Principles of Engineering System Design

1. Principles of Engineering System Design Dr T Asokan asok@iitm.ac.in

2. INTRODUCTION TO SYSTEMS DESIGN Physical Architecture Development Dr T Asokan asok@iitm.ac.in

3. Six functions of Design Process • Define System Level Design Problem • 2. Develop the system functional architecture • 3. Develop the system physical architecture 4. Develop the system operational architecture 5. Develop the interface architecture 6. Define the qualification system for the system

4. Case Study: Aircraft crash- Iowa • United 232: 3-engine aircraft crashed on 19/7/1989 while making an emergency landing after losing one of the three engines. 110 people died, 185 survived. • The fan disk of the engine at the fuselage separated from the engine and crashed through the tail. • Two engines were quite sufficient to make a safe landing, but the aircraft stabilization system failed to control the descent rate. • Three redundant hydraulic systems, each powered by a unique engine, were available for aircraft stabilisation.

5. The three hydraulic system converged at the location near the tail where the fan disk ripped out, the single point of failure for all the hydraulic systems. • A pre-existing fracture on the surface of the fan disk was identified as the main cause of engine failure • The design flaw of single point failure resulted in the aircraft crash.

6. Physical Architecture Physical architecture of a system is a hierarchical description of the resources that comprise the system. The hierarchy begins with the system and the system’s top-level components and progresses down to the configuration items (CI). The CIs could be software, hardware, or a combination of hardware and software, people, facilities, documents etc. It provides resources for every function identified in the functional architecture

7. Physical Architecture Development • Generate a generic physical architecture from functional architecture • Create a morphological box for alternative physical elements • Generate alternative instantiated architectures • Select suitable physical architecture • The exit criterion is the provision of a single physical architecture that is satisfactory in terms of detail, quantity, and quality for development

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10. Generic Physical Architecture is a description of the partitioned elements of the physical architecture without any specification of the performance characteristics of the physical resources that comprise each element. It provides common designators for physical resources in a hierarchical decomposition. No specific physical items are identified here. T Asokan ED309

11. SYSTEM FUNCTION m o r e l ev e l 1 f u n c t i o n s Function1 Function2 m o r e l ev e l 2 f u n c . Func 1.1 Funct 1.2 Funct 1.3 Fu n c . 2 . 1 Fu n c . 2 . 1 Fu n c . Fu n c . Fu n c . Fu n c . Fu n c . Fu n c . 1 . 1 . 1 1 . 1 . 2 1 . 1 . 3 1 . 2 . 1 1 . 2 . 2 1 . 3 . 3 L o w e r l ev e l f u n c t i o n s S h o w s t h e f u n c t i o n a n d h i e r a r c h y GENERIC ARCHITECTURE

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19. Fun c t i on s C o m pon e n t s C o m pon e n t s Fun c t i on s f c c f 1 1 1 c 1 f c f 2 2 2 2 c f c f 3 3 3 3 c f c f 4 4 4 4 c f c f 5 5 5 5 O n e - t o - on e a nd on t o Fun c t i on f o r t h e a ll o ca t i o n f un c t i on f o r t h e a ll o ca t i o n o f f un c t i on s t o c o m pon e n t s o f f un c t i on s t o c o m pon e n t s Instantiated Physical Architecture is a generic physical architecture to which complete definitions of the performance characteristics of the physical resources have been added.

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21. MAPPING Instantiated Architecture T Asokan ED309

22. Morphological Box for alternatives A morphological box is a matrix representing the components of the generic architecture and the alternative choices for fulfilling that generic component. Morphological analysis divides a problem into segments and posits several solutions for segment.

23. Morphological box for a hammer T Asokan ED309

24. H a nd l e L e ng t h S t r i k i ng F ea t u r e 1 i n c h 8 i n c h e s g r oo ve d N a il R e m o va l 22 i n c h e s F ea t u r e 1 . 25 i n c h 1 i n c h g r oo ve d f l a t A ng l e d 1 . 25 i n c h f l a t S t r a i gh t 12 O z. W oo d F i b e r g l as s 24 O z. 16 O z. S t ee l S t ee l I - b ea m 20 O z. G r a ph i t e W e i gh t o f H a mm e r H ea d H a nd l e M a t e r i a l

26. There should be at least one column in the morphologic box for each generic component in the generic architecture. • No requirement that each generic component have the same number of columns. • Generating creative alternatives for generic components recommended • In some situations more than one choice could be selected for a single instantiated architecture

27. User I/ O O t h er S ys t e m D i rec t io n Lo ca li z a t io n P r o cess o r In t er f ace s S uppo r t Re gul a r M a p & N on e N on e N on e Ce ll P hon e Da t a b as e M a p, Da t a b ase , V e hi c l e ’ s D i rec t io n S p ec i a l H o r n R ou t in g A lgo r i t h m P r o cess o r S e n s o r Ce ll P hon e 32 - bi t St a ff e d E l ec t r o 4 ” L C D Ligh ts P r o cess o r C on t r ol Ce n t e r G yr o s G PS A u t o ma t e d P o r t a bl e 6 ” L C D Car D oo r T ra n s pond e r C on t r ol Ce n t e r P C ( 486 +) Lo ck s Full G PS 6 ” L CD & E mer g e n c y S uppo r t T ou c h S cree n S ign a l B u tt on & A i r Ba g Key P a n e l Ac u ra Nav ig a t ion S ys t e m Ca dill a c ’ s On s t a r B M W Nav ig a t ion S ys t e m Lin c ol n ’ s R ES C U J o y St i c k Old sm obil e Guid es t a r R E T K I C on t r ol K no b V oi ce Ou t pu t Automobile Navigational Support system

29. manual propulsion system for a small boat.

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32. GRAPHIC REPRESENTATION OF PHYSICAL ARCHITECTURE BLOCK DIAGRAM T Asokan ED309

34. Issues in Physical Architecture Development • Functional Performance • Availability and other “..ilities” as achieved through such characteristics as fault tolerance • Growth Potential and adaptability • Cost