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Systems Engineering Management. MSE607B Chapter 5 Design Review and Evaluation. Learning Objectives. Explain the basic philosophy of design evolution Describe the evaluation methods Explain the informal and formal design reviews
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Systems EngineeringManagement MSE607BChapter 5Design Review and Evaluation
Learning Objectives • Explain the basic philosophy of design evolution • Describe the evaluation methods • Explain the informal and formal design reviews • Explain the feedback and corrective-action loop associated with these activities
Design Review and Evaluation Requirements • Formal mechanism to ensure design will meet consumer need • Design evolves through iterations from initial definition to firm system configuration • Requirements verification process required from the beginning • Early detection of potential problems allows to incorporate necessary changes easily • An ongoing design review and evaluation effort is required • Overall review process through combination of several approaches: • Informal day-to-day review and evaluation • Formal design reviews at designated stages • Serve as a vehicle for communications • Serve as the formal approval of design data
Informal Day-to-day Review and Evaluation • Performed as design decisions are made and data developed • Informal activity • Results of design reviewed and discussed on a day-by-day basis • Output leads into the formal design reviews • Ensure that the results of design: • Communicated in a clear, effective, and timely manner to all members of the design team • Compatible with initially defined requirements for the system • Review procedure has to be accomplished efficiently and in timely manner
Formal Design Reviews • Conducted at designated stages in the evolution of design • Serve as a vehicle for communications and the formal approval of design data. • Purpose • Review system requirements specification document • Ensure documented design reflect current knowledge of customer and market requirements • Identify areas where design may not be consistent with product development constraints • Put the design document under version control to serve as a stable baseline for continued new product development
Formal Design Reviews (cont.) • Preliminary Design Review (PDR) • Ensure planned technical approach will meet the requirements • Critical Design Review (CDR) • Ensure design implementation has met the requirements • Test Readiness Review (TRR) • Review preparations and readiness for testing, including test procedures • Production Readiness Review (PRR) • Ensure design completely and accurately documented • Ensure design ready for formal release to manufacturing
Conceptual (Preliminary) Design Review • PDR • Usually scheduled toward end of program conceptual design • Deals primarily with top system-level requirements • Results constitute basis for preliminary system design and development activity • Participation include representation from both the consumer and producer organizations • Purpose: • Review and evaluate the functional baseline of the system
Topics Covered in Conceptual Design Review • Objective • Review and evaluate functional baseline of the system • Feasibility analysis • Results of technology assessments and trade-off studies justifying the system design approach being proposed • System operational requirements • System maintenance concept
Topics Covered in Conceptual Design Review (cont.) • Functional analysis • Significant design criteria for the system • Effectiveness of merit and technical performance measures • System specification Type A • System engineering management plan • Test and evaluation master plan • System design documentation
Systems Design Reviews • Usually scheduled during preliminary design phase • Functional requirements & allocations are defined • Preliminary design layouts & specifications are prepared • System-level trade-off studies are conducted • Oriented to the overall system configuration • Ensure that requirements described in the system specifications are maintained as design evolves • Should include representation from • Consumer • Producer • Major suppliers
Topics Covered in Systems Design Reviews • Functional analysis and the allocations of requirements • Development, process, product, and material specifications • Type B, C, D, and E • Design data defining the overall system • Analysis, reports, trade-off studies, and related design documentation. • Assessment of proposed system design configuration in terms of technical performance measures (TPMs) • Individual program/design plans
Equipment/Software Design Reviews • Formal design reviews covering equipment, software, and other components of the system: • Scheduled during the detail design and development phase of the life cycle • Usually oriented to a particular item • Should include representation from • Consumer • Producer • Applicable supplier organizations
Topics Covered in Equipment/Software Design Reviews • Process, product, and material specifications • Types C, D, and E • Design data defining major subsystems, equipment, software, and other elements of the system as applicable • Analyses, reports, predictions, trade-off studies, and other related design documentation • Assessment of the proposed system design configuration in terms of the applicable TPMs • Engineering breadboards, laboratory models, service test models, mock-ups, and prototype models • Supplier data covering specific components of the system
Critical Design Review (CDR) • Generally scheduled after the completion of detail design, but prior to the release for production or construction • Design is essentially “frozen” at this point • Proposed configuration evaluated for adequacy and producibility • Results describe final system/product configuration baseline prior to entering into production or construction. • Constitute the last in series of progressive evaluation efforts • Reflecting design and development from a historical perspective • Showing growth and maturity in design as the engineering project evolved
The Design Change and System Modification Process • Important that any changes to the baseline be tightly controlled • All changes carefully recorded and documented • Configuration identification • Controlling the changes • Maintaining the integrity and continuity of design • Configuration management
The Design Change and System Modification Process (cont.) • Configuration Management (CM) • Identifies the functional and physical characteristics of an item • Controls changes to characteristics • Records and reports change processing and implementation status • Proposed design changes initiated during any phase in the life cycle • Prepared in the form of an Engineering Change Proposal (ECP)
Engineering Change Proposal (ECP) • Each ECP should include: • Statement of the problem and description of proposed change • Description of alternatives considered in responding to the need • Analysis how change will impact system performance • Analysis to ensure proposed solution will not cause a new problem • Preliminary plan for incorporating the change
Engineering Change Proposal (ECP) (cont.) • Description of the resources required to implement the change • Estimate of the costs associated with implementing the change • Impact on the system if the proposed change is NOT implemented • Classified • Class 1 changes • Design changes that will affect fit, form or function • Class 2 changes • Design changes that are relatively minor in nature • Will not affect system specification requirements • May be classified as “emergency”, “urgent,” or “routine”
Summary • Addressed the basic review, evaluation, and feedback process of system design • The process is critical in regard to the objectives of system engineering • Must be tailored to the specific system development effort and must be properly controlled • An ongoing measurement and evaluation activity is essential and must be initiated from the beginning • Without proper controls, the incorporation of design changes ay be costly in terms of possible modifications and system support
Interactive Workshop • Preliminary Design Review (PDR): • Ensures design implementation has met the requirements • Ensures that the planned technical approach will meet the requirements • Review preparations and readiness for testing, including test procedures • Ensures design is ready for formal release to manufacturing
Interactive Workshop • System design reviews ensure that: • Requirements described in the system specifications are maintained as design evolves • Proposed design changes initiated during any phase in the life cycle are documented • Proposed design changes initiated during any phase in the life cycle are documented • Results constitute basis for preliminary system design and development activity • None of the above
Interactive Workshop • Configuration Management (CM) is the process that: • Identifies the functional and physical characteristics of an item • Controls changes to functional and physical design characteristics • Records and reports change processing and implementation status • All of the above
Interactive Workshop • The Critical Design Review, also known as CDR, is generally scheduled: • After the completion of detail design, but prior to the release of firm design data for production • After the completion of detail design and during the release of firm design data for production • During the detail design and development phase of the life cycle • During the requirements definition phase of the life cycle
Interactive Workshop • The purpose of conceptual design review is to: • Experiment with different packaging during formal design • Convey final design approach during design review • Review and evaluate the reliability baseline of the system • Review and evaluate the functional baseline of the system
Homework Assignment • Chapter 5 – Textbook page 246 • Answer questions 1, 4, 7, 11 and 13 • Read Chapter 6 - Engineering Program Planning • Pages 247-333