Engineering of Systems Systems Engineering An Introduction M
































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Engineering of Systems

Systems Engineering An Introduction M R Shankar

Outline What is “SE”? n Why “SE”? n Where it can be? n n How “SE”? (A big question) n A Generic SE process

What is a ‘System’? s c i n Avio Me l a c i chan Ele ctri Hy dra cal ulic s

What is a ‘System’? n A group of components that work together for a specified purpose • Components - products (hardware, software, firmware), processes, people, information, techniques, facilities, services and other support elements • Together – integration of many • Purpose – is achieved by implementing many functions

Other Systems Natural Man made Technical Aircraft Missile … Non – Technical Economic system Societal systems … Emphasis on Technical systems

Technical Systems n n n Human-made artifacts Result of engineering activities with the processes of engineering design Difficult to classify systems based on technology like electrical system, mechanical system • Most present day systems are hybrids of simple systems of the past n An indication of the need to use interdisciplinary approach

What is “Engineering”? n Knowledge of mathematical and natural sciences applied to utilize limited resources economically for the benefit of people • Scientific approach • Optimize resources • User/customer in focus Classical Engineering focused mainly on product design

Systems Engineering (SE) n SE is an interdisciplinary approach and means to enable realization of successful systems • It is very quantitative including tradeoff, optimization, selection and integration of products from various engineering disciplines • It is more of an engineering discipline.

Why “SE” is needed Complexity Technical Project

Why “SE”? Wright Brothers Designed, Built and Flew the world’s first powered, controlled, heavier-than-air flight

Why “SE”? ONE Chief Designer – TOTAL knowledge

n n n High Complexity Multidisciplinary Cost & Time “SE” is needed due to Technical complexity

Why “SE”? % 100 Commitment to technology, configuration, cost etc 75 Cost incurred System specific knowledge 50 25 Ease of change Detail design & Concept & prelim. design development Production Use, phase-out disposal

Why SE (cont. . ) n n More systematic way of development Better control of System Development incl. management of risk, changes, configuration Traceability at all levels Operational & supportability aspects Effectiveness Analysis n Risk management n Operational - Maintainability, Availability, Safety etc n Ensures FINAL PRODUCT Fully Meets All User Requirements

Where “SE”? n All levels n Organization level – for a project • Full fledged SE n Subsystem level • We aim at this level!! n Individual level • Systems thinking

Systems Engineering (SE) n Emphasis on • Top-down approach • Interdisciplinary approach • Effort on more complete definition of system requirements • Life cycle engineering approach

Emphasis in SE n Top-down approach • Look at system from top • Decide inputs/outputs taking into account the supersystem • Decide subsystems … down to lower levels n Interdisciplinary approach • Analytical approach is inadequate • Capture the interactions between disciplines • Exploit the synergism of these interactions

Emphasis in SE n More complete definition of needs • Complete definition of needs facilitates verification of system performance • Minimize surprises at later stages n Life cycle engineering approach • Initial approach was Design cycle • Later with Design for Manufacture (DFM) approach Manufacturing cycle also included • Present thinking is to consider three life cycles i. e. Design, Manufacturing and Supportability concurrently • Leading to Concurrent Engineering (CE)

Life-cycle engineering approach Utilization phase Design NEED Development phase Manufacture Deployment Conceptual & Preliminary Design Detail Design & Development Manufacturing Configuration Design Production and/or Construction Product use Phase out and Disposal Manufacturing Operations Product support configuration design and development Product support and maintenance

Product life cycle Identification of need Research Input Conceptual design System concept Preliminary Design Subsystem design Detailed Design & Development Component design Production/Construction Utilization & Support Phase-out and Disposal Development phasing

Systems Engineering process Basic steps n n n n Define system objectives (user’s needs) Establish performance requirements (requirements analysis) Establish functionality (functional analysis) Evolve design and operation concepts (design synthesis) Select a baseline (thro’ trade-off studies) Verify the baseline meets requirements Iterate the process through lower level trades (decomposition)

INPUT Requirements analysis R V Functional analysis D Design Synthesis System Analysis & Control OUTPUT Concept studies System studies Prelim. Design Detailed Design

Requirement analysis Functional analysis Design Synthesis System analysis and control System Engineering process Conceptual design Preliminary design Detailed design & Development phasing System Engineering Management Life cycle approach Developmen t Production Deployment Operation Support Training Verification Disposal This interaction shows how to apply SE process to develop systems in life cycle approach

Aids to SE Management Functional baseline Allocated baseline (‘Design to’ specs. ) Product baseline (‘Build to’ specs. ) Drawing inputs from all the life cycle activities for various development phases Development phasing Baselines System Engineering process System Engineering Management Integrated approach Lifecycle planning Life cycle approach Integrated team from Systems engineering and discipline specialists

SE process overview

SE process mapped to Life cycle

What we have seen What is a System n What is Systems Engineering n Why Systems Engineering is needed? n Life cycle engineering approach leading to Concurrent Engineering n Product cycle & development phasing n Steps in System engineering process n

I will stop here… We will move forward… Ref: INCOSE SE handbook DSMC – SE mgmt guide Systems Engineering & Analysis – Blanchard & Fabrycky

Baselines n Functional baseline : n n n Allocated baseline : n n Top level (system) functions, performance & interfaces. System level technical description System requirements flowed down to items below Item performance specification, interface definitions, process description and drawings ‘Design to’ specifications Product baseline : n n Defining system from top to bottom in terms of physical entities ‘Build to’ specifications

System classification n Natural & manmade systems n n Physical & conceptual systems n n Airline system, economic system Open & closed systems n n River system, Bridges Chemical equilibrium in closed vessel, business organization Static & Dynamic systems n Bridge, Aircraft

What is a system? n A group of components that work together for a specified purpose e. g. Aircraft • Purpose is achieved by implementing many functions • System is made up of components, attributes and relationships • Components are the operating parts consisting of input, process and output e. g. Wing • Components may be structural, flow or operating • Attributes are the properties that characterize the system e. g. Lift generated • Relationships are links between components and attributes • The purposeful action by system is its function.