Release Note 6.1 - DNV

DNV SOFTWARE – A LEADING PROVIDER OF SOFTWARE FOR RISK

MIGRATION GUIDE

Nauticus Machinery Version 5.5 (2004) to 11.5 (2013)

migration guide

2 | MIGRATION GUIDE | Nauticus Machinery| WWW.DNVSOFTWARE.COM

Date: January/2014

Prepared by DNV Software,

an independent business unit of Det Norske Veritas

© Det Norske Veritas AS. All rights reserved.

This publication or parts thereof may not be reproduced or transmitted in any form or by any means, including copying or recording, without the prior written consent of Det Norske Veritas AS.

WWW.DNVSOFTWARE.COM Nauticus Machinery 11.5 | MIGRATION GUIDE | 3

TABLE OF CONTENTS

1 INTRODUCTION ........................................................................................................................................... 4

2 FEATURE COMPARISON 2004 VERSUS 2013 VERSION........................................................................ 4

2.1 Buoyancy in water or oil ........................................................................................................................ 5

2.2 Joint element ........................................................................................................................................... 5

3 CASE A: 76,000DWT BULK CARRIER ....................................................................................................... 6

3.1 Model information .................................................................................................................................. 6

3.2 Input data ................................................................................................................................................ 6

3.3 Converting models from version 2004 to version 11.5 ........................................................................... 8

3.4 Comparison of results ............................................................................................................................. 9

3.4.1 Bearing loads ...................................................................................................................................... 9

3.4.2 Shaft deflections ................................................................................................................................. 9

3.4.3 Bending moments ............................................................................................................................. 11

3.4.4 Shear force ....................................................................................................................................... 14

3.4.5 Jack correction factor ....................................................................................................................... 16

4 CASE B: GEARED DEMO MODEL ........................................................................................................... 17

4.1.1 bearing loads .................................................................................................................................... 17

4.1.2 shaft deflections and bending moments ........................................................................................... 18

4.2 verification results ................................................................................................................................ 24

5 CASE C: COMPARE WITH ANSYS .......................................................................................................... 26

5.1 Direct coupled model............................................................................................................................ 27

5.2 Geared demo model .............................................................................................................................. 28

6 Conclusion ..................................................................................................................................................... 29


1 INTRODUCTION

The Nauticus Shaft Alignment tool has been available in two “generations” consisting of very different user

interfaces and solvers:

- Version 5.5, also called the “2004-version”; although this version has not been subject to any updates

since 2008 , valid license tags will work until end of 2013

- Version 11.5, also called the “2013-version”; this version is subject to continuous maintenance and

frequent releases

The maintenance of the “2004-version” will be terminated as per end of February 2014 and it will not be possible

to use old license files to open this version after this specific date. Nor will it be possible to open old models in

read-only mode. All existing models need to be converted/upgraded to the 2013-version prior to this date.

The purpose of this document is to give a brief summary of the differences between the two versions (2004

versus 2013) and to demonstrate three typical cases and document that the results are very close. Version 11.5 is

also compared with ANSYS in the third case.

2 FEATURE COMPARISON 2004 VERSUS 2013 VERSION

Version 5.5 (2004) Version 11.5 (2013)

Solver Based on transfer matrix method.

Only supporting 2D analysis.

Using Finite Element Method based on beam

elements with 6 DOFs.

Supporting 2D and3D analysis.

Modeling Build model by drag and drop

- Drag – drop in 3D interface

- Import geometry model from Excel

template directly

- Build model by scripting

Operating

conditions

Maximum 5 operating conditions where one

is “locked” to the open shaft condition

Unlimited number of conditions

Bearing reaction

position

Same value for all conditions. Condition dependent.

Independent setting per operating condition.

Optimization

function

Very sensitive to optimization criteria Easy to use

Provide a summary comparing the results

before and after optimization.

Verification

calculation

Jack calculation can only be set on the first

operating condition

Open condition can only be set on the fifth

operating condition

Jacks and open shafts can be applied in any

operating condition

Buoyancy setting Shaft density is decreased to consider the

buoyancy influence in solver

Considered as buoyancy force. More accurate

Undo/Redo Not supported Supported

Scripting Not supported Supported

Unit and decimal

settings for input

and results

Not supported Supported


Nauticus Shaft Alignment version 11.5 also supports the calculation of the minimum rotational shaft speed

criteria which came into force in the July 2013 revision of DNV Rules Pt.4 Ch. 4 Sec.1 F407. Version 11.5 is

also including a data convert feature which can convert model files of v2004 into the new format of v11.5.

2.1 BUOYANCY IN WATER OR OIL

In version 2004 the buoyancy effect for shafts immersed in water or oil is considered by correcting the shaft

density as shaft density minus water/oil density. This is not a “correct” way to consider the buoyancy effecting

and will influence the whirling natural frequencies. In version 11.5 the solver directly takes the buoyancy force

into the alignment calculation rather than correcting the shaft density. So when you set “BuoyancyCorrection” in

oil/water, the shaft density should remain the same.

In version 11.5 when calculating the buoyancy force, the solver considers the water density as 1085 kg/m3 and

the oil density as 880 kg/m3. However in version 2004 the water density is 1000kg/m

3 and oil density is 850

kg/m3 (these default values can be changed).This will induce small differences in total bearing reaction force.

2.2 JOINT ELEMENT

In version 2004 a Joint is modeled as a point with bending stiffness and shear stiffness.

In version 11.5 beside stiffness properties, a Joint element also has length and diameter. When converting Joint

element from v2004 to v11.5, it will have a default length of 135 mm and its diameter is the same as the adjacent

shaft diameter. Accordingly, the total length of old model and converted model will be different.


3 CASE A: 76,000DWT BULK CARRIER

3.1 MODEL INFORMATION

This model is basing on a real case from one of our software customers.

Vessel type 76,000DWT Bulk Carrier

Engine type HHM-MAN 5S60ME-C8.2 diesel engine

Nominal power 11900kW

Nominal speed 105rpm

Propeller diameter 6700mm

Propeller mass (in air) 20155kg

3.2 INPUT DATA

We calculate and compare the “warm static” condition. In this condition a 0.28mm vertical offset is considered

for all the engine bearings.

INPUT DATA - OPERATING CONDITION (WARM STATIC)

---------------------------------------------------------------------------------------

Bearings:

Id Description Position Extension Offset(V) Offset(H)

[-] [-] [mm] [mm] [mm] [mm]

1 Bearing 1 2499 1090.0 0.000 0.000

2 Bearing 2 5155 400.0 0.000 0.000

3 Bearing 3 10585 320.0 -2.000 0.000

4 Bearing 4 15313 575.0 -3.500 0.000

5 Bearing 5 16171 852.0 -3.500 0.000

6 Bearing 6 17191 1020.0 -3.500 0.000

7 Bearing 7 18211 1020.0 -3.500 0.000

8 Bearing 8 19231 1020.0 -3.500 0.000

9 Bearing 9 20251 510.0 -3.500 0.000

Bearings:

Id Description Position Stiffness

Structural(V) Structural(H) OilFilm Axial


[-] [-] [mm] [N/m] [N/m] [N/m] [N/m]

1 Bearing 1 2499 0.0E+000 0.0E+000 0.0E+000 0.0E+000

2 Bearing 2 5155 0.0E+000 0.0E+000 0.0E+000 0.0E+000

3 Bearing 3 10585 0.0E+000 0.0E+000 0.0E+000 0.0E+000

4 Bearing 4 15313 0.0E+000 0.0E+000 0.0E+000 0.0E+000

5 Bearing 5 16171 0.0E+000 0.0E+000 0.0E+000 0.0E+000

6 Bearing 6 17191 0.0E+000 0.0E+000 0.0E+000 0.0E+000

7 Bearing 7 18211 0.0E+000 0.0E+000 0.0E+000 0.0E+000

8 Bearing 8 19231 0.0E+000 0.0E+000 0.0E+000 0.0E+000

9 Bearing 9 20251 0.0E+000 0.0E+000 0.0E+000 0.0E+000

Bearings - Condition dependent:

Id Description Position Clearance ReacPoint ThermExp(V) ThermExp(H) HullDef(V)

[-] [-] [mm] [mm] [mm] [mm] [mm] [mm]

1 Bearing 1 2499 1.000 0.0 0.000 0.000 0.000

2 Bearing 2 5155 1.000 0.0 0.000 0.000 0.000

3 Bearing 3 10585 0.350 0.0 0.000 0.000 0.000

4 Bearing 4 15313 0.450 0.0 0.280 0.000 0.000

5 Bearing 5 16171 0.450 0.0 0.280 0.000 0.000

6 Bearing 6 17191 0.450 0.0 0.280 0.000 0.000

7 Bearing 7 18211 0.450 0.0 0.280 0.000 0.000

8 Bearing 8 19231 0.450 0.0 0.280 0.000 0.000

9 Bearing 9 20251 0.450 0.0 0.280 0.000 0.000

Shaft elements:

Id Description Position Length DoAft DoFwd Di Mass (calc)

[-] [-] [mm] [mm] [mm] [mm] [mm] [kg]

1 Shaft 0 324.0 510.0 510.0 0.0 520

2 Shaft 324 705.0 593.5 628.8 0.0 1608

3 Shaft 1029 705.0 628.8 664.0 0.0 1798

4 Shaft 1734 493.0 664.0 664.0 0.0 1340

5 Bearing element2227 272.0 664.0 664.0 0.0 739

6 Bearing element2499 818.0 664.0 664.0 0.0 2224

7 Shaft 3317 262.0 664.0 664.0 0.0 712

8 Shaft 3579 100.0 664.0 660.0 0.0 267

9 Shaft 3679 921.0 660.0 660.0 0.0 2473

10 Shaft 4600 100.0 660.0 666.0 0.0 268

11 Shaft 4700 255.0 666.0 666.0 0.0 697

12 Bearing element4955 200.0 666.0 666.0 0.0 547

13 Bearing element5155 200.0 666.0 666.0 0.0 547

14 Shaft 5355 495.0 666.0 666.0 0.0 1354

15 Shaft 5850 100.0 666.0 664.0 0.0 270

16 Shaft 5950 255.0 664.0 664.0 0.0 693

17 Shaft 6205 435.0 664.0 664.0 0.0 1182

18 P.S Flange 6640 105.0 1128.0 1128.0 0.0 824

19 I.S Flange(aft)6745 90.0 1128.0 1128.0 0.0 706

20 Shaft 6835 1610.0 460.0 460.0 0.0 2100

21 Shaft 8445 1815.0 460.0 460.0 0.0 2368

22 Shaft 10260 165.0 470.0 470.0 0.0 225

23 Bearing element10425 160.0 470.0 470.0 0.0 218

24 Bearing element10585 160.0 470.0 470.0 0.0 218

25 Shaft 10745 245.0 470.0 470.0 0.0 334

26 Shaft 10990 295.0 460.0 460.0 0.0 385

27 Shaft 11285 1960.0 460.0 460.0 0.0 2557

28 Shaft 13245 1510.0 460.0 460.0 0.0 1970

29 I.S Flange(for 14755 90.0 1128.0 1128.0 0.0 706

30 Engine flange 14845 90.0 1128.0 1128.0 0.0 706

31 Engine shaft e 14935 55.0 1338.0 1338.0 150.0 599

32 Bearing element14990 323.0 720.0 720.0 150.0 988

33 Bearing element15313 252.0 720.0 720.0 150.0 770

34 Engine shaft e 15565 132.0 1350.0 1350.0 150.0 1465

35 Engine shaft e 15697 132.0 1350.0 1350.0 150.0 1465

36 Bearing element15829 342.0 720.0 720.0 150.0 1046

37 Bearing element16171 510.0 389.0 389.0 0.0 0

38 Bearing element16681 510.0 389.0 389.0 0.0 0

39 Bearing element17191 510.0 389.0 389.0 0.0 0


40 Bearing element17701 510.0 389.0 389.0 0.0 0

41 Bearing element18211 510.0 389.0 389.0 0.0 0

42 Bearing element18721 510.0 389.0 389.0 0.0 0

43 Bearing element19231 510.0 389.0 389.0 0.0 0

44 Bearing element19741 510.0 389.0 389.0 0.0 0

Total 36889 [kg]

External loads:

Position Load Moment Distributed Direction

[mm] [N] [Nm] [N] [-]

14935 118964 0 0 Vertical

15697 -98700 0 0 Vertical

16681 159400 0 0 Vertical

17701 159400 0 0 Vertical

18721 159400 0 0 Vertical

19741 159400 0 0 Vertical

Propeller:

Position MassInAir MassInWater

[mm] [kg] [kg]

1029 20155 17436

Polar mass moment Of inertia (Jp)

Diametral mass moment Of inertia (Jd)

Additional mass due to entrained water (d_m)

Polar mass moment Of inertia of entrained water (d_Jp)

Diametral mass moment Of inertia of entrained water (d_Jd)

Jp Jd d_m d_Jp d_Jd

[kgm^2] [kgm^2] [kg] [kgm^2] [kgm^2]

0 0 0 0 0

3.3 CONVERTING MODELS FROM VERSION 2004 TO VERSION 11.5

The file format for model files is changed from the 2004- to the v11.5-release. The Data convert task can convert

model files into the new format.

Do the following to convert the model file:

- Select a convert from path

- Select a convert to path

- Select the correct path in the look for calculations in… list


- Select one or multiple calculations in the calculation list

- Press the convert button

- Go to the projects and calculations task

- Create a new project or select an existing project

- Press the import button in the calculation toolbar

- Give a path in the import dialog

- Select one or several converted model files

- Press the import button

- The imported calculations will be listed in the calculation list

3.4 COMPARISON OF RESULTS

3.4.1 BEARING LOADS

Bearings Loads v 2004 [N] Loads v11.5 [N] Difference

Bearing 1 305962 305244 -0.23%

Bearing 2 68594 68282 -0.45%

Bearing 3 65170 65493 0.50%

Bearing 4 68763 67701 -1.54%

Bearing 5 106726 107956 1.15%

Bearing 6 163200 163554 0.22%

Bearing 7 152248 150322 -1.27%

Bearing 8 189300 191557 1.19%

Bearing 9 55320 54416 -1.63%

Total 1175282 1174525 -0.06%

3.4.2 SHAFT DEFLECTIONS

Position [mm] Deflection v2004 [mm] Deflection v11.5 [mm] Difference

0 -1.160 -1.152 -0.69%

324 -1.066 -1.060 -0.56%

1029 -0.864 -0.858 -0.69%

1734 -0.671 -0.665 -0.89%

2227 -0.553 -0.551 -0.36%

2499 -0.500 -0.500 0.00%

3317 -0.412 -0.411 -0.24%

3579 -0.402 -0.402 0.00%

3679 -0.400 -0.400 0.00%


4600 -0.438 -0.437 -0.23%

4700 -0.447 -0.447 0.00%

4955 -0.474 -0.474 0.00%

5155 -0.500 -0.500 0.00%

5355 -0.529 -0.529 0.00%

5850 -0.614 -0.614 0.00%

5950 -0.633 -0.632 -0.16%

6205 -0.684 -0.683 -0.15%

6640 -0.778 -0.777 -0.13%

6745 -0.801 -0.800 -0.12%

6835 -0.821 -0.820 -0.12%

8445 -1.312 -1.310 -0.15%

10260 -2.033 -2.033 0.00%

10425 -2.105 -2.105 0.00%

10585 -2.175 -2.175 0.00%

10745 -2.247 -2.247 0.00%

10990 -2.358 -2.357 -0.04%

11285 -2.492 -2.491 -0.04%

13245 -3.234 -3.233 -0.03%

14755 -3.443 -3.442 -0.03%

14845 -3.444 -3.443 -0.03%

14935 -3.444 -3.444 0.00%

14990 -3.445 -3.444 -0.03%

15313 -3.445 -3.445 0.00%

15565 -3.445 -3.445 0.00%

15697 -3.445 -3.445 0.00%

15829 -3.445 -3.445 0.00%

16171 -3.445 -3.445 0.00%

16681 -3.452 -3.449 -0.09%

17191 -3.445 -3.445 0.00%

17701 -3.452 -3.449 -0.09%

18211 -3.445 -3.445 0.00%

18721 -3.451 -3.448 -0.09%

19231 -3.445 -3.445 0.00%

19741 -3.456 -3.453 -0.09%

20251 -3.445 -3.445 0.00%


Deflection chart v11.5

Deflection chart v2004

3.4.3 BENDING MOMENTS

Position [mm] Moment v2004 [Nm] Moment v11.5 [Nm] Difference

0 0 0 0.00%

324 720 711 -1.25%

1029 8659 8645 -0.16%

1734 147518 147375 -0.10%

2227 251349 250963 -0.15%


2499 311074 310532 -0.17%

3317 251008 250537 -0.19%

3579 235133 234669 -0.20%

3679 229503 229041 -0.20%

4600 188701 188204 -0.26%

4700 185471 184964 -0.27%

4955 178313 177780 -0.30%

5155 173788 173228 -0.32%

5355 156500 155972 -0.34%

5850 118183 117729 -0.38%

5950 111239 110800 -0.39%

6205 94741 94340 -0.42%

6640 70597 70261 -0.48%

6745 65803 65482 -0.49%

6835 62368 62061 -0.49%

8445 23077 23011 -0.29%

10260 18549 18754 1.11%

10425 20235 20465 1.14%

10585 22217 22471 1.14%

10745 14114 14340 1.60%

10990 2368 2552 7.77%

11285 -10734 -10603 -1.22%

13245 -69520 -69728 0.30%

14755 -81291 -81762 0.58%

14845 -80812 -81298 0.60%

14935 -79715 -80211 0.62%

14990 -72153 -72652 0.69%

15313 -25230 -25745 2.04%

15565 -3777 -4037 6.88%

15697 8906 8780 -1.41%

15829 10458 10465 0.07%

16171 18689 19042 1.89%

16681 -20851 -20611 -1.15%

17191 20900 21030 0.62%

17701 -20578 -20742 0.80%

18211 19236 18780 -2.37%

18721 -18594 -18362 -1.25%


19231 24867 25790 3.71%

19741 -28213 -27752 -1.63%

20251 0 0 0.00%

Bending moment chart v2004

Bending moment chart v11.5


Bending stress chart v2004

Bending stress chart v11.5

3.4.4 SHEAR FORCE

Position [mm] Shear v2004 [N] Shear v11.5 [N] Difference

0 0 0 0.00%

324 -4446 -4391 -1.24%

1029 -18342 -18115 -1.24%

1734 -204876 -204456 -0.21%

2227 -216344 -215782 -0.26%


2499 -222810 -222220 -0.26%

3317 63707 63663 -0.07%

3579 57479 57462 -0.03%

3679 55116 55109 -0.01%

4600 33486 33572 0.26%

4700 31116 31212 0.31%

4955 25018 25140 0.49%

5155 20235 20377 0.70%

5355 84046 83897 -0.18%

5850 70771 70622 -0.21%

5950 68097 67948 -0.22%

6205 61300 61151 -0.24%

6640 49704 49555 -0.30%

6745 41626 41477 -0.36%

6835 34703 34553 -0.43%

8445 14105 13956 -1.06%

10260 -9115 -9265 1.65%

10425 -11319 -11469 1.33%

10585 -13456 -13606 1.11%

10745 49576 49750 0.35%

10990 46304 46478 0.38%

11285 42530 42704 0.41%

13245 17454 17628 1.00%

14755 -1863 -1690 -9.29%

14845 -8787 -8614 -1.97%

14935 -15588 -15538 -0.32%

14990 -140431 -140380 -0.04%

15313 -150115 -150065 -0.03%

15565 -88908 -89919 1.14%

15697 -103274 -104285 0.98%

15829 -18939 -19951 5.34%

16171 -29194 -30205 3.46%

16681 77531 77751 0.28%

17191 -81868 -81649 -0.27%

17701 81331 81905 0.71%

18211 -78068 -77495 -0.73%

18721 74179 72828 -1.82%

19231 -85220 -86572 1.59%

19741 104079 104984 0.87%


20251 -55320 -54416 -1.63%

3.4.5 JACK CORRECTION FACTOR

The jacking calculation is conducted on condition 1 (cold static condition) when considering the

propeller 50% immersed.

Jack calculation results in v2004

Jack calculation results in v11.5

Comparison of Jack Correction Factors

Correction factors Version 2004 Version 11.5 difference

Jack1 Common method 1.1604 1.1628 0.21%

DNV method 1.2354 1.234 -0.11%



DNV method 1.0032 1.0061 0.29%

4 CASE B: GEARED DEMO MODEL

The geared demo model of v11.5 is calculated both in v2004 and v11.5. This demo model is integrated in

version v11.5. A temporary support is added at position 28837mm with zero offset and a jack is added at

position 41784 mm to measure the reaction load of bearing #5. Both closed shaft and open shaft conditions are

calculated and compared.

The result comparison shows as following

4.1.1 BEARING LOADS

Bearing reaction results of closed shaft condition


Bearing1 312356 312411 0.02%

Bearing2 101314 101285 -0.03%

Bearing3 104439 104450 0.01%

Bearing4 93207 93195 -0.01%

Bearing5 84388 85305 1.09%

Bearing6 162361 159889 -1.52%

Bearing7 98334 99904 1.60%

Total 956400 956438 0.00%


Bearing reaction results of open shaft condition


Bearing1 311736 311790 0.02%

Bearing2 106119 106094 -0.02%

Bearing3 76258 76263 0.01%

Tem support 33609 33614 0.01%

Bearing4 83582 83569 -0.02%

Bearing5 84414 85331 1.09%

Bearing6 162332 159860 -1.52%

Bearing7 98346 99916 1.60%

Total 956400 956438 0.00%

4.1.2 SHAFT DEFLECTIONS AND BENDING MOMENTS

Shaft deflections of closed shaft condition

Position [mm] Deflection v2004 [mm] Deflection v11.5 [mm] Difference

0 -4.289 -4.276 -0.30%

223 -3.936 -3.924 -0.30%

473 -3.541 -3.529 -0.34%

913 -2.846 -2.835 -0.39%

1338 -2.175 -2.164 -0.51%

1465 -1.975 -1.964 -0.56%

2503 -0.500 -0.500 0.00%

5030 1.026 1.030 0.39%

5530 1.077 1.079 0.19%

5552 1.078 1.080 0.19%

12916 -0.446 -0.441 -1.12%

13418 -0.455 -0.451 -0.88%

13916 -0.458 -0.454 -0.87%

14244 -0.459 -0.455 -0.87%

15516 -0.500 -0.500 0.00%

16393 -0.622 -0.62 -0.32%

24641 -0.579 -0.578 -0.17%

25516 -0.500 -0.500 0.00%

26664 -0.555 -0.552 -0.54%

27114 -0.604 -0.602 -0.33%

27168 -0.611 -0.608 -0.49%


27622 -0.666 -0.664 -0.30%

27742 -0.681 -0.678 -0.44%

28032 -0.716 -0.713 -0.42%

28837 -0.795 -0.792 -0.38%

30367 -0.822 -0.819 -0.36%

30462 -0.818 -0.815 -0.37%

30502 -0.817 -0.814 -0.37%

30597 -0.813 -0.81 -0.37%

31974 -0.668 -0.666 -0.30%

32487 -0.597 -0.595 -0.34%

32834 -0.551 -0.549 -0.36%

32844 -0.549 -0.547 -0.36%

33344 -0.503 -0.502 -0.20%

33616 -0.500 -0.500 0.00%

33866 -0.516 -0.515 -0.19%

33966 -0.526 -0.525 -0.19%

34366 -0.584 -0.581 -0.51%

34847 -0.671 -0.667 -0.60%

35194 -0.735 -0.731 -0.54%

35425 -0.779 -0.775 -0.51%

41784 -0.62 -0.617 -0.48%

42709 -0.500 -0.500 0.00%

43574 -0.493 -0.491 -0.41%

44029 -0.496 -0.495 -0.20%

44074 -0.497 -0.495 -0.40%

44474 -0.499 -0.498 -0.20%

44637 -0.500 -0.499 -0.20%

44722 -0.500 -0.499 -0.20%

45097 -0.501 -0.500 -0.20%

45437 -0.500 -0.500 0.00%

45752 -0.501 -0.500 -0.20%

46147 -0.502 -0.501 -0.20%

46542 -0.502 -0.501 -0.20%

46857 -0.500 -0.500 0.00%

47125 -0.499 -0.499 0.00%


Shaft deflections of closed shaft condition in v11.5


Shaft deflections of closed shaft condition in v2004

Shaft deflections of open shaft condition in v11.5


Shaft deflections of open shaft condition in v2004

Bending moments of closed shaft condition in v11.5

Bending moments of closed shaft condition in v2004


Bending moments of open shaft condition in v11.5

The bending moment chart of open shaft condition is not available in v2004. The following chart is drawn by

excel basing on the bending moments in state of vertical plane of open condition in v2004


4.2 VERIFICATION RESULTS

Gap and sag values

Values in V2004 (mm) Values in V11.5 (mm) Difference

Gap 0.1 0.105 4.76%

Sag 1.09 1.092 0.18%

Gap and sag in v11.5


Gap and sag in v5.5

Comparison of Jack Correction Factors

Correction factors Version 2004 Version 11.5 difference


DNV method 1.6258 1.6382 -0.76%


Jack calculation results in v11.5

Jack calculation results in v2004

5 CASE C: COMPARE WITH ANSYS

This comparison is done by DNV Technical Advisory and based on two shaft alignment models. One is the

direct coupled system as CASE A but disregard the buoyancy effect, thermal expansions and all bearings have a

common stiffness of 5.0E9 N/m. The other one is the geared demo model showing as CASE B. The shaft

alignment models were imported into ANSYS (using ANSYS command files) and bearing reaction forces and

whirling was calculated and compared with Nauticus Shaft Alignment v11.5.


5.1 DIRECT COUPLED MODEL

NMCP direct coupled model

Ansys direct coupled model

Bearing loads comparison

Bearing Pos. (mm) NMCP (kN) Ansys (kN) Diff (%)

2499 363.5 363.1 0.11%

5155 50 50.9 -1.77%

10585 76.9 76 1.18%

15313 39 41.6 -6.25%

16171 123.7 122 1.39%

17191 163.9 163.7 0.12%

18211 165.9 166.1 -0.12%

19231 172 171.5 0.29%

20251 62.8 63.2 -0.63%

Total load 1217.7 1217.9 -0.02%


The whirling calculation is considered the relative stiffness as 1E10 N/m.

Whirling natural frequency - forward

Mode NMCP forward (rpm) Ansys forward (rpm) Difference (%)

1 1401 1399 0.14%

2 3094 3089 0.16%

3 4716 4697 0.40%

Whirling natural frequency - backward

Mode NMCP backward (rpm) Ansys backward (rpm) Difference (%)

1 1393 1392 0.07%

2 3025 3020 0.17%

3 4572 4552 0.44%

5.2 GEARED DEMO MODEL

Geared model

ANSYS direct coupled model

Bearing loads comparison

Bearing Pos. (m) Nauticus (kN) Ansys (kN) Diff (%)

2.503 312.4 312.5 -0.03%

15.516 101.3 101.4 -0.10%

25.516 104.4 104.4 0.00%

33.616 93.2 93.2 0.00%


42.709 85.3 86.3 -1.16%

45.437 159.9 157 1.85%

46.857 99.9 101.9 -1.96%

Total 956.4 956.7 -0.03%

The whirling calculation applies a relative stiffness of 1E10 N/m in each bearing. The inertia moments on the

propeller was considered as polar mass moment of inertia = 35000 kg*m^2 and diametrical mass moment of

inertia = 17500 kg*m^2.

Whirling natural frequency - forward

Mode NMCP forward (rpm) Ansys forward (rpm) Diff (%)

1 382 382 0.00%

2 795 793 0.25%

3 938 934 0.43%

Whirling natural frequency - backward

Mode NMCP backward (rpm) Ansys backward (rpm) Diff (%)

1 280 280 0.00%

2 681 680 0.15%

3 872 870 0.23%

6 CONCLUSION

Version 2004 is based on transfer matrix method and only supports 2D analysis. When there are

horizontal loads, it will calculate the vertical- and horizontal planes separately. Accordingly, the

3D analysis in v2004 will not be that accurate compared to more sophisticated FE-based methods.

However, version 2013 (11.5) is based on the FE-method and can do 3D analysis considering the

vertical- and horizontal loads simultaneously.

In this comparison we only consider the 2-D (vertical plane) analysis. Based on the above

comparison, we can conclude that the result differences between v2004 and v11.5 are very small.

The results in v11.5 match quite well with ANSYS-results in CASE C.


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Release Note 6.1 - DNV