Stress measurements on a propeller blade of a 42.000 ton tanker on full scale

REPORT NO. 51 M

JANUARY 1964

STUDIECENTRUM T.N.O. VOOR SCHEEPSBOUW EN NAVIGATIE

AFDELING MACHINEBOUW - DROOGBAK lA - AMSTERDAM

(NETHERLANDS' RESEARCH CENTRE TN.O. FOR SHIPBUILDING AND NAVIGATION) ENGINEERING DEPARTMENT - DROOGBAI( A -AMSTERDAM

STRESS MEASUREMENTS ON A PROPELLER BLADE

OF A 42,000 TON TANKER ON FULL SCALE

(SPANNINGSMETINGEN AAN EEN SCHROEFBLAD VAN EEN 42,000 TONS TANKER OP WARE GROOTTE)

by

Ir. R. WERELDSMA

Netherlands Ship Model Basin

Issued by the Council

This report is not to be published unless verbatim and unabridged

RESEARCH COMMiTTEE

Ir. H. Kbssen

Prof. Dr. Ir. J.D. van Manen

Ir. A. Meijer

Ir. A. Oosterveld

Ir. R. Wereldsma

CONTENTS

page

Summary 5

Introduction 5

Instrumentation

6

Measurements and results

9

Interpretation of the results and conclusions

9

Acknowledgement 17

Summary

The pattern of the material stresses in the root of a blade of a propeller operating

beliind a single

screw tanker has been determined by means of strain gauges.

The measured stresses agree with those calculated according to different existing methods.

In the root of the blade a fourfold safety margin against fatigue exists.

1, Introduction

The non uniform flow behind the ship's hull,

causes dynamic phenomena on the propeller,

which should be taken into account in order to

avoid possible critical vibrations.

The propeller excited vibratory forces are

being studied by different people [il [21 [3.1.

The

research

into

the

static and dynamic

stresses in the propeller blade material is a

subject that is not very intensively investigated

up till now

[41 [51.

The shipbuilding industry and the shipowners

(Wilton-Fijenoord N.y. and Shell Tankers N.y.

respectively) initiated an investigation into the

nature of these stresses by means of full scale

measurements . This investigation was supported

by the Netherlands' Research Centre TNO for

Shipbuilding and Navigation and was carried out

in close co-operation with the Netherlands Ship

Model Basin.

The loading ona propeller blade can be divided

into three parts, viz.:

The static and dynamic loading due to the

non uniform propeller inflow.

The dynamic loading due to the vibratory

motions of the propeller during operation.

The loading due to centrifugal and gravity

forces.

The laodings mentioned wider h) and c) depend

on the full scale construction of the ship,

in

particular on the mechanical support of the

propeller.

These dependencies required the execution of

these measurements to be made on a full scale

ship in order to obtain a correct impression of

the stresses.

In order to record oniy the dynamic phenomena

of the propeller, other causes of disturbances

hadto be avoided as muchas possible

andthere-fore a turbine driven ship was preferred.

A newly built turbine tanker with an immersed

volume of 42,000 m3,10,200 S.H.P. at 102 rpm

Figure 1. Body plan and stern arrangement of the tanker.

toad condition

EP 318 AP

ballast condition FR 22_ 0' A.R 26.. 3 5 O AP 20 ER

6

Figure lA. Model wake distribution in the load

con-dition at a speed corresponding to 15.5 knots.

Diameter Pitch at 0.7R Number of bLades Disk oreo DeveLoped oreo Pítch_ diagram Figure 2,

Propeller.

of the four bladed propeller and a speed of 15.5

knots was made available for the measurements.

A body plan of the ship is given in figure 1. The

model wake pattern is shown in figure lA. The

principal dimens ions of the propeller are given

in figure 2.

Strain gauges enabled the strain- and stress

information at the blade root to be picked up

without disturbing the propeller inflow

essen-tially (see figure 3).

High tip speeds and packing problems required

the straingaugesto be glued as close as possible

to the propeller boss. It was desired to carry

out the measurement at 0.25- propeller radius

(0.25 R).

2. Instrumentation

Ten rosettes were glued on one propeller

blade, five on each side of the blade at 0. 25 R

and regularly divided over the chord length (see

figure 4). Each rosette consists of 3 strain

gauges, placed under 45

A complete bridge of Wheatstone was formed

by the active gauge on the blade, a passive

gauge, glued on a disk of the propeller material,

and (in order to avoid temperature differences)

located in the cone of the propeller, and two

)recis ion resistors rotating with the propeller

shaft in the ship.

A0 ¡A = 01.1.3 = OE766 D =6530 mm F7 5002 (Ti (Ti

z=

1. A = 311.90 ni A0 = 11.829 ni

Figure 3.

Photograph of the strain gauges on the

pro-peller blade (without waterproof layer).

In this way 30 bridges rotating with the shaft

were composed. Figure 5 gives a schematic

arrangement of the instrumentation.

An electro- magñetic ally operated switch,

rotat-ing with the shaft, connected alternately one of

the 30 bridges to the silver sliprings on the

shaft.

By means of silver coal brushes the

bridge was connected to the electronic

equip-ment.

During one cycle of 30 measurements the ship

was maintained as good as possible in the same

condition (102 revs per minute of the propeller).

The static strain phenomena were read off on

a strain gauge instrument. The dynamic

pheno-mena were recorded magneticly,simultaneously

with a reference impulse, repeating every

re-volution of the propeller.

The mean pattern of the dynamic behaviour

per revolution was obtained by means of a

cor-relation process of the recorded signal and the

reference impulse [61.

n

a

Face 15 30 27 24 211S

253

a

Back

Figure 4. Location and numbers of the strain gauges on the propeller blade and definition of the direction

(a)

of the principal stress

8

r,-'

D

A Strain gauges

on the

blade

B Dummy gauges in

the cone

C

Electric wires

through the hollow

shaft

D Precision

resistors

and electro - magnetic switch E Silver slip rings

Figure 5. Instrumentation of the propeller shaft.

TABLE I. Average strain of the gauges glued on the propeller blade.

to the instruments

Ballast e on dition

Loaded co ndi ion

fa ce

back

fa ce

back

gauge average

gauge average

gauge

average

gauge average

strain

strain

strain

strain

1

+ 67

16

+ 85

I

+ 92

16 +100 2

- 62

17 o 2

-

39 17

+ 62

3 o 18

- 65

3 o 18

- 30

4 ±200 19

-143

4 +275 19

-143

5 +221 20

-138

5 +258 20

-130

6

- 69

21 o 6

- 47

21 o 7 +276 22

-400

7 +358 22

-400

8 + loo 23

-181

8 + 162 23

-181

9

- 75

24

± 31

9

- 46

24

+ 59

lo

+269 25

-303

10 +288 25

-343

11 o 26 o 11 o 26

- 27

12 O 27

+ 75

12 o 27

+ 44

13 + 150 28

± 75

13 +135 28

+ 38

14

- 13

29

+ 80

14

- 80

29

+ 63

15 o 30

+ 30

15 o 30

- 23

3. Measurements and results

The stress measurements were carried out

for two drafts of the ship (see figure 1) and 102

revs per minute of the propeller during the trial

trip

and

the

maiden

trip of the ship from

Rotterdam to Central America.

During the measurements the isolation

re-sistance of the bridges relative to the ship's hull

was regularly noticed.

Every time when the opportunity occurred the

balance points of the bridges were determined

with stopped propeller and ship (0-points).

The course of the isolation

resistance,

the

balance points for the unloaded and for the loaded

propeller for two drafts of the ship are plotted

in figure 6 to a base of time (For the number

and the location of the strain gauges on the

pro-peller blade, see figure 4).

Clearly is illustrated that the isolation

re-sistance drops suddenly simultaneously with a

change in the balance points. From that instant

the measurement must be qualified as unreliable.

Table I gives a survey of the mean strains of

the 30 gauges for the two drafts.

These mean values, together with the dynamic

signals, give the total pattern of the strain of

the propeller blade material during one

revolu-tion.They are summarized inthe figures 7 and 8

Gauge 8 800 600 ¿00 Mfl ballast condition ° Loaded condition o

o.

-u ".\ 102 rpm. time u-Isolation resistance

for the large and the small draft respectively.

The O

position indicates the vertical top

posi-tion of the blade.

With the theory of elasticity the

principal

perpendicular stresses and their direction can

be determined from the three records obtained

per rosette.

In this way the principal stresses and their

direction

(a)

can be determined as a function of

the blade rotation.

For the large and the small draft these stresses

are given in the figures 9 and 10. The definition

of a is given in figure 4.

4. Interpretation of the results and conclusions

The pattern of the two principal stresses shows

that for the three points in the centre of the

chord (rosettes II,

III, IV and VII, VIII, IX) the

smallest principal stress is negligible in regard

to the largest stress. The latter

stress

is

directed along the radius. From this it follows

that the material in the centre of the chord is

loaded

simply

by compressive and tensile

stresses. This result can be understood easily.

The stresses at the leading and trailing edges

of the profile (rosettes

I,

V, VI and X)

in-dicate the presence of centrifugal force. The

Gouge 22 ¿00 O

r

kstopped propeller Isolation resistance time

,-Figure 6. Course of the balance points of the loaded and unloaded propeller blade for two draíts of two strain gauge bridges. 9 C Q L u, o C., E 5topped propeller o' \

\

ballast condition o' 30 days \

-..

loaded condition

Io

2700 3600

D)

g

D,

Course

of the

strain

during

one revoLution

I

100 micro strain

18

IIIIIaIIIIIuIuIuuIIlIvIuuuulIuluIuII

III'I'IIu'pIIuIuuu'IIpu'uIluua'uuII'II'

22 23 24 IuIuIIIIuuuIIIuuiuIIUhlIIliiftuuiiuuIuI

flhluUIflhiuuisflhlU

ix

25 26 27

Uil.

I

2829 30

ii,..i...uui.,niiiiIIliuIiuu.iuuuuiiilI

3600

Figure 7. Pattern of the strain of the 30 strain gauges for the loaded condition at 102 rpm of the propeller

(10,200 S.H.P.)

w

4-J PM

Course of the strain

during one revoLution

1ioo micro strain

i

2 3

ulIuluhliui

hIIIuIuuhuuhhhuuuuuhIuhhIU 1111111

lull

I $ 4 5 6

.Iu.uu,.aI....ul.,.

Ut

7 8 9 I

.-liii..

I

ill

TT

13 14 15 IllhhhUhllillIll

11111111 II

f ace

back

ô°

g0

1800 270°

propetter position t

Ô° 900 1800

propetter position

IIIIliiiiinu,..aiililliii

lui

16

i

uuII,luuIuuIuuIuhIuuuuII.u.IluuIIIuuuI

u'uuuIuuIv$IuuuuuuIuuI..uIliflhuuu,

Figure 8.

Pattern of the strain of the 30 strain gauges for the bal]ast

_{condition at 102 rpm of the propeller}

(10,000 S.H.P.)

II

.4-. v_w

Course

one

of the strain during

revolution.

I ¿100 micro strain

16 18

IIIIUIIIHIIIIIIIIPIHIIIIIIP...uiull

I 9 20

IHfflOJnhIIII1I11hII1IluuI1II

11IIII111II11111111''1IIII

'411 23 24

IllIIIIIIIINIIIuIIIII'

°'Iilffi

IIIIIIIIIIIP1I1I''Iu'1H

r----.

--i-rîm-.

.,, -r-rrrrri 27

IIIIIIHuiuuuiiuiuiiuiiiuiiriuuiuuiuul

X

28 29 30

uiuiiuuuiuuu,iiuuiiuuuIllIliIflhIuiui

iIiIIIiiIiUUuiiiifluiiiuiiuuiiiilIIII

-.-rrr-r-n--n-piiîrrjïpî-i-i-i-r,

v

Course of the strain during

one revolution.

I

¿100 micro strain

I

I 2 3 IIIIIIIIIpuIIIIuuIuruuuIuuuuuuIuIuIII UUUIflhIIIISIIIUIIIIIIU

N

10 11 12

I

13 14 15 00 900 _180° 2700 3600 _0° 900 _{180° 2 70°} 3600

propeller position

propeller position

ED

face

_back

4

n

₅ 6 7

'JI

e g

12

'n

L.

I

Course and direction of the

principal stress durin.g one

revolution. I1OOkgI

I

25°

.-.uuuI

011hllnniiiiiiiiiooiiiiiiiiiiiiilll

DI

cr1 cr2

Illlllliiiiioiiiiiiiiii

IlflIUfluiHiiuiIlihiui.ui..usuiiIH

0

o;

IIKhIIIiiiiiiiiiiiiiiiiiiiiiiiiiiIIII

u.

o

Y

00 _90° 1800 _270° 350°

propeller

position

E

--face

X

a;

uuIIuuuIßuIuhuuuullI$uuu,UUPuuuNuIuI uuu,uuu.I.p I + 00 _{go° 180° 270°} 3600

propeller

position

back

Figure 9. Course of the principal stresses ( c and

Oi) during one revolution of the propeller at the 10 points

for the loaded condition at 102 rpm of the propeller (10,200 S. H. P.) w

E

Course and direction of the

principal stress during one

revolution. I1OOkg/,.

I25

'

o;

IIIIilhiiiøiiiiiiiIOhiuui,niiiuiuil

IIUIUUup..u.iuuINtii

ululi

Io;

iL1I! IIJ

a;

l2

ODiiIIIIIIII0''IIIIII

Q

IIßNOhIII0hI111II"'0II

11 IT rl II! II

a;

a-2

.'J w

o

L

Course and direction

o,f the

principal stress

during

one

rev otutiori

!e1OOkg,éri

h25°

iuIiIIuuuIIuiiluu,IuI,uuIiuIiI,iHIuuuI

uTh

0°

90°

1800 270° 3600 00

_90°

1800

_270°

_360°

propeller

position »

_{propeller position}

face

back

Firgure 10.

Course of the principal stresses (

o and a ₎ during one revolution of the propeller at the lU points

for the ballast condition at 102 rpm of the propeller (10,000 S. H.P.)

13

w

Course and direction of the

principal stress during one

revoLution

11OOkg/cri

[Q25°

g; 0<.

iuIIuuIInhlIiuIIliuuuuuuuuusIii....i

..

C-q;

g;

2

IIIIIIIUP,uuIIuIIIIII

1111Hh11111!IØH

i:

0L.

pIIinu'uoIII'°"°'IlIgg

uuunluuuuuIuIuuIuuuiiiuuiui,uuuuuu.

12

ci

0<. luIuuuiuIIuuuuInuIIlIilhIuuuPuIuIIuuuI --

i...i...uuiIIIIflhIi...

°

I

ci; I

I

ci;

ci;

n

u;

ci; 0<

nl

ci;

OIIIIIIIflhIioiIOIIIioioiioiHhIII

o;

0<

v-Illllllllliiiuiiiiilliiiiiiiiiiiiiillll

u;

I.,.

I'll'

0< _{t'i 'FIT}

'4

TABLE II

Average value and course of the largest principal stresses in kg/cm2 measured in the root of a

propeller blade as a function of the propeller rotation (p) for the ballast condition of the

ship

at 102 rpm of the propeller.

p

Rosette

p

Rosette

I II III IV V VI VII VIII IX X

0 +195 +514 +580 +552 +329 0 +138 -265 -670 -528 +71

lo

+210 +538 +596 ±577 4-346 lo +144 -285 -716 -5 +72 20 +210 ±534 +596 +570 +339 20 +149 -293 -729 -609 +77 30 +201 +502 +580 +551 +311 30 +144 -285 -687 -632 +76 40 +202 +503 ±571 +541 +350 40 +140 -285 -671 -634 +76 50 +201 +490 +553 +525 +285 50 +141 -269 -680 -629 +75 60 +189 +467 +523 +487 +261 60 ±138 -253 -658 -629 +71 70 +178 +432 ±493 +453 +236 70 +131 -236 -604 -624 +69 80 ±170 +399 ±463 +426 ±221 80 +127 -221 -567 -583 ±67 90 +164 ±379 ±442 ±410 +210 90 +123 -208 -530 -556 ±66

loo

±160 ±365 4-425 +396 +210 100 ±120 -199 -497 -523 +66 110 +159 +357 +418 +393 +213 110 +119 -194 -463 -485 +67 120 ±160 +355 +412 +393 +222 120 ±118 -189 -450 _.453 +68 130 +160 +354 +410 -1-394 +230 130 -4-118 -186 -446 -433 ±69 140 +160 +356 +407 +398 +236 140 ±119 -184 -441 -424 ±69 150 +159 ±364 +413 +399 +242 150 +119 -184 -439 -414 ±68 160 +161 +379 +431 +409 ±255 160 +120 -187 -445 -414 +68 170 +168 +399 +449 +429 +274 170 +124 -196 -478 -417 +69 180 ±174 +409 +465 ±452 ±291 180 ±127 -206 -511 -443 +72 190 +176 +406 +465 +454 +299 190 ±130 -206 -521 -459 +74 200 ±174 +374 -'-454 +445 +293 200 +130 -195 -519 -466 ±76 210 +160 ±341 +440 ±408 ±264 210 ±130 -177 -474 -448 +74 220 +146 +317 -'-393 +372 ±248 220 +125 -163 -410 -423 +73 230 +142 +300 +371 ±354 ±240 230 +116 -153 -381 -395 +72 240 +140 +290 ±361 +341 +223 240 +113 -144 -368 -369 ±72 250 ±138 +284 +341 ±329 +230 250 +108 -139 -352 -348 +71 260 +143 +281 +330 ±326 +231 260 +107 -137 -340 -337 +70 270 ±134 +280 ±330 +328 +231 270 +106 -137 -336 -328 ±70 280 +135 +283 +329 +330 +232 280 ±106 -140 -338 -322 ±69 290 +132 +299 +331 +335 +237 290 ±105 -145 -341 -322 ±69 300 +137 +318 +35a ±353 +247 300 +106 -157 -350 -324 ±69 310 +145 +346 +377 +385 +256 310 +108 -167 -375 -338 +69 320 ±149 +376 +404 +404 +269 320 +112 -181 -424 -361 +68 330 +158 +420 +436 +429V +290 330 +116 -198 -457 -384 -'-68 340 +173 +458 +480 +464 +306 340 +122 -215 -498 -417 +68 350 +185 +485 ±539 +500 ±318 350 ±131 -244 -577 -466 -'-69 360 ±195 +514 +580 +552 ±329 360 +138 -265 -670 -528 71

\xerage

+140 +390 +450 +430 +265

Average +125

-210 -500 -450 +70

TABLE III

Average value and course of the largest principal stresses in kg/cm2 measured in the root of a

propeller blade as a function of the propeller rotation (p) for the ballast condition of

_{the ship}

at 102 rpm of the propeller.

15 P Rosette p Rosette

II III IV V VI VII VIII IX X

0 +174 ±373 +433 +499 +292 0 +81 -254 -694 -626 ±124 10 +180 -4-393 +465 +520 +305 10 +82 -273 -723 -659 +127 20 +182 +424 ±482 +332 +314 20 +83 -286 -721 -642 +127 30 +181 +429 +482 +329 +313 30 -f89 -293 -716 -600 +122 4b +180 +428 +470 +518 -f307 40 +90 -298 -712 -584 +121 50 +182 +425 +462 +520 +303 50 +91 -303 -707 -608 +123 60 ±181 +422 +455 +513 +297 60 +94 -296 -706 568 +120 70 +176 +404 +429 +426 +280 70 +95 -283 -686 -510 +117 80 +168 +369 ±397 +454 +258 80 +96 -268 -597 -457 +114 90 +158 -f337 +371 +419

238

90 +95 -251 -553 -406 +112 100 +150 +311 +336 +390 +223 100 -f94 _{-236 -517 -363} +112 110 +144 +288 +308 +355 +213 110 ±93 -222 -477 -344 +113 120 +141 +274 +294 +362 +206 120 +92 -214 -455 -332 +114 130 +139 +269 +288 +358 4203 130 +91 -207 -466 -324 +116 140 +139 +262 +286 +354 ±200 140 +90 -201 435 -318 +117 150 +139 +260 +284 +352 +201 150 +89 -196 -429 -316 +117 160 +141 +266 +291 +359 +208 160 +88 -196 -432 -333 +117 170 +146 +283 +323 +387 +221 170 +87 -199 -464 -387 +118 180 +149 +302 +346 +402 +231 180 ±86 -207 -500 -426 +120 190 +152 +313 +357 +445 +238 190 +87 -212 -521 -431 +122 200 +147 +398 +348 +405 +236 200 +89 -210 -523 -391 +123 210 +143 +288 +310 +371 +215 210 +92 -192 -464 -326 +121 220 +132 +258 -f246 +343 +192 220 +91 -180 -401 -247 --119 230 +126 +233 +241 -320 +182 230 -i-91 _{-168 -368} -223 +120 240 +122 +217 +221 -i-309 +174 240 +89 -159 -343 -217 +121 250 F118 f203 +204 +294 +166 250 87 -149 -327 -201 +122 260 +115 +191 +194 +298 +161 260 +85 -140 -315 -193 +122 270 +114 +186 +194 -f286 +160 270 +84 -141 -306 -189 +122 280 ±116 +178 +202 +296 +163 280 +81 -146 -318 -203 +122 290 +118 +192 +210 +304 -f170 290 +80 -149 -335 -230 +121 300 +122 +206 +227 +323 +178 300 +78 -154 -376 -256 -i-119 310 +130 +223 -1-250 -1-355 +197 310 +75 -167 -381 -299 +119 320 +138 +252 +278 386 +220 320 +75 -180 -455 -370 +119 330 +147 +278 +316 +415 +236 330 +76 -196 -522 -436 +119 340 +157 +305 +368 ±453 f258 340 77 -214 -579 -506 -119 350 +167 +337 +408 +489 +278 350 +79 -234 -644 -580 +12 360 +174 +373 -f433 +499 +292 360 +81 -254 -694 -626 +124 Average +150 ±301 -1-335 -4-395 _{230 Average ±87 -215 -500 -400} ±123

¡6 rosette rosette 1I T2 _900kgjc 90° 190° 270° 360°

lift reduction due to covitotion

Figure 11.

Pattern of the largest principal stress

at rosettes III and Vm.

measured stresses are on both sides of the

profile tensile stresses. On the other hand the

asymmetric location of the two profile surfaces

relative to the neutral line will amplify

this

effect. Both perpendicular principal

stresses

are roughly of the same order of magnitude and

are not directed radially and tangentially. No

sharp conclusions can be drawn.

Figures 9 and 10 show that the part in the

centre of the profile has the highest stresses

static as well as dynamic.

The leading and trailing edge of the profile are

more or less statically loaded, and the stresses

are relatively small.

Tables II and III give the largest principal

stresses as a function of the rotational blade

position for the 5 points on both sides of the

blade and for the two drafts.

These tables show that the draft of the ship

has a very small influence on the stresses.

Having in mind the measured stress patterns,

only the heavily loaded part of the material will

be considered further (rosettes

III and VIII).

The pattern of the radially directed stresses

of rosettes III and VIII is more accurately given

in figure 11.

The maximum value of this stress occurs at

about

1OC

after the vertical top position. This

means that in that position the lift force on the

blade has a maximum value or that the point of

application is on the largest radius.

5% of the average thrast

30 e E 10/. o! the prapelLer 0° radius thrust eccentrieity

Figure 12. Experimentally determined thrust

eccentri-city and trmverse force occurring on a single screw

ship W.

In both .cases it can he concluded that the total

thrust of the propeller does not apply in the

shaft centre. This is in accordance with the

results of ref. [11 (see figure 12)

Immediately after the top value of the blade

loading (100) a disturbance occurs as a small

reduction of the stresses.

The possibility exists that the decrease in

loading is due to cavitation (see figure 11).

Figure 13 shows the strain gauge signal of a

measurement on a five bladed propeller*).

Be-sides the normal influence of the non uniform

flow (indicated with a thin line) a plain

disturb-ance can be distinguished. This disturbdisturb-ance is

caused by propeller vibrations. This illustrates

that the propeller vibrations affect essentially

the dynamic blade load

(see also the

intro-duction). For a four bladed propeller the

dis-turbances coincide with the disturbance of the

wake field and therefore cannot be detected.

In order to get an impression about

admissi-bility of the occurring stresses, the 'Smith"

diagram of fatigue for the propeller material

(cunial)

is given in figure 14 (Lips Propeller

Works, Drunen, Holland),

The point of the highest loading (rosette VIII)

is indicated in this diagram.

It can be concluded that stresses four times

as large as the measured static and dynamic

loading would lead to fracture.

°) Due to the humidity of the strain gauges, the mean strain and the total pattern of the stresses could not be measured in a reliable way

Figure 13. Strain signal in the root of a blade of a five bladed propeller operating behind a single screw tanker.

e _{transverse force} 'q i revolution

3000 2500 2000

.15001

10004-C ?00 500 w 4 300

measured with rosette 91111

500 100' 1500 _{2000 2500 3000} average stress in kg,,"crr

Figure 14. Diagram of fatigue of the material of the

investigated propeller (cunial).

Finally stress calculations are carried out for

the investigated propeller, according to different

existing methods [71 [8] [9 [10 [ii].

These methods give oniy the average stress for

the maximum thickness of the blade profile

. The

method of Burrill gives only the stress at 0.25 R

of the blade.

The results of these analyses are given in

fi-gure 15.

The experimentally obtained average stress is

also indicated

in the figure

and is in

good

agreement with the theoretical results.

It must be remarked that the presented results

of the measurements are obtained as an average

value for many revolutions of the propeller [6]

and that the measurements took place during

fair weather conditions. During less favourable

conditions the stresses may temporarily

in-crease.

All calculations are in good agreement with each

other for the small radii. For larger radii the

results are different.

A comparison between the calculated and the

measured values for

0. 8 R would give

infor-mation on the accuracy of the various methods

for larger radii. The measurement concerned

could possibly be made on model base.

1000 1100

-0125

Burr i IL

Experimentally obtained

value with rosette Ylil

Dimensionless radius ( r/R)

Figure 15.

Theoretically obtained stresses of the

pro-peller blade as a function of the radius according to

different methods [71 [81 [9] [101 [ii].

The pattern of the measured stresses illustrates

clearly that the variable part of the stresses

cannot be neglected. The top-top value of the

variations amounts to about 80% of the average

value (rosette VIII).

For an optimum design of the propeller an

analysis of these variable loadings and stresses

of the propeller blades would be desirable.

5. Acknowledgement

For the successful execution of this type of

expensive measurements needing a relatively

long time, due to the dynamic character,

a

perfect preparation of the measurements and

a

good co-operation with the shipowner

_during

the trip is required.

Therefore a vote of thanks must be passed to

the Shipbuilders

_{Wilton-Fijenoord N. V., who}

prepared the instrumentation of the propeller

and the propeller shaft and assisted during

the

measurements and to the Shipowner Shell Tankers

N.y., who put the ship to disposal in order

to

carry out the measurements smoothly.

7

800 -C D 600 D E w -C o LOO -In w

200-(J) Conolty(I):without alLowance ConoUy(ll) : with allowance

0

0.2 0.L

4-0.6 08

'e

Wereldsma, R.:

'Experimental determination

of thrust eccentricity and transverse forces, gene-rated by a screw propeller". International

Ship-building Progress, Vol. 9, No. 95, July 1962.

Schuster, S.: "Schiffbauliche Modellversuchstechnik I und ll".Archivfür Technischès Messen, Nov. & Dez. 1955.

Tachmindji, A.J. and Dickerson, M.C.:"The

mea-surement of thrust fluctuation and free space

oscillating pressures for a propeller". Report

No. 1107, Jan.1957, David Taylor Model Basin, Washington, U.S.A.

Conolly,

J. E.: "Strength of propellers".

Trans-actions of the Royal Inst. of Naval Architects,

Vol. 103, Number 2, April 1961.

"Study of measuring the propeller blade strength'

Report no. 28 of the Shipbuilding Research

As-sociation of Japan,

December 1959, Tokyo, Japan.

References

Manen, J.D. van and WereldsmaR, :"Dynamic

mea-surements on propeller models". International

shipbuilding Progress, Vol. 6, No. 63, Novem-ber 1959.

Technical Memono. 36/60, August 1960, Admiralty

Experiment Works, Haslar,

Gosport, Hunts, England.

Schroefberekening volgens Ros ingh (Strength calcu-lation according to Rösingh). Technische Weten-schappelijke Aldeling, Wilton- Feijenoord, Rot-terdam, Holland.

Romsom, J.A. :" Propeller strength calculation".

The Marine Engineer and Naval Architect. Vol. 75, No. 900 & 901, Febr. & March 1952.

Burrill, L.C. :" A short note on the stressing of

marine propellers". The Shipbuilder and Marine Engine-Builder, Vol. 66, No. 619, August 1959.

Taylor, D.W. :"The speed and power of ships".

Published by United States Government Printing Office, Washington, 1943, Vol.

66, No. 619,

REPORTS AND PUBLICATIONS OF THE NETHERLANDS RESEARCH CENTRE T.N.O.

FOR SHIPBUILDING AND NAVIGATION

Reports No. i S The determination of the natural frequencies of ship vibrations (Dutch).

By prof. ir H. E. Jaeger. May 95O. No. 2 S Confidential report, not published. July 1950.

No. 3 S Practical possibilities of constructional applications of aluminium alloys to ship construction.

Byprof. irH.E. Jaeger. March1951.

No. 4 S Corrugation of bottom shell plating in ships with all-welded or partially welded bottoms (Dutch). By prof. ir H.E. Jaeger and ir H.A. Verbeek. November 1951.

No. 5 S Standard-recommendations for measured mile and endurance trials of sea-going ships (Dutch). By prof. ir J.W. Bonebakker, dr ir W.J. Muller and ir E.J. DieM. February 1952.

No. 6 S Some tests on stayed and unstayed masts and a comparison of experimental results and calculated stresses (Dutch). By ir A. Verduin and ir B. Burghgraef. June 1952.

No. 7 M Cylinder wear in marine diesel engines (Dutch). By ir H. Visser. December 1952. No. 8 M Analysis and testrng of lubricating oils (Dutch).

By ir ILN.M.A. Malotaux and ir J.G. Smit. July 1953.

No. 9 S Stability experiments on models of Dutch and French standardized lifeboats.

By prof. ir H.E. Jaeger, prof. ir J.W. Bonebakker and J. Pereboom. in collaboration with A. AudigS. October 1952. No. 10 S On collecting ship service performance data and their analysis.

By prof. ir J.W. Bonebakker. January 1953.

No. 11 M The use of three-phase current for auxiliary purposes (Dutch). By ir J.C.G. van Wijk. May 1953.

No. 12 M Noise and noise abatement in marine engine rooms (Dutch). By "Technisch-Physische Dienst T.N.O.- T.H."April 1953.

No. 13 M Investigation of cylinder wear in diesel engines by means of laboratory machines (Dutch). By ir H. Visser, December 1954.

No. 14 M The purification of heavy fuel oil for diesel engines (Dutch). By A. Bremer. August 1953.

No. 15 S Investigation of the stress distribution in corrugated bulkheads with vertical troughs. Byprof. ir H.E. Jaeger, ir B. Burghgraef and I. van der Ham. September 1954. No. 16 M Analysis and testing of lubricating oils H (Dutch)

-ByirR.N.M.A. MaiotauxanddrsJ.B. Zabel. March1956.

No. 17 M The application of new physical methods in the examination of lubricating oils. By ir. R.N.M.A. Malotaux and dr F. van Zeggeren. March 1957

No. 18 M Considerations on the application of three phase current on board ships for auxiliary purposes especially with regard to fault protection, with a survey of winch drives recently applied on board of these ships and their influence on the generating capacity (Dutch).

By ir J.C.G. van Wijk. February 1957. No. 19 M Crankcase explosions (Dutch).

By ir J.H. Minkhorst. April1957.

No. 20 S An analysis of the application of aluminium alloys in ships's structures. Suggestions about the riveting between steel and aluminium alloy ship' structures.

Byprof. irH.E. Jaeger. January1955.

No. 21 S On stress calculations in helicoidal shells and propeller blades. By dr ir J.W. Cohen. July, 1955.

No. 22 S Some notes on the calculation of pitching and heaving in longitudinal waves. By ir J. Gerritsma, December 1955.

No. 23 S Second series of stability experiments on models of lifeboats. By ir B. Burghgraef. September 1956.

No. 24 M Outside corrosion of and slagformation on tubes in oil-fired boilers (Dutch). By dr W.J. Taat. April 1957.

No. 25 S Experimental determination of damping, added mass and added mass moment of inertia of a shipmodel. By ir J. Gerritsma. October 1957

No. 26 M Noise measurements and noise reduction in ships. By ir G.J. van Os and B. van Steenbrugge. May 1957.

No. 27 5 Initial metacentric height of small seagoing ships and the inaccuracy and unreliability of calculated curves of righting levers. By prof. ir J.W. Bonebakker. December 1957.

No. 28 M Influence of piston temparature on piston fouling and piston-ring wear in diesel engines using residual fuels. By ir H. Visser. June 1959.

No. 29 M The influence of hysteresis on the value of the modulus of rigidity of steel. By ir A. Hoppe and ir A.M. Hens. December 1959.

No. 30 S An experimental analysis of shipmotions in longitudinal regular waves. By ir J. Gerritsma. December 1958.

No. 31 M Model tests concerning damping coefficients and the increase in the moments of inertia due to entrained water on ship's propellers. By N.J. Visser. October 1959.

No. 32 S The effect of a keel on the rolling characteristics of a ship. By ir J. Gerritsma. July 1959.

20

No. 33M The application of new physical methods in the examination of lubricating oils. (Continuation of report No. 17 M.) By ir R.N.M.A. Malotaux and dr F. van Zeggeren. November 1959.

No. 34 S Acoustical principles in ship design. By ir J.H. Janssen. October 1959. No. 35 S Shipmotions in longitudinal waves.

By ir J. Gerritsma. February 19GO.

No. 36 S Experimental determination of bending moments for three models of diffirent fullness in regular 'vaves.

ByirJ.Ch. de Does. April1960.

No. 57 M Propeller excited vibratory forces in the shaft of a single screw tanker. By dr ir J.D. van Manen and ir R. Wereldsma. June 1960. No.38 S Beamknees and other bracketed connections.

Byprof. ir N.E. Jaeger and ir J.J.W. Nibbering. January1961.

No. 39 M Crankshaft coupled free torsional - axial vibrations of a ship's propulsion system. By ir D. van Dort and N.J. Visser. September 19(33.

No. 40 S On the longitudinal reduction factor for the added mass of vibrating ships with rectangular cross-section. By ir W.P.A. Joosen and dr J.A. Sparenberg. April 1961.

No. 41 S Stresses in flat prupeller blade models determined by the moiré-method. By ir FR. Ligtenberg. May 1962.

No. 42 S Application of modern digital computers in naval-architecture. By ir N.J. Zunderdorp. June 1962.

No.43 C Raft trials and ship's trials with some underwater paint systems. By dra P. de Wolf and A.M. van Londen. July 1962.

No. 44 S Some acoustical properties of ships with respect to noise control. Part I. By ir J.11. Janssen. August1962.

No.45 S Some acoustical properties of ships with respect to noise control. Part II. By ir J.H. Janssen. August1962.

No. 46 C An investigation into the influence of the method of application on the behaviour of anti-corrosive paint systems in seawater. By A.M. van Londen. August 1962.

No. 47 C Results of an inquiry into the condition of ship's hulls in relation to fouling and corrosion. By ir H.C. Ekama, A.M. van London and drs P. de Wolf. December 1962.

No.48 C Investigations into the use of the wheel-abrator for removing rust and millscale from shipbuilding steel (Dutch). (Interim report). By irJ. Remmelts and L.D.B. van den Burg. December 1962.

No.49 S Distribution of damping and added mass along the length of a shipmodel. By prof. ir J. Gerritsma and W. Beukelman. March 1963.

No. 50S The influence of a bulbous how on the motions and the propulsion in longitudinal waves. By prof. ir J. Gerritsma and W. Benkelman. April 1963.

No. 51 M Stress measurements of a propeller blade of a 42. 000 ton tanker on full scale. By ir R. Wereldsma. September 1963.

No. 52 C Comparative investigations on the surface preparation of shipbuildingsteel by usingwheelabrators and the application of shop-coats. By ir H.C. Ekama, A.M. van Londen and ir J. Remmelts. July 1963.

No. 53 S The braking of large vessels.

Byprof. ir N.E. Jaeger. August 1963.

No. 54 C A study of shipbottom paints in particular pertaining to the behaviour and action of anti fouling paints. ByA.M. van Londen. September 1963.

No. 55 S Fatigue of ship structures.

By ir J.J.W. Nibbering. September 1963.

Communications

No. 1 M Report on the use of heavy fuel oil in the tanker "Auricula" of the Anglo-Saxon Petroleum Company (Dutch). August 1950.

No. 2 S Ship speeds over the measured mile (Dutch). ByirW.H.C.E. Rösingh. February 1951.

No. 3 5 On voyage logs of sea-going ships and their analysis (Dutch).

By prof. ir J.W. Bonebakker and ir J. Gerritsma. November 1952.

No. 4 S Analysis of model experiments, trial and service performance data of a single-screw tanker. By prof. ir J.W. Bonebakker. October 1954.

No. 5 S Determination of the dimensions of panels subjected to water pressure only or to a combination of water pressure and edge compression (Dutch). Byprof. ir N.E. Jaeger. November 1954.

No. 6 S Approximative calculation of the effect of free surfaces on transverse stability (Dutch). By ir L.P. Herlst. April 1956.

No. 7 5 On the calculation of stresses in a stayed mast. By ir B. Burghgraef. August 1956.

No. 8 5 Simply supported rectangular plates subjected to the combined action of a uniformly distributed lateral load and compressive forces in the middl plane.

By ir B. Burghgraef. February 1958.

No. 9 C Review of the investigations into the prevention of corrosion and fouling of ships' hulls (Dutch). By ir H.C. Ekama. October 1962.

REPORT No.69 M

MARCH 1965

STUDIECENTRUM T.N.O. VOOR SCHEEPSBOUW EN NAVIGATIE

AFDELING MACHINEBOUW - DROOGBAK lA - AMSTERDAM

(NETHERLANDS' RESEARCH CENTRE T.N.O. FOR SHIPBUILDING AND NAVIGATION) ENGINEERING DEPARTMENT - DROOGBAK IA - AMSTERDAM

*

STRESS MEASUREMENTS ON A PROPELLER MODEL

FOR A 42,000 D.W.T. TANKER

(SPANNINGSMETINGEN AAN EEN SCHROEFMODEL

VOOR EEN 42.000 TONS D.W. TANKER)

by

Ir. R. WERELDSMA

(Netherlands' Ship Model Basin)

IRO

Issued by the Council

This report is not to be published unless verbatim and unabridged

RESEARCH COMMITTEE

Ir. H. KLAASSEN

Prof. Dr. Ir. J. D. VAN MANEN

Ir. A. MEIJER Ir. A. OOSTERVELD Ir. W. H. C. E. RÖSINGH Ir. R. WERELDSMA

CONTENTS

page

Summary

5

Introduction

5

i

Strain-gauge technique

6

2

Results of the model experiments

7

3

Extrapolation to full size values

8

Summary

The stresses in the blade of a propeller model were experimentally determined and are compared with theoretically analysed

stress distributions and with full size measurements.

The differences between theory and experiment due to scale effects are discussed.

The differences between theoretically analysed and experimental results are of such a nature that additional investigations in this field are recommended.

Introduction

Strength analysis of screw propellers is a scarcely

investigated subject up till now, since it is difficult

to give a simple mathematical description of the

construction. The existing methods, applicable to

screw propellers are based on estimations, practical

experience and theoretical considerations [1 .

. . 6].

A comparison is made between the results of

the various methods of analysis, applied to one

Pitch diagram

1.0 R 5093

propeller, absorbing 10624 HP at 102 r.p.m. The

propeller characteristics and the hull form of the

tanker are defined by Figs i and 2 respectively.

A diverging set of curves is obtained (Fig. 3).

It is remarkable that all applied methods give

more or less the same results for 0.25R.

The question rises which method of analysis

gives the best approximations for

the actual

stresses.

Full size measurements carried out at 0.25R [7]

5

as

1k 5178

--09R .pp* ./ oB R

1L

.1P?

-

I/ 07R

L

aB R Q5

1k

y1.1uI'

ii

I I 'h I -R

I1

1L'

u:

¿218

-

I

r

I 0=A P 20=F P

Fig. 2. Body plan of the ship

Diameter D

=

6530 mm AO/A = 0.443

Pitch at 0.7R FO7R= 5002 mm = 0.766 Number of blades Z

=

4

Disk area A = 33.490 m2 Developed area A0 = 14.829 m'

6

1100

-show an acceptable agreement with the results of

all applied methods (Fig. 3).

Therefore experiments had to be carried out at

larger radii to justify the use of one method.

As full size measurements are very expensive

and time consuming it was decided to carry out

model measurements at different radii and in order

to check the scale experiment to compare the

measured stress at O.25R with the previously

ob-tained full size measurements.

If the propeller model to be investigated (scale

1:27.5) is manufactured of the same material as

the full size propeller (Cunial) and if the

measure-ments are carried out at equal Froude numbers

(Fr = V/ \/gl)

the stresses and strains in

the

propeller model and in the full size propeller are

in the ratio of the scale factor if scale effects were

absent.

These effects, however, are introduced by

fric-tion phenomena (boundary layer) and are

dis-cussed in paragraph 3.

Fig. 5

i

Strain-gauge technique

The stresses at the blade surface are determined

by means of strain-gauge rosettes. The

arrange-ment of the straingauge bridges and sliprings is

given in Figs 4, 5 and 6.

The wires connecting the strain-gauges to the

bridge are countersunk into the blade material, in

order to avoid hydrodynamic disturbances as

much as possible. It is assumed that disturbances

from the watertight covers of the strain-gauges are

negligible.

Due to this countersinking the blade sections

are damaged and the stress distribution disturbed.

Fig. 4. Location of strain-gauges

Therefore the measurements for the various

radii were carried out each on a separate blade of

the same propeller model.

The applied gauges are the smallest obtainable

in order to be as much as possible in line with the

full size arrangement. The relatively larger area

of the gauges on the model introduces a reduction

of the extreme values. This effect has to be taken

o

lue experimentally obtained

on full size [6]

\Burrill [2)

200 - Canolly(I):without allowance Conolly(lj) with allowance

0 25

+ 4 -F

0.2 CL 0.6 0.8

/R

Fig. 3. Results of various stress analysis methods 500 800 600 1000 -E coo z

into account when comparisons are made with the

full size results.

2

Results of the model experiments

In order to study the effect of power absorption

on the propeller blade stresses and to select equal

propeller conditions for the comparison with the

full size measurements the stress measurements at

rosette no.

1

(see Fig. 7) are carried out for

dif-ferent propeller loads (various propeller r.p.m.).

These results are given in Fig. 8 where for a

constant speed of the model the measured strains

of the three gauges of rosette no. i are plotted to

Fig. 6

a base of propeller r.p.m. (Fig. 8 bottom). The

principal perpendicular stresses were determined

from the three strains with the theory of elasticity.

In Fig. 8 (top) the largest principal stress is

plotted to a base of propeller r.p.m. Fig. 9 shows

the overall loading conditions of the propeller and

the stress in the propeller blade at the location of

rosette no. 1 as a function of propeller r.p.m.

In this Figure two conditions are indicated, for

which more detailed measurements are carried out.

For condition I (model speed = 1.52 rn/sec and

propeller

r.p.s. = 8.9)

the

stress

distributions

along the chords at various radii are recorded

(Fig. lo).

8

E

o

Fig. 7. Situation of the strain-gauge rosettes on the back of the propellerbiades

+1

-lo

Rotation

Speed of model = 152 rmmfs.e.

Fig. 8. Stress measurement at rosette no. i

Fig. 9. Loading conditions of the propeller

For conditions I and II the stresses at midchord

are measured and plotted as a function of the

radius (see Fig. li, curve I and II respectively).

For the comparison with the full size

measure-ments the above mentioned results have to be

extrapolated.

3

Extrapolation to full size values

According to Taylor's formula du' blade stress

can be expressed as follows [8].

C1P 1

Zn S2lo2

where

S = Compressive stress

P = Power at the propeller

Z = Number of blades

n = r.p.m.

C1 = Coefficient dependent of pitch ratio H1D

102= Length of blade element at O.2R

S = Blade thickness

C1P (D\2 (D\

C1 ¡D\2 (D'

P

= ZnD3

ksi

ki02)

=

. ) nD3

Sc =

20

Speed ( fufl size ) 15.5 knots

Speed C mode ) o 1.52 rn/sec.

0025

r

0010 rm 15 , 0.0230 o 10 l-1 its-i_E 35 25 20 15 90 t 100 r.pm. (fui 5ize) 110 7.7 8,92 r p.o. (modet) 9 10 77 8 lo

R. P S of the p opeILer n,odet

77 8.92

7 8 10 11

R P 5 of the propeller model

15

o -10 -20 -30 -LO o -10 -20 -30 -LO O -10 -20 -30 -4° o -10 -20 -30 Midc tord, '10 0.8 R. 0.6 R O LR o 2 lnducaton of rosettes (see fi.7).

g

025R r.p s. of h. propeller 8.92

speed of the model 1.52

Fig. IO. Maximum principal stress on back of the propellerbiade

where

D = Diameter of propeller

For a given propeller and its model holds:

- K

P

where K1 is a constant equal

C

-nD3

for full size and model.

S =

K2

(n.D)°

S =

K2 .KQ . n2 - D2

From this it follows:

(Stress)o1i size (KQ . 2.D2)0011_size

(Stress) model - (KQ n D2) model

(KQ)ful( size

(KQ) model

where

KQ = torque coefficient

a = length scale factor = 27.5

(r.p.m. of propeller)

fullsize

fi

= time scale factor

(r.p.m. ofpropeller) model a2 fi2

It can be shown that the material stress due to the

centrifugal forces are proportional with n2D2. For

different KQ for model and full size the scaling of

the centrifugal stresses and the stresses due to the

hydrodynamic attack differs accordingly.

The full size measurements are carried out

under the following conditions:

propeller diameter

D= 6530mm

r.p.m. of the propeller n=

102

absorbed horsepower

P = 10624 HP

propeller torque

= 0.0208

hence

(K0)911size n2D°

The model measurements, carried out for the two

conditions can be extrapolated according to the

above formulae.

For condition I holds (sce Figs 8 and 9):

(KQ)model = 0.0230

a = 27.5

fi

= 0.19 = l/\/a

(Stress)model = 25.8 kg/cm2

0.0208 (Stress)fullsize

0.0230X 27.5 X 25.8 = 650 kg/cm2

For condition II holds:

(KQ) model = 0.0208

a = 27.5

0.22

(Stress)model = 15.1 kg/cm2

(Stress)ïu size 0.0208

-0208x36.5x 15.1 = 550 kg/cm2

The differences of the stresses predicted from both

conditions are considerable and caused by scale

effects of the wake field of the hull, due to the

differences in the Re number ,by incorrectness in

the prediction of the centrifugal stresses for

condi-tion I and by inaccuracies of the measurements.

O 50 10 curve curve II Npv892/sec Vm 1.52 rYsec. (Condition I> 7.7/sec Vm 1.52 rn/sec (Condition fl( 0.25 0.4 06 0.8 1

Dimensionless radius (_{VR)_____o.}

Fig. 11. Distribution of largest principal stress on model at midchord points for conditions I and II

9 a s rp s m/sec 40 30

II

20 u,

lo

E 1100 1000 800 I, / . 600 E 200 o, 400 Experimentally obtained on full size [6]

- - Taylor

[1]

- Conolly [L]

- Rornscm [3]

'\ [Full size predicted

t

Scale effect corrected model measured distribution.

Fig. 12. Comparison of the extrapolated model measured stress

distribution and the

theoretically obtained stress

distribution

Condition II, giving the same dimensionless torque

loading for the full size and model experiments

(K0), is chosen as a base for the extrapolation. A

prediction of the full size stress-distribution

ob-tained from curve II of fig. 11 is given by a dotted

line in fig. 12.

Comparing this prediction with the full size

measurement, a difference is established, due to

the unknown change in load distribution of the

propeller blade and inaccuracies in the

meas-urements. A new curve, corrected for these

un-known effects is indicated by a full line.

This curve, the most reliable experimental curve

to be obtained from full size and model

exper-iments, does not coincide with one of the

theoret-ically obtained distributions as given in Fig. 3.

The remarkable differences between the results of

the measurements and calculations, as can be

observed from Fig. 12, lead to necessary additional

research in this field.

4

Final remarks and recommendations

It is recommended to check the theoretical methods

for the determination of the stress distribution in

a propeller blade by an experimental investigation

with open water propeller tests. Scale effects can

be avoided in that case and various methods of

analysis can be checked more precisely. These

activities can lead to improvements in propeller

strength calculations.

References

TAYLOa, D. W., The speed and power of ships, United States Government Printing Office, Washington, 1943. BURRILL, L. C., A short note on the stressing of marine

propellers. The Shipbuilder and Marine

Engine-Builder, August 1959.

Roriso,J. A., Propeller strength calculation. The Ma-rine Engineer and Naval Architect, February/March

1952.

CONOLLY, J. E., Strength of propellers. Transactions of the Royal Institution of Naval Architects, 1961. Technical Memo no. 36/60 August 1960. Admiralty

Experiments Works, Haslar, Gosport, Hants, England. Schroelberekening volgens Rösingh. Technische

Weten-schappelijke Afdeling Wilton-Fijenoord, Rotterdam, Holland.

WERELDSMA, R., Stress measurements on a propeller blade of a 42,000 ton tanker on full scale. Netherlands Research Centre T.N.O. for Shipbuilding and Navi-gation Report No. 51 M; International Shipbuilding Progress, January 1961; Association Technique

Mari-time et Aeronautique, Session 1963.

MANEN,J. D. VAN, Fundamentals of Ship Resistance and

Propulsion Part B: Propulsion. Publication No. 1 32a of the Netherlands Ship Model Basin.

PUBLICATIONS OF THE NETHERLANDS' RESEARCH CENTRE T.N.O.

FOR SHIPBUILDING AND NAVIGATION

Reports

No. i S The determination ofthe natural frequencies ofship vibrations (Dutch). Byprqf. ir H. E. Jaeger. May 1950.

No. 3 S

Practical possibilities of constructional applications of aluminium alloys to ship construction.

By prof. ir H. E. Jaeger. March 1951.

No. 4 S

Corrugation of bottom shell plating in ships with all-welded or partially welded bottoms (Dutch).

By prof. ir H. E. Jaeger and ir H. A. Verbeek. November 1951.

No. 5 S

Standard-recommendations for measured mile and endurance trials of sea-going ships (Dutch).

By prof. ir J. W. Bonebakker, dr ir W. J. Muller and ir E. J. Die/il. February 1952.

No. 6 S

Some tests on stayed and unstayed masts and a comparison of experimental results and calculated stresses (Dutch).

By ir A. Verduin and ir B. Burghgraef. June 1952. No. 7 M Cylinder wear in marine diesel engines (Dutch).

By ir H. Visser. December 1952.

No. 8 M

Analysis and testing oflubricating oils (Dutch).

By ir R. N. M. A. Malotaux and irJ. G. Smil.July 1953.

No. 9 5

Stability experiments on models ofDutch and French standardized lifeboats.

By prof. ir H. E. Jaeger, prof. ir J. W. Bonebakker and J. Pereboom, in collabor&ion with A. Audigé. October 1952. No. 1 0 5 On collecting ship service performance data and their analysis.

Byprof irJ. W. Bonebakker.Januaiy 1953.

No. 1 1 M The use of three-phase current for auxiliary purposes (Dutch). Bv irJ. C. G. van Wjk. May 1953.

No. 12 M Noise and noise abatement in marine engine rooms (Dutch).

B_y "Technisch-Physische Dierut T.N.O.-T.H." April 1953.

No. 13 M Investigation ofcylinder wear in diesel engines by means oflaboratory machines (Dutch).

By ir H. Visser. December 1954.

No. 14 M The purification of heavy fuel oil for diesel engines (Dutch).

By A. Bre7ner. August 1953.

No. 15 S Investigation of the stress distribution in corrugated bulkheads with vertical troughs.

By pwf. ir H. E. Jaeger, ir B. Burglzgraef and I. van der Ham. September 1954.

No. 16 M Analysis and testing of lubricating oils II (Dutch).

By ir R. N. M. A. Malotaux and drs J. B. Zabel. March 1956.

No. 17 M The application ofnew physical methods in the exarriination oflubricating oils.

By ir R. N. M. A. Malotaux and dr F. van Zeggeren. March 1957.

No. 18 M Considerations on the application of three phase current on board ships for auxiliary purposes especially with regard to fault protection, with a survey of winch drives recently applied on board of these ships and their in-fluence on the generating capacity (Dutch).

By ir J. C. G. van Wjk. February 1957. No. 19 M Crankcase explosions (Dutch).

By ir J. H. Minkhorst. April 1957.

No. 20 S An analysis of the application of aluminium alloys in ships' structures.

Suggestions about the riveting between steel and aluminium alloy ships' structures. By prof. ir H. E. Jaeger. January 1955.

No. 21 S On stress calculations in helicoidal shells and propeller blades. By dr irJ. W. Gohen.July 1955.

No. 22 S Some flotes on the calculation of pitching and heaving in longitudinal waves.

By ir J. Gerritsma. December 1955.

No. 23 S Second series ofstability experiments on models of lifeboats. By ir B. Burghgraef. September 1956.

No. 24 M Outside corrosion ofand slagformation on tubes in oil-fired boilers (Dutch). Bydr W.J. Taat. April 1957.

No. 25 S _{Experimental determination of damping, added mass and added mass moment of inertia of a shipinodel.} By ir J. Gerritsma. October 1957.

No. 26 M Noise measurements and noise reduction in ships.

By ir G. J. van Os and B. van Steenbrugge. May 1957.

No. 27 5 _{Initial metacentric height of small seagoing ships and the inaccuracy and unreliability of calculated curves of} righting levers.

By t'rof. ir J. W. Bonebakker. December 1957.

No. 28 M Influence of piston temperature on piston fouling and piston-ring wear in diesel engines using residual fuels.

By ir H. Visser. June 1959.

No. 29 M The influence of hysteresis on the value of the modulus of rigidity of steel.

By irA.Hoppe and irA. M. Hens. December 1959.

No. 30 S An experimental analysis of shipmotions in longitudinal regular waves.

By ir J. Gerritsma. December 1958.

No. 31 M _{Model tests concerning damping coefficients and the increase in the moments of inertia due to entrained water}

of ship's propellers.

By N. J. Visser. October 1959.

No. 32 5 The effect of a keel on the rolling characteristics of a ship. By ir J. Gerritsma. July 1959.

No. 33 M The application of new physical methods in the examination of lubricating oils. (Continuation of report No. 17 M.)

By ir R. N. M. A. Malotaux and dr F. van Zeggeren. November 1959.

No.34 5 Acoustical principles in ship design. By ir J. H. Janssen. October 1959.

No. 35 S Shipmotions in longitudinal waves.

By ir J. Gerritsma. February 1960.

No. 36 S Experimental determination of bending moments for three models of different fullness in regularwaves. By ir J. Ch. De Does. April 1960.

No. 37 M Propeller excited vibratory forces in the shaft of a single screw tanker.

By dr ir J. D. van Manen and ir R. Wereldsrna. June 1960.

No. 38 5 Beamknees and other bracketed connections.

By prof. ir H. E. .7aeger and ir J. J. W. Nibbering. January 1961.

No. 39 M Crankshaft coupled free torsional-axial vibrations of a ship's propulsion system. By ir D. van Dort and N. J. Vfcser. September 1963.

No. 40 S On the longitudinal reduction factor for the added mass of vibrating ships with rectangular Cross-Section. By ir W. P. A. Joosen and dr J. A. Sparenberg. April 1961.

No. 41 S Stresses in flat propeller blade models determined by the moiré-method. By ir F. K. Ligtenberg. June 1962.

No. 42 S Application of modern digital computers in naval-architecture.

By ir H. J. Zunderdorp. June 1962.

No. 43 C Raft trials and ships' trials with some underwater paint systems.

By drs P. de Wolfand A. M. van Londen. July 1962.

No. 44 S Some acoustical properties of ships with respect to noise-control. Part I. By ir J. H. Janssen. August 1962.

No. 45 5 Some acoustical properties of ships with respect to noise-control. Part Il. By ir J. H. Janssen. August 1962.

No. 46 C An investigation into the influence ofthe method ofapplication on the behaviour ofanti-corrosive paint systems in seawater.

By A. M. van Londen. August 1962.

No. 47 C Results ofan inquiry into the condition ofships' hulls in relation to fouling and corrosion.

By ir H. C. Ekama, A. M. van Landen and drs P. de Wolf. December 1962.

No. 48 C Investigations into the use of the wheel-abrator for removing rust and mii!scale from shipbuilding steel (Dutch) Interim report.

By ir J. Reminelts and L. D. B. van den Burg. December 1962.

No. 49 5 Distribution ofdamping and added mass along the length ofa shipmodel.

By prof. ir .7. Gerrilsina and W. Beukelman. March 1963.

No. 50 5 The influence of a bulbous bow on the motions and the propulsion in longitudinal waves.

By prof ir J. Gerritsrna and W. Beukelman. April 1963.

No. 51 M Stress measurements on a propeller blade of a 42,000 ton tanker on full scale.

By ir R. Wereldsrna. January 1964.

No. 52 C Comparative investigations on the surface preparation of shipbuilding steel by using wheel-abrators and the application of shop-coats.

By ir H. C. Ekama, A. M. van Londen and ir J. Remrnelts. July 1963.

No. 53 S The braking of large vessels.

By prof. ir H. E. Jaeger. August 1963.

No. 54 C A study of ship bottom paints in particular penaining to the behaviour and action of anti-fouling paints.

By A. M. van Londen. September 1963.

No. 55 S Fatigue of ship structures.

By ir J. J. W. Nibbering. September 1963.

No. 56 C The possibilities of exposure of anti-fouling paints in Curaçao, Dutch Lesser Antilles.

By drs P. de Wolf and Mrs M. Meuter-Schriel. November 1963.

No. 57 M Determination of the dynamic properties and propeller excited vibrations of a special ship stern arrangement.

By ir R. Wereldsma. March 1964.

No. 58 S Numerical calcuiation of vertical hull vibrations of ships by discretizing the vibration system.

By J. de VTies. April 1964.

No. 59 M Controllable pitch propellers, their suitability and economy for large sea-going ships propelled by conventional,

directly-coupled engines.

By ir C. Kapsenberg. June 1964.

No. 60 S Natural frequencies of free vertical ship vibrations. By ir C. B. Vmvugdenhil. August 1964.

No. 61 S The distribution of the hydrodynamic forces on a heaving and pitching shipmodel in still water.

By prof. ir J. Gerritsma and W. Beukelman. September 1964.

No. 62 C The mode of action of anti-fouling paints: Interaction between anti-fouling paints and sea water.

By A. M. van Londen. October 1964.

No. 63 M Corrosion in exhaust driven turbochargers on marine diesel engines using heavy fuels.

By prof R. W. Stuart Mitchell and V. A. Ogale. March 1965.

No. 64 C Barnacle fouling on aged anti-fouling paints; a survey of pertinent literature and some recent observations.

By drs P. de Wolf. November 1964.

No. 65 S The lateral damping and added mass of a horizontally oscillating shipmodel.

By G. van Leeuwen. December 1964.

No. 66 S Investigations into the strength of ships' derricks. Part I.

By ir F. X. P. Soejadi. February 1965.

No. 67 5 Heat-transfer in cargotanks of a 50,000 DWT tanker.

By D. J. van der Heeden and ir L. L. Mulder. March 1965.

No. 68 M Guide to the application of "method for calculation of cylinder liner temperatures in diesel engines". By dr ir H. W. van Tijen. February 1965.

No. 69 M Stress measurements on a propeller model for a 42,000 DWT tanker.

By ir R. Wereldsma. March 1965.

Communications

No. I M Report on the use of heavy fuel oil in the tanker "Auricula" of the Anglo-Saxon Petroleum Company (Dutch).

August 1950.

No. 2 S

Ship speeds over the measured mile (Dutch).

By ir W. H. C. E. Rösingh. February 1951.

No. 3 S

On voyage logs of sea-going ships and their analysis (Dutch).

By prof. ir J. W. Bonebakker and ir J. Gerritsma. November 1952.

No. 4- S Analysis of model experiments, trial and service performance data of a single-screw tanker.

By prof. ir J. W. Bonebakker. October 1954.

No. 5 S

Determination of the dimensions of panels subjected to water pressure only or to a combination of water pressure and edge compression (Dutch).

By prof. ir H. E. Jaeger. November 1954.

No. 6 S

Approximative calculation of the effect of free surfaces on transverse stability (Dutch). By ir L. P. Herfst. April 1956.

No. 7 S On the calculation of stresses in a stayed mast.

By ir B. Burghgraef. August 1956.

No. 8 S

Simply supported rectangular plates subjected to the combined action of a uniformly distributed lateral load and

compressive forces in the middle plane. By ir B. Burghgraef. February 1958.

No. 9 C

Review of the investigations into the prevention of corrosion and fouling of ships' hulls (Dutch).

By ir 1-J. C. Ekama. October 1962.

No. 10 S/M Condensed report of a design study for a 53,000 dwt-class nuclear powered tanker.

By the Dutch International Team (D.!. T.) directed by ir A. M. Fabery de Jonge. October 1963.

No. Il C Investigations into the use of some shipbottom paints, based on scarcely saponifiable vehicles (Dutch).

By A. M. van Londen and drs P. de Wolf. October 1964.