Fuel Cell Systems Engineering

Transcription

1 Fuel Cell Systems Engineering Lecture 9 Specifications

2 Lecture 9 Topics What is a specification? Specification types Specifications during life cycle Technical Data Package (TDP) Group activities

3 What is a Specification? A document that contains requirements for a specific product or process. Requirements are necessary characteristics for a process or product. A developmental specification thus provides definition of the design challenge. Specifications may include requirements for design, fabrication, assembly, manufacture, procurement, etc. Synthesis is the design solution to the problem defined by the specification.

4 Specification Types System specifications ( A spec) Development specification ( B spec) Product specification ( C Spec) Process specification ( D Spec) Material specification ( E Spec)

5 The System A Specification System description Major system characteristics Related technical performance measures for evaluation General criteria for design and assembly Major data requirements Logistics and producibility considerations Test and evaluation requirements Quality assurance provisions

6 The System B Design or Developmental Specification Results from trade-off analyses and the selection of the best technical approach Includes performance requirements that drive the system design Requirements are allocated to the subsystem level

7 System C Product, or Procurement Specification May be oriented toward fabrication of the item OR procurement of the item. Contains: Complete performance requirements Detailed description of system and components Drawings, schematics, BOM, part or item # Interface requirements Interoperability requirements Environmental requirements Quality assurance provisions Test and evaluation provisions

8 System D Process Specifications Typically applies to fabricated or manufactured items requiring specific techniques to insure essential material properties Example processes include: Heat treatment Plating or coating Welding Marking Preservation and packaging Magnaflux

9 System E Material Specification Applies to raw materials used to fabricate system components Chemical compounds Mixtures Metals, minerals Semi-fabricated materials (wiring, tubing) Structural shapes

10 System Life Cycle Systems Engineering Stages Concept Development Engineering Development Post Development Needs Analysis Concept Exploration Concept Definition Advanced Development Engineering Design Integration & Evaluation Production Operation & Support Retirement Systems Engineering Phases

11 SE Process- The 50,000ft View Process Inputs Requirements Analysis Design Validation Functional Definition Process Outputs Physical Definition Although the specific activities may change slightly depending on the particular system and developmental stage, the general process is similar.

12 The Evolution of Specifications User Requirements Concept Development Engineering Development Production & Deployment System A Spec System B Development or Design Spec Product C or Build To Specs D Process Spec E Material Spec Technical Data Package (TDP) Drawings & BOM Schematics S/w code & flow charts Technical manuals Mfg. part programs V&V provisions Spares provisioning lists Specifications (above)

13 Additional Resources Grady, J.O., System Requirements Analysis, Academic Press, Hunger, J.W., Engineering the System Solution: A Practical Guide to Developing Systems, Prentice Hall, 1995.