Shaft Lateral Analysis Overview


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Presentation delivered by Mohamed Zeid from Berg Propulsion on Nauticus Machinery Course, Rio de Janeiro, September 2012

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Shaft Lateral Analysis Overview

  1. 1. Shaft Lateral Analysis overview
  2. 2. Name: Mohamed Zeid Live in: Sweden Age: 32 Role: Senior Rotordynamics  Engineer.Education:B.Sc. In Naval Architecture & Marine engineering  from faculty of engineering,  Suez Canal University 2003.B S I N l A hi &M i i i f f l f i i S C lU i i 2003AMRINA , Associate Member at Royal Institution of Naval Architects. Practical Experience:[Jun to Sep, 2000], Suez Odense Marine Service (Training).[Jun to Sep,2001:2003], Consulting Engineering Bureau (Training).[Nov2003‐May2004], Ocean Classic International, (Structural analysis ).[May 2004‐Jul 2005], TIMSAH Shipyard , (Hydrodynamics , Structural analysis,...)[Jan 2006‐ ......], BERG PROPULSION, (Blade design, Shafting design and analysis / calculations,.....) DNV Software User Conference  2 Rio ,Sep 2012
  3. 3. Propeller shaft alignment Background, Analysis and Control. Analysis and Control Alignment background Alignment background. • Straight installation for all the bearings and the gearbox for installation  purposes only. purposes onlyShaft analysis overview Sep2012‐MZ‐Rio 3
  4. 4. Alignment background. • Straight installation for all the bearings and   position the gearbox flange to face the flange  of the propeller shaft. of the propeller shaft GB SHAFT Shaft analysis overview Sep2012‐ 4 MZ‐Rio
  5. 5. Alignment background. Alignment calculations? gShaft analysis overview Sep2012‐MZ‐Rio 5
  6. 6. Alignment background. Shaft Analysis in LateralShaft analysis overview Sep2012‐MZ‐Rio 6
  7. 7. Alignment background. • Complete shaft analysis and positioning the shaft line bearings including the  gearbox / main engine to fulfill the allowable loading criteria for all shaft  component. componentShaft analysis overview Sep2012‐ 7 MZ‐Rio
  8. 8. Alignment background.Shaft analysis overview Sep2012‐MZ‐Rio 8
  9. 9. Determine optimum domain.  Operating Condition Straight ahead analysis Vessel loading conditionShaft analysis overview Sep2012‐MZ‐Rio 9
  10. 10. Propeller shaft Analysis and Control. Reposition and adjusting Modeling the shaft system Analysis the bearing NOT Ok Shaft line deflection and  bending stresses. g Ok NOT Ok Bearing loads Ok NOT Ok NOT Ok Other shaft component p (Seals, breaks, couplings,…..) Ok Describe how the bearing positioned (GAP/SAG). Verifying the alignment.  (Jack load) Reporting. R iShaft analysis overview Sep2012‐MZ‐Rio 10
  11. 11. Modeling the shaft system. • The tool used for build the model is NAUTICUS MACHINERY, SHAFT  The tool used for build the model is NAUTICUS MACHINERY, SHAFT ALIGNMENT which developed by DNV. • The shaft system modeled by the geometric of the shaft components. • The model also is including the propeller load, gear tooth  forces, stuffiness and thermal expansion effect. Vertical : Horizontal : • All the above is modeled for different operating  p g conditions as: ‐Propeller static & Gearbox cold. ‐Propeller static & Gearbox warm. Fa Ft ‐Propeller running at full pitch & Gearbox cold. Fr Fbt ‐Propeller running at full pitch & Gearbox warm Propeller running at full pitch & Gearbox warm. r ‐Propeller running at 0‐pitch & Gearbox warm.Shaft analysis overview Sep2012‐MZ‐Rio 11
  12. 12. Shaft line deflection and bending stresses. • Checking the shaft deflection through all conditions and look if there is any  excessive deflection specially near by the bearing location.Shaft analysis overview Sep2012‐MZ‐Rio 12
  13. 13. Shaft line deflection and bending stresses. • Checking the bending stresses through all conditions and look into the bending  stresses specially in the way of the propeller and in between the bearings. M σz-maxShaft analysis overview Sep2012‐MZ‐Rio 13
  14. 14. High slope of the shaft inside the aft stern tube bearing bearing. • Checking the shaft deflection inside the aft stern tube bearing and ensure  Checking the shaft deflection inside the aft stern tube bearing and ensure that there is enough lubricating film between the shaft and the bearing. Lubricant White metal Bearing pressureShaft analysis overview Sep2012‐MZ‐Rio 14
  15. 15. High slope of the shaft inside the aft stern tube bearing bearing. • What s happening in this case?! What’s happening in this case?! The oil film thickness is decreased  by increasing the relative slope  ness [mm] 0.4 0.3 03 0 l film thickn 0.1 0.2 0.2 Slope of shaft, 0.3 03 [mm/m] Minimum oil 0,1 0 M 1 1.5 2 Bearing length / shaft diameterShaft analysis overview Sep2012‐MZ‐Rio 15
  16. 16. High slope of the shaft inside the aft stern tube bearing bearing. • Solution ! Bearing pressureShaft analysis overview Sep2012‐MZ‐Rio 16
  17. 17. High slope of the shaft inside the aft stern tube bearing bearing. • Examples ! p Bearing damaged due to high slope  Bearing material yielded under the  of the shaft inside the bearing. high bearing pressure due to high  slope and the bearing still working. slope and the bearing still workingShaft analysis overview Sep2012‐MZ‐Rio 17
  18. 18. Bearing loads criteria. • Slide surface bearing minimum load ! g The bearing have to be loaded with a minimum load which  avoiding the bearing wiping / burning.Shaft analysis overview Sep2012‐MZ‐Rio 18
  19. 19. Bearing loads criteria. • Slide surface bearing max load ! g The bearing have to be loaded below the maximum load  which avoid to over load the bearing. ‐Projected pressure in aftmost bearing should not exceed  8 bar (Oil lub.). ‐Projected pressure in other journal bearings should not  exceed 12 bar in the lower speed range and 18 bar in the  upper speed range (Oil lub.). • Ensure the direction of the resultant force is far  from the lubricant feeding grooves ! from the lubricant feeding grooves !Shaft analysis overview Sep2012‐MZ‐Rio 19
  20. 20. Bearing loads criteria. • Roller bearing minimum load ! g The bearing have to be loaded with a  minimum load which avoiding the bearing  slipping and hammering effect.Shaft analysis overview Sep2012‐MZ‐Rio 20
  21. 21. Bearing loads criteria. • Roller bearing maximum load ! g The bearing have not to be loaded more than the maximum load which  allowed by the bearing manufacture to achieve the required life time.Shaft analysis overview Sep2012‐MZ‐Rio 21
  22. 22. Other shaft component (Seals, breaks,  couplings…) couplings ) • Seals ‐ In case of one stern tube bearing installations, the deflection of the shaft at the  location of fwd seal is of interest. g p y g ‐ In case of the aft stern tube bearing was slope bored by taking off material from the  aft end of the bearing, The aft seal adjustment tolerance have to be checked.  • Breaks ‐ The brake type and compatibility with the shafting system should be checked . yp p y g y At Rest Start‐up During Operation • Couplings and other components ‐ The couplings and all other integrated devices compatibility with the shafting system  should be checked and related criteria from the device manufacture have to be fulfilled.Shaft analysis overview Sep2012‐MZ‐Rio 22
  23. 23. Describe how the bearing positioned. GAP/SAG • GAP‐SAG method The GAP/SAG method have been found that the most reliable way to  The GAP/SAG method have been found that the most reliable way to describe how the bearings positioned related to each other. y1 SAG A B A B B A SAG GAP y3Shaft analysis overview Sep2012‐MZ‐Rio 23
  24. 24. Describe how the bearing positioned. GAP/SAG • GAP‐SAG method The GAP/SAG method have been found that the most reliable way to  The GAP/SAG method have been found that the most reliable way to describe how the bearings positioned related to each other. SAG x A 1 B A B B A SAG GAP x 3Shaft analysis overview Sep2012‐MZ‐Rio 24
  25. 25. GAP/SAG SAG installation! Seen from aft top t y1 x1 B sag p p.s. x2 x4 s.b B sag A x3 A bottom Rotating forward shaft (B) with dial gauge Vertical sag (A below B) = (x3-x1)/2 B A Horizontal sag (A to s.b. from B) = (x4-x2)/2 sag Rotating aft shaft (A) with dial gauge y3 Vertical sag (B below A) = (x3-x1)/2 Horizontal sag (B to s.b. from A) = (x4-x2)/2Shaft analysis overview Sep2012‐MZ‐Rio 25
  26. 26. GAP/SAG GAP installation! top Seen from aft: y1 A B s.b y2 y4 p.s. y3 bottom Rotating forward shaft (B) with dial gauge gap Vertical gap (at bottom) = y3-y1 Horizontal gap (at s.b. side) = y4-y2 Rotating aft shaft (A) with dial gauge Vertical gap (B below A) = y3-y1 Horizontal gap (B to s.b. from A) = y4-y2Shaft analysis overview Sep2012‐MZ‐Rio 26
  27. 27. GAP/SAG • Why the GAP/SAG is a reliable method? The reason of GAP/SAG reliability is that this method is a describe how the shaft line  The reason of GAP/SAG reliability is that this method is a describe how the shaft line parts relate to each other and then compensating the bearing position to keep the shaft  line as it wanted to come over the change on the hull deflection which changed after  g launching .Shaft analysis overview Sep2012‐MZ‐Rio 27
  28. 28. GAP/SAG • GAP/SAG Tolerance Any alignment calculation have to provide a minimum tolerance of +/ 0.05 mm for both  Any alignment calculation have to provide a minimum tolerance of +/‐ 0.05 mm for both GAP and SAG figures. Why?! ‐ Manufacturing quality. ‐ Tool accuracy in use. ‐ Practical experience. Important note: The GAP and SAG  tolerance they are influencing each other!Shaft analysis overview Sep2012‐MZ‐Rio 28
  29. 29. GAP/SAG • GAP/SAG measuring tools Dial gauge. Laser equipment.Shaft analysis overview Sep2012‐MZ‐Rio 29
  30. 30. Verify that the alignment have been done correctly. correctly After aligning the shaft with the GAP‐SAG method, the alignment  have to be checked that it is done correctly. Jack load method. X [mm] F1 F2 F3 F4 Fj F [kN] F3 = F j ⋅ Corr Fj F3Shaft analysis overview Sep2012‐MZ‐Rio 30
  31. 31. Jack load test. actual jacking curve actual jacking curve 1 including hysteresis from friction X [mm] theoretical  2 jacking curve jacking curve 3 3 1 2 F [kN] FjShaft analysis overview Sep2012‐MZ‐Rio 31
  32. 32. Alignment verfication Load cellShaft analysis overview Sep2012‐MZ‐Rio 32
  33. 33. Alignment verfication Jack load notes! The jack load results can very a lot due to: Jacking Bearing ‐ Shaft manufacturing quality. 60 ‐ Tools accuracy. y 50 ‐ Practical experience. Jack load [kN] 40 30 20 10 0 0 90 180 270 DegreesShaft analysis overview Sep2012‐MZ‐Rio 33
  34. 34. Jack load tips! Checking that the dial gauge not influenced by the jack stiffness and foundation: x x F FShaft analysis overview Sep2012‐MZ‐Rio 34
  35. 35. Jack load tips! 400 Fwd stern bearing Int. bearing Jack correction factor: Cj=1.0154 Knuckle point factor: Cj=0.9727 K kl i f C 0 9727Shaft analysis overview Sep2012‐MZ‐Rio 35
  36. 36. Jack load tips! 1300 Fwd stern bearing Int. bearing Jack correction factor: Cj=1.0370 Knuckle point factor: Cj=0.8917Shaft analysis overview Sep2012‐MZ‐Rio 36
  37. 37. Jack load tips! Bearing with no load, Too much friction loss Stick-slip, oil suction, or jacking to short. pump pulses Check slope ! 0.001 Initial contact Several bearings Jacking until contact ntil in top of bearing unloaded in top of bearingShaft analysis overview Sep2012‐MZ‐Rio 37
  38. 38. Alignment verfication • Strain gauge method Commutat - More complicated measurements Pick-Up or transformer - Require bending moment in the shaft - Costly - Often much time needed to analyse - Few companies are able to carry out the analysis + Accurate + Analytical solution possible for some shafting systems Antenna, Wire around shaft + Hot running condition can be verified + Data stored online Strain gauge PC etc.Shaft analysis overview Sep2012‐MZ‐Rio 38
  39. 39. Reporting • The classification societies have a standard requirements in case of the alignment report is  required. Alignment report structure: p y ‐ Complete shaft analysis. ‐ Alignment method (GAP‐SAG). ‐ Alignment verification (Jack load). ‐ Ali Alignment procedures. t dShaft analysis overview Sep2012‐MZ‐Rio 39
  40. 40. Questions ? Questions and discussion ! BERG PROPULSION PRODUCTION AB Mohamed Zeid Naval Architect - R t d N l A hit t Rotordynamics S i Specialist i li t Direct: +46 31 30 10 736 Mobile: +46 761 175 022 E-mail: Box 1005 475 22 Öckerö Sweden Office: +46 31 976 500 www.bergpropulsion.comShaft analysis overview Sep2012‐MZ‐Rio 40