Proceedings of the VTT Symposium 24, Seminar on Ship Vibration, ESPOO’82, Technical Research Centre of Finland (summary)

(1)

—•

U D C D/y.12.037:534.2:534.4

Key words:

ships, ship hulls, marine propellers, vibration

P1982-7

VTT SYMPOSIUM 24

SEMINAR ON SHIP VIBRATION

Espoo, May 5 1982

Organized by

the Technical Research Centre of Finland, Ship Laboratory

Lisapainos, syyskuu 1985

TT/

VALTION TEKNILLINEN TUTKIMUSKESKUS STATENS TEKNISKA FORSKNINGSCENTRAL TECHNICAL RESEARCH CENTRE OF FINLAND Espoo 1982

(2)

iSBN 9 5 1 - 3 8 - 1 5 9 7 - 8 ISBN 0 3 5 7 - 9 3 8 7

Julkaisija - Utgivaie - Publisher

Valtion teknillrnen tutkimus: 3skus ( V T T ) , Vuorimiehentie 5, 02150 Espoo 15 puh. vailide (90) 4561, teleks 122972 vttha sf

Statens tekniska forskningscentral ( V T T ) , Bergsmansvagen 5, 02150 Esbo 15 tel. va-xel (90) 4561, telex 122972 vttha sf

Techmcal Research Centre of Finland ( V T T ) , Vuorimiehentie 5, S F - 0 2 1 5 0 Espoo 15, Finland phone internat. + 358 0 4561, telc.x 122972 vttha sf

V T T , Laivatekniikan laboratório, Tietotie 1, 02150 Espoo 15 puh. vailide (90) 4561

V T T , Skeppstekniska laboratoriet, Datavagen 1, 02150 Esbo 15 t e l z v ü x e l ( 9 0 ) 4561

V T T , Ship Laboratory, Tietotie 1,02150 Espoo 15 phone internat. + 358 0 4561

(3)

FOREWORD

S i n c e t h e f i r s t s h i p v i b r a t i o n s e m i n a r ( L a i v o j e n v a r a h t e -l y t j a n i i d e n t o r j u n t a , VTT s e m i n a a r i s a r j a N:o 2 2 , Espoo 1980) o r g a n i z e d b y VTT i n 1979, c o n s i d e r a b l e p r o -g r e s s i n t h i s f i e l d h a s been made. The p u r p o s e o f t h i s second s e m i n a r i s t o p r e s e n t t h e c u r r e n t s t a t e o f r e s e a r c h a c t i v i t i e s .

The s h i p v i b r a t i o n r e s e a r c h i n t h e VTT S h i p L a b o r a t o r y has been l a r g e l y c a r r i e d o u t w i t h i n a j o i n t p r o j e c t w i t h COMECON c o u n t r i e s . The f i r s t f i v e - y e a r p r o j e c t was com-p l e t e d i n 1980. The second com-p r o j e c t s t a r t e d i n 1981 and i s m a i n l y d e a l i n g w i t h s u p e r s t r u c t u r e and a f t e r b o d y v i b r a t i o n s . The p r e d i c t i o n methods f o r p r o p e l l e r e x c i t a t i o n , t r e a t e d i n t h e f i r s t p a p e r , now i n c l u d e t h e e f f e c t o f c a v i t a t i o n , t o o . E x p e r i m e n t a l v e r i f i c a t i o n i s made p o s s i b l e b y t h e d e v e l o p m e n t o f e q u i p m e n t f o r p r e s s u r e measurements and c a v i t a t i o n p h o t o g r a p h y . P r o p e l l e r e x c i t a t i o n f r o m t h e p o i n t o f v i e w o f a s h i p y a r d i s d i s c u s s e d i n p a p e r no. 2. D e v e l o p m e n t i n t h e c a l c u l a t i o n methods a r e p r e s e n t e d i n p a p e r s no. 3 and 4. A c c o r d i n g t o e x p e r i e n c i e s g a i n e d f r o m t h r e e d i m e n s i o n a l f i n i t e e l e m e n t m o d e l s , i t i s p o s -s i b l e t o p r e d i c t t h e v i b r a t i o n l e v e l w i t h r e a -s o n a b l e a c c u r a c y . New f e a t u r e s , s u c h as an e a s y m o d i f i c a t i o n o f mass d i s t r i b u t i o n and a r e a l i s t i c t h r e e d i m e n s i o n a l f l u i d -s t r u c t u r e i n t e r a c t i o n c a p a b i l i t y , c a n now b e i n c o r p o r a t e d i n t h e m o d e l . M o d a l s y n t h e s i s t e c h n i q u e s a r e c u r r e n t l y b e i n g d e v e l o p e d . The e x c i t e r t e s t s y s t e m now i n c l u d e s a h y d r a u l i c s h a k e r , c o n t r o l l e d by a d e s k - t o p c o m p u t e r . The same c o m p u t e r a l s o g a t h e r s and p r o c e s s e s s i g n a l s f r o m t h e v i b r a t i o n

(4)

4

-t r a n s d u c e r s . T h i s s y s -t e m , d e s c r i b e d more c l o s e l y i n p a p e r no. 5 , has been s u c c e s f u l l y used i n t h e p r e d i c t i o n o f v i b r a t i o n l e v e l o f s e v e r a l s h i p s d u r i n g c o n s t r u c t i o n s t a g e .

Our g u e s t s f r o m t h e famous K r y l o v S h i p R e s e a r c h I n s t i t u t e w i t h whom we have had c l o s e and f r u i t f u l c o o p e r a t i o n d u r i n g many y e a r s , p r e s e n t t h e i r v i e w s and r e s e a r c h a c t i v i t i e s i n p a p e r s no. 6 and 7.

Espoo, A u g u s t 1982 J u h a n i S u k s e l a i n e n

(5)

5

-L I S T OF CONTENTS

page

FOREWORD 3 PRESSURE FLUCTUATIONS INDUCED BY A 7

CAVITATING PROPELLER J e r z y M a t u s i a k , F i n l a n d

EXPERIENCES I N DEFINING PROPELLER INDUCED 29 HULL FORCES

Markku K a n e r v a , F i n l a n d

SHIP VIBRATION CALCULATIONS 67 S a k a r i R i n t a l a , F i n l a n d

CURRENT TRENDS I N VIBRATION CALCULATION METHODS 115 M a t t i K. H a k a l a , F i n l a n d

SHIP VIBRATION MEASUREMENTS 135 J e r z y M a t u s i a k , F i n l a n d

STATE OF THE ART OF SHIP'S VIBRATION CONTROL AND 173 INSURING OF SHIP'S VIBRATION STRENGTH I N THE USSR O.M. P a l i y , Yu. N. S h a v r o v , USSR

BASIC ASPECTS FOR DESIGN ESTIMATIONS OF TOTAL 191

S H I P V I B R ? i T I O N S

(6)