacturing FMEA (MFMEA) –See examples of FMEAs (DFMEA and MFMEA) in Fig –There are many on-line references about FMEA such as: tools/overview/fmea.htmlhttp://asq.org/learn-about-quality/process-analysis- tools/overview/fmea.html 8

9

5.15 Failure Mode Analysis (cont.) A Fault Tree Analysis (FTA) develops a model that graphically and logically represents various combinations of possible events (i.e., failures or faults) that could cause or lead to a particular undesired situation. –A fault tree is composed of a top event with the various situations or sub-events that must occur before the top event would occur. 10

5.15 Failure Mode Analysis (cont.) –Logic and event symbols are used to express fault trees. Study the following symbols: For logic gates: OR, AND, and INHIBIT For event symbols: Basic (circle), Undeveloped (diamond), and Intermediate (rectangle) from the web sites below. collections/nuregs/staff/sr0492/sr0492.pdf (See Chapter IV of this document.) collections/nuregs/staff/sr0492/sr0492.pdf (FTA symbols) –See an example of FTA in Fig

12