Perspectives of enhanced survivability on AES

1. Perspectives of enhanced survivability on AES I.K. Hatzilau, I.K. Gyparis, J. Prousalidis, S. Perros, A.Dalakos Perspectives of enhanced survivability on AES I.K. Hatzilau,Prof. Dr.-Ing, Hellenic Naval Academy (HNA) Lt Cdr I.K. Gyparis,MSc MESE, Hellenic Navy J. Prousalidis,Lecturer, School of Naval and Marine Engineering, National TechnicalUniversity of Athens (NTUA), Greece Cdr S. Perros,MSc Electrical Eng., Hellenic Navy Lt Cdr A. Dalakos,MSc Mechanical Eng., Hellenic Navy 1

2. Perspectives of enhanced survivability on AES I.K. Hatzilau, I.K. Gyparis, J. Prousalidis, S. Perros, A.Dalakos Paper Scope • The paper • Initially, introduces and outlinesmethodologies for the analysis of the survivability concept, for a quantitative assessment • discusses the contribution of propulsion and electric power • systems to the survivability of a ship and • concludes with the analysis of some of the main characteristics • of an AESsystem, which play significant role for the survivability. • * AES survivability issues are been studied for about ten years now. • Some of the most typical papers , of related international conferences • (like ICSS and AES) , are listed in the bibliography of the paper [2-16]. Presented by I.K. Hatzilau 2

3. Perspectives of enhanced survivability on AES I.K. Hatzilau, I.K. Gyparis, J. Prousalidis, S. Perros, A.Dalakos A. INTRODUCTION The interest of ship designers in full electric propulsion systems and AES has been raised, because of :- Recent strict requirements , -Maturing of enabling technologies and- Claimed advantages . Moreover and because of its advantages, AES incorporates the potential for  increased survivability. Presented by I.K. Hatzilau 3

4. Perspectives of enhanced survivability on AES I.K. Hatzilau, I.K. Gyparis, J. Prousalidis, S. Perros, A.Dalakos A. INTRODUCTION Thesurvivability of a shipis defined as “the Capability to avoid and/or withstand a hostile environment”and in a broader sense ‘‘ the capability to fulfil missions overcoming difficulties ’’ Presented by I.K. Hatzilau 4

5. Perspectives of enhanced survivability on AES I.K. Hatzilau, I.K. Gyparis, J. Prousalidis, S. Perros, A.Dalakos B. SHIP SURVIVABILITY Survivability or the ‘survival state’ of a ship is approached under three ‘points of view’ : -by being analyzed [1] --in component–systems states , [2] --in stages evolving in time and -by being connected [3] -- with the amount of after-hit power left available and how this power is distributed between propulsion and non-propulsion load. Presented by I.K. Hatzilau 5

6. Perspectives of enhanced survivability on AES I.K. Hatzilau, I.K. Gyparis, J. Prousalidis, S. Perros, A.Dalakos B. SHIP SURVIVABILITY B.1. Survival state - Component systems analysis- The(after hit-)‘survival state’can be analyzed into ‘component systems states’, as a first step to asses survivability quantitatively, as depicted in the block-diagram. Presented by I.K. Hatzilau 6

7. Perspectives of enhanced survivability on AES I.K. Hatzilau, I.K. Gyparis, J. Prousalidis, S. Perros, A.Dalakos B. SHIP SURVIVABILITY B.1. Survival state-Component systems analysis The next step is expressing component systems survival states as vectors. ------------------------------------Structural integrity has two major components :the longitudinal and the below / above waterline integrity Presented by I.K. Hatzilau 7

8. Perspectives of enhanced survivability on AES I.K. Hatzilau, I.K. Gyparis, J. Prousalidis, S. Perros, A.Dalakos B. SHIP SURVIVABILITY B.1. Survival state-Component systems analysis Battle systems can be analyzed as offensive and defensive.( each of those can be further analyzed to Anti Air Warfare (AAW),AntiSubmarine Warfare (ASW) and Anti Surface Warfare (ASuW)) Presented by I.K. Hatzilau 8

9. Perspectives of enhanced survivability on AES I.K. Hatzilau, I.K. Gyparis, J. Prousalidis, S. Perros, A.Dalakos B. SHIP SURVIVABILITY B.1. Survival state-Component systems analysis Movement is composed by direction and speed. Presented by I.K. Hatzilau 9

10. Perspectives of enhanced survivability on AES I.K. Hatzilau, I.K. Gyparis, J. Prousalidis, S. Perros, A.Dalakos B. SHIP SURVIVABILITY B.1. Survival state-Component systems analysis When all resources are available, we have the Maximum Survival State (1,1,1) Presented by I.K. Hatzilau 10

11. Perspectives of enhanced survivability on AES I.K. Hatzilau, I.K. Gyparis, J. Prousalidis, S. Perros, A.Dalakos B. SHIP SURVIVABILITY B.2. Survival state - Stages analysis Survivability, as examined under a time dependent analysis, is constituted from three major stages, which are involved in degradation of mission capability : 1. Susceptibility(i.e. the inability to avoid a hit) 2. Vulnerability(i.e. the inability to withstand a hit) and 3. Recoverability(i.e. the ability to perform restoration of capabilities, that existed before the hit) Presented by I.K. Hatzilau 11

12. Perspectives of enhanced survivability on AES I.K. Hatzilau, I.K. Gyparis, J. Prousalidis, S. Perros, A.Dalakos B. SHIP SURVIVABILITY B.2. Survival state - Stages analysis Mission Capability of a ship in a hostile environment is shown in the figure, as a function of time. Presented by I.K. Hatzilau 12

13. Perspectives of enhanced survivability on AES I.K. Hatzilau, I.K. Gyparis, J. Prousalidis, S. Perros, A.Dalakos B. SHIP SURVIVABILITY B.2. Survival state - Stages analysis The stages of Survivability can be expressed in probability terms, giving another approach towards the direction of quantification.Next table shows Survivability stages and their relations in terms of probabilities. Presented by I.K. Hatzilau 13

14. Perspectives of enhanced survivability on AES I.K. Hatzilau, I.K. Gyparis, J. Prousalidis, S. Perros, A.Dalakos B. SHIP SURVIVABILITY B.2. Survival state - Stages analysis Presented by I.K. Hatzilau 14

15. Perspectives of enhanced survivability on AES I.K. Hatzilau, I.K. Gyparis, J. Prousalidis, S. Perros, A.Dalakos B. SHIP SURVIVABILITY B.3 Available Power and Survivability Beyond component- and stages-analysis, a third approach to survivability, is to connect it with the amount and the ‘sort’ of power left after the ship has been hit. In that way levels of availablepropulsion and non-propulsion power create areas of survival states. Presented by I.K. Hatzilau 15

16. Perspectives of enhanced survivability on AES I.K. Hatzilau, I.K. Gyparis, J. Prousalidis, S. Perros, A.Dalakos B. SHIP SURVIVABILITY B.3 Available Power and Survivability • Apparently, • the critical powerlevels for defining survival-state areas, • should be specified, depending on type of ship, tactical data etc. Presented by I.K. Hatzilau 16

17. Perspectives of enhanced survivability on AES I.K. Hatzilau, I.K. Gyparis, J. Prousalidis, S. Perros, A.Dalakos B. SHIP SURVIVABILITY B.3 Available Power and Survivability As an example, According to the configuration shown, if after a hit,the available propulsion power is greater than 0.7 and the power available to non-propulsion systems is greater than 0.6, then the ship’s survival state has been decided to lay in the area of “FIGHT REGION” Presented by I.K. Hatzilau 17

18. Perspectives of enhanced survivability on AES I.K. Hatzilau, I.K. Gyparis, J. Prousalidis, S. Perros, A.Dalakos B. SHIP SURVIVABILITY B.3 Available Power and Survivability The link between survivability state and available powers left, can be applied to the embodiment of survivability oriented , ‘fuzzy’ logic decision making aids, into the future automated management and control systems. Presented by I.K. Hatzilau 18

19. Perspectives of enhanced survivability on AES I.K. Hatzilau, I.K. Gyparis, J. Prousalidis, S. Perros, A.Dalakos B. SHIP SURVIVABILITY B.3 Available Power and Survivability The criterion of available power, although applicable to any ship,fits better in AES, due to AES integrated ‘power station’ feature. Furthermore the axis of non propulsion power can be analyzed to more axis, representing groups of non propulsion loads (e.g. available power for defensive weapons, communications etc), now creating volumes of survival-states). Presented by I.K. Hatzilau 19

20. Perspectives of enhanced survivability on AES I.K. Hatzilau, I.K. Gyparis, J. Prousalidis, S. Perros, A.Dalakos B. SHIP SURVIVABILITY B.4 Survivability oriented design A survivable ship results-from selection of highly survivable systems, under a holistic design approach and-from well trained crew that skillfully operate the systems, using “intelligent” interfaces. Presented by I.K. Hatzilau 20

21. Perspectives of enhanced survivability on AES I.K. Hatzilau, I.K. Gyparis, J. Prousalidis, S. Perros, A.Dalakos SUSCEPTIBILITY REDUCTION VULNERABILITYREDUCTION Threat warning Component Redundancy Jamming and detection Component Location / Elimination Signature Reduction Passive Damage Suppression Expendables (e.g. decoys) Active Damage Suppression Threat Suppression Component Shielding Tactics Shock Withstand B. SHIP SURVIVABILITY B.4 Survivability oriented design This table shows generic means for maximizing survivability Presented by I.K. Hatzilau 21

22. Perspectives of enhanced survivability on AES I.K. Hatzilau, I.K. Gyparis, J. Prousalidis, S. Perros, A.Dalakos B. SHIP SURVIVABILITY B.4 Survivability oriented design Contribution of power & propulsion systems for ship’s survivability is critical. Survivable power & propulsion systems qualities are shown in the table. Presented by I.K. Hatzilau 22

23. Perspectives of enhanced survivability on AES I.K. Hatzilau, I.K. Gyparis, J. Prousalidis, S. Perros, A.Dalakos B. SHIP SURVIVABILITY B.4 Survivability oriented design The potential for survivability enhancement in conventional propulsion systems, seems to have come near its limit. Typical measures (like resilient mounting e.t.c.) are shown in the table. Presented by I.K. Hatzilau 23

24. Perspectives of enhanced survivability on AES I.K. Hatzilau, I.K. Gyparis, J. Prousalidis, S. Perros, A.Dalakos B. SHIP SURVIVABILITY B.4 Survivability oriented design ( continued ) Presented by I.K. Hatzilau 24

25. Perspectives of enhanced survivability on AES I.K. Hatzilau, I.K. Gyparis, J. Prousalidis, S. Perros, A.Dalakos C. SURVIVABILITY OF AES -AES incorporates characteristics, that promise high survivability performance. -These are :--Signatures reduction --Flexibility in design and onboard layout --Azipods --Multi-hull forms --Fuel cells --Zonal architectures --Platform management --A.R.M. (Availability Reliability Maintainability) Presented by I.K. Hatzilau 25

26. Perspectives of enhanced survivability on AES I.K. Hatzilau, I.K. Gyparis, J. Prousalidis, S. Perros, A.Dalakos C. SURVIVABILITY OF AES C.1 Signatures ReductionOverall signature of the AES is expected to decrease and consequently susceptibility will decrease.* Acoustic signature-The possibility of placing machineryon higher, above water line decks and the ability of optimally operating prime movers, are expected to decrease underwater radiated acoustic noise.-The fact that noisy reduction gears and variable-pitch propellers are not needed in AES and the perspective of using advanced ‘quiet’ electric propulsion motors and more effective prime mover mounting, promise further reduction of acoustic signature. -The use of high power density fuel cells, as prime movers, will drastically improve acoustic signature. Presented by I.K. Hatzilau 26

27. Perspectives of enhanced survivability on AES I.K. Hatzilau, I.K. Gyparis, J. Prousalidis, S. Perros, A.Dalakos C. SURVIVABILITY OF AES C.1 Signatures Reduction *Thermal signatureReduction of total number of prime movers and optimization of their use, are expected to reduce overall thermal signature, although the subject needs detailed studies.Again, fuel cell technology promises improvement due to low thermal losses.*Electromagnetic signature Due to higher levels of electric power transfer and greater lengths of cabling expected in AES, effective engineering solutions are needed to suppress low frequency electromagnetic signature. Presented by I.K. Hatzilau 27

28. Perspectives of enhanced survivability on AES I.K. Hatzilau, I.K. Gyparis, J. Prousalidis, S. Perros, A.Dalakos C. SURVIVABILITY OF AES • C.2 Flexibility in design and onboard layout • Reduction of required shaft line length down to that • between electric motor and propeller, • ease of choosing location for prime movers, • the ability to cross-link propulsion lines, • overall reduction of vital components(reduction gears, • number of prime movers) and • possibility of component dispersion and better shielding • allow the designer of an AES to implement a highly survivable • ship. Presented by I.K. Hatzilau 28

29. Perspectives of enhanced survivability on AES I.K. Hatzilau, I.K. Gyparis, J. Prousalidis, S. Perros, A.Dalakos C. SURVIVABILITY OF AES C.2 Flexibility in design and onboard layout Generally, a serious hit below waterline at the side keel, is expected to reduce available power of ‘conventional’ propulsion systems about 50%, while the same hit in an AES is expected to cause less than 50% loss of propulsion power.In practice and up to date, the layout flexibility of AES subsystems can be better realized in bigger ships (e.g. LPD’s), or in ships having more than one hulls (e.g. trimaran). Presented by I.K. Hatzilau 29

30. Perspectives of enhanced survivability on AES I.K. Hatzilau, I.K. Gyparis, J. Prousalidis, S. Perros, A.Dalakos C. SURVIVABILITY OF AES C.3 Azipods In AES, the shaft–propeller line can be reduced to a ‘single point’, by integrating electric motor and propeller into one unit, the so-called pod or azimuth thruster. The use of pods also optimizes the hydrodynamic form of the vessel and increases maneuvering and cavitation performance. Noise and maintainability/reparability issues of pods have to be carefully examined. Presented by I.K. Hatzilau 30

31. Perspectives of enhanced survivability on AES I.K. Hatzilau, I.K. Gyparis, J. Prousalidis, S. Perros, A.Dalakos C. SURVIVABILITY OF AES C.4 Multi–hull forms Multi-hull forms, such as Trimaran,(others being catamaran, pentamaran etc)exploit electric propulsion design flexibility more effectively, without compromising weapons and sensors spacing. Presented by I.K. Hatzilau 31

32. Perspectives of enhanced survivability on AES I.K. Hatzilau, I.K. Gyparis, J. Prousalidis, S. Perros, A.Dalakos C. SURVIVABILITY OF AES C.4 Multi–hull forms Side keels of trimaran physically protect the main keel, reducing the possibility of loosing propulsion motors all together and consequently ship’s vulnerability is reduced. Side systems could be azipods (preferably powered by fuel cells). (Numerous studies have shown that trimaran transverse-metacentric height is very high and the ship has exceptional reserve buoyancy. Both of those characteristics enhance ship’s survivability ). Presented by I.K. Hatzilau 32

33. Perspectives of enhanced survivability on AES I.K. Hatzilau, I.K. Gyparis, J. Prousalidis, S. Perros, A.Dalakos C. SURVIVABILITY OF AES • C.5 Fuel Cells • Fuel Cell technology maturing, will fully utilize AES potential for survivability enhancement, since it will contribute • to AES full sectioning (zoning) and • - to AES signature reduction . • Fuel Cell usage improves recoverability and susceptibility, both main components of survivability. • Nevertheless, many issues (like power density, fuel storage e.t.c.) have to be fully developed, in order to exploit fuel cell advantages in a frigate-size AES. Presented by I.K. Hatzilau 33

34. Perspectives of enhanced survivability on AES I.K. Hatzilau, I.K. Gyparis, J. Prousalidis, S. Perros, A.Dalakos C. SURVIVABILITY OF AES • C.6 Zonal architectures • The inherent characteristic of AES to integrate propulsion • and electric power subsystems under common power sources, • favors implementation • of ‘zonal’ architectures. • - At the same time progress in • power conversion technology • favors • scalable power conversion. Presented by I.K. Hatzilau 34

35. Perspectives of enhanced survivability on AES I.K. Hatzilau, I.K. Gyparis, J. Prousalidis, S. Perros, A.Dalakos C. SURVIVABILITY OF AES C.6 Zonal architectures Presented by I.K. Hatzilau 35

36. Perspectives of enhanced survivability on AES I.K. Hatzilau, I.K. Gyparis, J. Prousalidis, S. Perros, A.Dalakos C. SURVIVABILITY OF AES C.6 Zonal architectures Zonal architectures, after careful shipwide load distribution, contribute to full sectioning . Consequently they enhance survivability, since only severe damage can render the ship powerless. All loads can be supplied by any primary power source and by either side power branch. Presented by I.K. Hatzilau 36

37. Perspectives of enhanced survivability on AES I.K. Hatzilau, I.K. Gyparis, J. Prousalidis, S. Perros, A.Dalakos C. SURVIVABILITY OF AES C.7 Platform management AES, due to its --full electrification, --integration of propulsion and electric power systems and --favoring of zonal architectures, can better interface with modern I.C.M.S. (Integrated Control and Monitoring Systems) with distributed processing nature. Well integrated I.C.M.S.’s help crews fight the ship more effectively. Presented by I.K. Hatzilau 37

38. Perspectives of enhanced survivability on AES I.K. Hatzilau, I.K. Gyparis, J. Prousalidis, S. Perros, A.Dalakos C. SURVIVABILITY OF AES C.7 Platform management Furthermore, an AES I.C.M.S., which incorporates asurvivability oriented knowledge-based system,built according relations betweenavailable power and ship’s survival states, candrastically enhance survivability, since : it will aid crews to rapidly visualize after-hitdamage condition and use available power left more smartly, it will aid decision-making, (particularly if fed with tactical situation data) and it will help in more realistic training (by simulating survivability degradation scenaria). Presented by I.K. Hatzilau 38

39. Perspectives of enhanced survivability on AES I.K. Hatzilau, I.K. Gyparis, J. Prousalidis, S. Perros, A.Dalakos C. SURVIVABILITY OF AES • C.8 A.R.M. (Availability Reliability Maintainability) • AES has the potential for improved A.R.M. because : • The use of advanced electric motors and power electronics, built in modular fashion, allows gracefully degraded operation • The operation of prime movers is optimized. • It is possible to serve several systems of one shaft line, • from those of the other shaft line. • It is receptive to modern I.C.M.S.’s and smart systems • and so can incorporate features • of preventive and prognostic maintenance. Presented by I.K. Hatzilau 39

40. Perspectives of enhanced survivability on AES I.K. Hatzilau, I.K. Gyparis, J. Prousalidis, S. Perros, A.Dalakos D. CONCLUSIONS -For the present, survivability cannot be measured ; It can be estimated comparatively, but even qualitative comparison is complex and application specific. -The proposed methodology, for ship’s survivability evaluation, is the analysis to componentsand stages. -The proposed criterion , for power/propulsion systems contribution to ship’s survivability, is the power that is availableafter a hit(amount and type). This criterion is more easily applied in AES (where power and propulsion systems are integrated). -Further work is needed, in order to define specific indexes and/or penalty factors, that will allow quantitative survivabilitycomparisons and assignments. Presented by I.K. Hatzilau 40

41. Perspectives of enhanced survivability on AES I.K. Hatzilau, I.K. Gyparis, J. Prousalidis, S. Perros, A.Dalakos D. CONCLUSIONS The main remarks concerning AES potential for enhanced survivability are : -AES gives the opportunity to ship designers to prioritize survivability, without compromising a lot in other attributes. -Overall signatureof the AES is expected to decrease and consequently susceptibility will decrease. -Azipod propulsors, using new high power density motors, reduce vulnerability. -AES flexibility in design and layout along with exploitation of novel multihulls, decrease susceptibility and vulnerability drastically. -The promising fuel cell technology, the zonal architecture and computerized intelligent control and monitoring systems, are the keys for full exploitation of AES survivability potential. Presented by I.K. Hatzilau 41

42. Perspectives of enhanced survivability on AES I.K. Hatzilau, I.K. Gyparis, J. Prousalidis, S. Perros, A.Dalakos E. BIBLIOGRAPHY 1. Capt. C. N. Calvano “Course Notes on Principles of Ship Design and Systems Engineering”, NPS Monterey. CA, 2000. 2. LtCdr K A Howard et al ‘Comparative Vulnerability Of Electric And Conventional Propulsion Systems’ Proceedings of 1st International Symposium on All Electric Ship, (AES’97), Paper A.2.5. 3. R W G Bucknall A R Greig ‘An Electric Aaw Frigate’, Proceedings of 1st International Symposium on All Electric Ship, (AES’97), Paper A.2.7 4. C D Horne, A J Whithead, D Webster, ‘Naval Electric Power Control and Monitoring Systems – A view of Future’, Proceedings of Eleventh Ship Control Systems Symposium, Vol 2, 1997, pp 439-454 5. G N Bishop, NA Shelley, M J S Edmonds, ‘Electric Propulsion of Surface Fighting Ships’, Proceedings of Eleventh Ship Control Systems Symposium, Vol 2, 1997, pp 157-171 6. LCdr J V Amy Jr et al. ‘Shipboard Electric Power Distribution: Ac Versus Dc Is Not The Issue, Rather How Much Of Each Is The Issue’, Proceedings of 2ndInternational Symposium on All Electric Ship, (AES’98), Paper 4-II. 7. M Benatmane et al. ‘Electric Power Generation And Propulsion Motor Development For Us Navy Surface Ships’, Proceedings of 2nd International Symposium on All Electric Ship, (AES’98), Paper 5-I. 8. P Nicod J.P., P Simon ‘A Step Ahead In Electric Propulsion With Mermaid’, Proceedings of 2nd International Symposium on All Electric Ship, (AES’98), Paper 13-II. Presented by I.K. Hatzilau 42

43. Perspectives of enhanced survivability on AES I.K. Hatzilau, I.K. Gyparis, J. Prousalidis, S. Perros, A.Dalakos E. BIBLIOGRAPHY 9. A T Luckett, D S Webster, I. Barendregt, ‘ EUCLID Joint Programme 16.01 – Sea Systems Integration’ Proceedings of 3rd International Symposium on All Electric Ship, (AES2000), pp. 54-59. 10. P T Norton, P E Thompson, ‘ The naval electric ship of today and tomorrow ’, Proceedings of 3rd International Symposium on All Electric Ship, (AES2000), pp. 80-85. 11. S A Bogh, ‘ Reliability and safety of electric ships’ Proceedings of 3rd International Symposium on All Electric Ship, (AES2000), pp. 262-267. 12. M T W Bolton, M I Parkin, J Mabey, P Rotttier, ‘Opportunities for integrated control and monitoring in the all-electric ship’, Proceedings of 3rd International Symposium on All Electric Ship, (AES2000), pp. 268-273. 13. J van Vugt, J van der Burgt, C S Smit, ‘Power management for damaged electrical systems in ships’, Proceedings of 3rd International Symposium on All Electric Ship, (AES2000), pp. 274-279. 14. Capt R. K. Barr, “Automated Ship Survivability Systems”, Proceedings of Ninth Ship Control Systems Symposium, Vol 1, 1990, pp 1.190-1.198. 15. L.B. Mayer, “Survivability of the Platform Under Combat damage”, Proceedings of Ninth Ship Control Systems Symposium, Vol 4, 1990, pp 4.100-4.113. 16. B. Taylor, Cdr P. MacCillivray, “Total Ship Survivability”, Proceedings of Tenth Ship Control Systems Symposium, Vol 2, 1993, pp 2.221-2.237. Presented by I.K. Hatzilau 43