Information Models and Functions for CIM in Shipbuilding

7/29/2019 Information Models and Functions for CIM in Shipbuilding

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J M ar Sci Tec hno l (1997) 2:148-162 J o u r n a l ofM arine Scienceand T echnology9 SNAJ 1997

I n f o r m a t i o n m o d e l s a n d f u n c t i o n s f o r C I M i n s h i p b u i l d i n gK A Z U H I R O A O Y A M A a n d T O SH IH A R U N O M O T ODep ar tmen t o f Nava l Arch i t ec tu re and Ocean Eng inee r ing , Facu l ty o f Eng inee ring , Un ive r s i ty o f Tokyo , 7 -3 -1 Hongo , Bunkyo-ku , Toky o113, Japan

Abstract: In or der to m ake s ignificant pro gress in des ign andmanufacturing sys tems, a l l indus tr ies must cons ider integra-t ion . T h i s pape r cons ide rs in fo rma t ion mode l s and func t ionsfo r a comp ute r in teg ra ted des ign and manufac tu r ing s ys tem ins h ipbu i ld ing . T he au thors p ropos e the p roduc t mode l andsevera l a l tera t ive funct ions for des igning a ship ' s s t ructure ,and d eve lop a " s h ip de f in i t ion s ys tem fo r com pute r in teg ra teddes ign and manufac tu r ing . " T h i s s ys tem i s ca l l ed SODAS(Sys tem of Des ign and As s embly fo r Sh ipbu i ld ing) . Anob jec t -o r i en ted concep t i s us ed to deve lop th i s s ys tem. Inorde r to de f ine a s h ip ' s s t ruc tu re , the au thors p ropos e thep r o d u c t m o d e ls o f " p a r ts m e m b e r " a n d " p a r t s c o n n e c ti o n , "a n d t h e p r o d u c t m o d e l s o f " R o o m , " " U n i t , " a n d " M o d u l e "a re in t rod uced to de f ine the com par tmen t s , in t e rna l s t ruc tu re sand in te rmed ia te p roduc t s o f a s h ip . T he re fo re , a l l i n fo rma-t ion abo u t a p rodu c t f rom the des ign to the p roduc t ion s t age iss to red in the p rod uc t mode l . As we l l a s the p ro duc t m ode l , the"des ign fun c t ion , " " cu t t ing func t ion , " and "v i r tua l a s semblingfunc t ion ' a re in t roduced . By us ing the des ign func t ion , anytype o f s h ip ' s s t ruc tu re can be des igned , and by us ing thecu t t ing func t ion , the des ign o f a s h ip 's s t ruc tu re can be cu t in tos ma l le r e l emen ts . By us ing the v i r tua l a s s embl ing func t ion , as imula t ion o f the manufac tu re o f a s h ip ' s s t ruc tu re can beca r r i ed ou t .Key w ords : p r o d u ct m o d e l, C IM , C A D / C A M / C A E

I n t r o d u c t i o nL a r g e - s c a l e c o m p u t e r s y s t e m s h a v e b e e n d e v e l o p e di n o r d e r t o s u p p o r t d e s i g n a n d m a n u f a c t u r i n g a c -t i v i t i e s . I n t h e s h i p b u i l d i n g i n d u s t r y , c o m p u t e r s h a v eb e e n i n u s e s in c e t h e 1 9 60 s, a n d m a n y c o m p u t e r

Address correspondence to: K . A o y a m aR e c e i v e d f o r p u b l i c a t i o n o n D e c . 1 0 , 1 9 9 6; a c c e p t e d o nJ u n e 1 6 , 1 9 9 7

s y s t e m s h a v e b e e n d e v e l o p e d t o s u p p o r t d e s i g n a n dm a n u f a c t u r e .

T h e e n v i r o n m e n t o f d es i g n a n d m a n u f a c t u r e i s c o n -s t a n tl y c h a n g in g , a n d m a n u f a c t u r i n g i n d u s t r i e s h a v e t oa d a p t t o t h e s e c h a n g e s . S o n e w s y s te m s w h i c h s u p p o r td e s i g n a n d m a n u f a c t u r i n g a c ti v it ie s m u s t b e d e v e l o p e d .A r e l a ti v e l y n e w c o n c e p t in m a n u f a c t u r i n g s y s t e m s isp r o p o s e d h e r e . T h i s is a " C o m p u t e r I n t e g r a t e d M a n u -f a c t u r i n g s y s t e m " ( C I M ) , w h i c h r e p r e s e n t s a n e w g e n -e r a t i o n i n s u c h s y s t e m s ( F i g . 1 ) . V a r i o u s m a n u f a c t u r i n gi n d u s tr i e s h a v e m a d e e f f o r t s to d e v e l o p C I M . I n t h es h i p b u i l d i n g i n d u s t r y , w h i c h i s a m a t u r e i n d u s t r y , v a r i -o u s p o s s i b i l i t i e s h a v e a l r e a d y b e e n t r i e d o u t i n s e v e r a lc o m p a n i e s .

I n t h is p a p e r , t h e a u t h o r s p a y p a r t i c u l a r a t t e n t i o nt o r e s e a r c h i n t o t h e d e v e l o p m e n t o f C I M i n s h i pb u i ld -ing ~-3 in t wo m a in a rea s .- - M o d e l i n g d e s i g n a n d m a n u f a c t u r i n g a c t i v i t i e s i n

s h i p b u i l d i n g . V a r i o u s a c t i v i t ie s a n d t a r g e t s a r e a n a -l y z e d a n d o r g a n i z e d i n a n a t t e m p t t o c l a ri f y w h i c hi n f o r m a t i o n s h o u l d b e g e n e r a t e d , t ra n s m i t t e d , a n dp r o c e s s e d b y a c o m p u t e r .

- - D e v e l o p i n g a p r o t o t y p e s y s te m f o r C I M i n s h ip -b u i ld i n g . A p r o t o t y p e s y s t e m o f C I M i n sh i p b u i ld i n gi s d e v e l o p e d b a s e d o n s h i p b u i l d i n g m o d e l s . S m a l l -t a l k , w h i c h i s a n o b j e c t o r i e n t e d l a n g u a g e , i s u s e d t od e v e l o p t h i s s y s t e m .

D e s i g n a n d m a n u f a c t u r in g s y st e m s i n s h i p b u i l d i n gProblems in developing CIMI n o r d e r t o d e v e l o p C I M , i t i s n e c e s s a r y t h a ti n f o r m a t i o n o n d e s i g n a n d m a n u f a c t u r i n g a c t i v i t i e si s i n t e g r a t e d . H o w e v e r , a p r e l i m i n a r y c o n s i d e r a t i o no f i n t e g r a ti o n s h o w s t h a t t h e r e a r e s e v e r a l p r o b l e m si n th e c u r r e n t s y s t e m t h r e e o f w h i c h a r e o u t l i n e db e l o w .


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K. Aoya ma and T. Nomoto: Models for CIM in shipbuilding 149

Fig. 1. Co mpu ter integrated m anufacturing by produ ct model

- - I so la ted in format ion . Since many ind ividua l sys temssupport individual aspects of business, the informa-tion generated is isolated.

- - The administration and transmission of essential in-formation is inadequate. Since the transmission ofin format ion depends on human in te rven t ion , essen-tial information is not always available.

- - The genera t ion o f in fo rmat ion i s more impor tan tthan i ts transmission. In current systems, designersthink that the gen eration of effective informatio n ismore impor tan t than i t s subsequen t t ransmiss ion .

Modeling for design and manufacturing systemsAt the various design and manufacturing stages, infor-mat ion i s genera ted , t ransmit ted , and p rocessed . Suchinformat ion f rom manufac tu r ing sys tems i s o f fourtypes.- - In format ion on manufac tu r ing ta rge ts (des ign re -

quirements, design specif ications, engineering draw-ings , p roduct per fo rmance , p roduct ion p rocesses ,etc.).

- - In format ion on manufac tu r ing con t ro l (p roduct ionplanning, production results, stock, orders, ship-ments, etc.) .

- - I n f o r m a t io n o n m a n u f ac tu rin g p r o c esse s ( d es ignprocedures , p roduct ion p repara t ion p rocedures ,etc.).

- - In format ion on manufac tu r ing resources and en-v i ronment ( techno log ica l da ta , p roduct ion equ ip-ment, etc.) .

I t is thought that integration of the generatio n o fnecessary information for production activit ies and thetransmission and adm inistration of such information isv i ta l in the deve lopm ent o f CIM. Therefore , p roductsand manufac tu r ing ac t iv i t ies have been m odeled a longthe following lines.

- - Model ing the p roduct . Express ion o f p roduct on acomputer .

- - Model ing manufac tu r ing p rocesses . Express ion o fmanufacturing activit ies on a computer .

- - Model ing the manufac tu r ing env i ronment . Expres-sion of the manufac turing environm ent, such as thefac to ry , the p roduct ion equ ipment , and the workers ,on a computer .

Characteristics of the design processThe design stages in manufacturing can be classif ied asfollows:Conce p t des ign ~ Elem entary des ign ~ Deta i leddesign --~ Prod uction design

Informat ion on a p roduct i s genera ted a t each des ignstage, and the information generated at each stage isdifferent. Therefore, i t is thought that design activit iescan be examined in the following way.- - The des igner conf igures a p roduct f rom the requ i re -

ments specif ied at each design stage.- - The des igner then genera tes enough in format ion on

a p roduct fo r manufac tu re to take p lace .These design character ist ics also apply to ship-

building design. Design information is generatedat each stage of the activity . This information mustthen be separa ted in to des ign requ i rements and des igntargets. Here, the design process is expressed on thecomputer .

The designer 's activit ies are then separated into thegenera t ion o f p roduct in fo rmat ion and the p rocess ing o fthat information at each design stage (elementary de-sign, structural design, detailed design, and productiondesign) . The design process i tself is then m ode led o n thecomp uter as a design p rocess model. F igure 2 shows themodeling of design processes in shipbuilding.Elem entary des ign . In the e lemen tary des ign s tage ,the main p urpos e is the selection of the principal dimen-s ions and the des ign o f the genera l a r rangement o fthe ship. At this stage, the target for the design is thewhole product ( i .e . the whole ship) . The principal di-mens ions and l ine offsets, and the arrang eme nt of thecompa r tments a re considered . A hu ll fo rm and a s t ruc-tural style are also decided to satisfy the customer 'srequ i rements .Structural design. The main purp ose of the structuraldesign is a consideration of the structures which willsa t is fy the s ty le requ i rements agreed a t the e lem entarydesign stage. That is, the internal structures of the shipare designed to give maximum strength for that style.Many s t ruc tu ra l mem bers a re des igned a t th is s tage, and


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150 K. Aoyama and T. Nomoto: Models for CIM in shipbuilding

Fig. 2. Model of the design process and product model

the designer checks the strength of the main structureswhich are composed of those members.Detai led design and production design. In the de-tailed design and production design stages, details of thestrength and ease of productivity of the structural mem-bers are considered. To do this, a great deal of detailedinformation must be generated.

Produ ct mod el in shipbuildingMany models are needed to support the various designactivities in which a computers is used. If these modelsare entirely independent from each other, handlingthem becomes difficult. So the concept of the integrat edmodel is very important. However, the integratedmodel is not clearly defined, so this aspect is nowconsidered.

The final shape of a product is not an adequate de-scription of that product for the computer. It is neces-sary to input a lot of information which does notexplicitly appear in the overall shape of the product.Tha t information must be considered in the design pro-cess, and the model which describes all this informat ionis a "product model".4 If the product model in ship-building is defined and the product can be expressed onthe computer, than all the product information can beused at the various design stages.

This paper reports on the development of a CIMsystem for shipbuilding. This system is called SODAS(System Of Design and Assembling for Shipbuilding).It was developed using Smalltalk, which is an object-

oriented language. In SODAS, several objects are de-fined for the product model in shipbuilding: These are aparts object, a connection object, a room object, a unitobject, a module object, and so on.

Targets o f designTwo of a ship's functions are carrying cargo and keepingof float. In order to secure the loading capacity andbuoyancy, various closed spaces (compartments, holds,and tanks) are designed within a ship. From the viewpoint of "Space", it is possible to divide the structuralparts of a ship into these groups.Compar tments , holds, and tanks. The external formof a ship is composed of a side shell, a deck plate, and abottom shell. The closed spaces are generated in theship by these members. The closed space of the ship'shull is divided~-into several compartment s, holds, andtanks by several partition plate members.Interna l structures. The primary structural members(primary plate m embers and primary section members)are designed to keep the shapes of the closed spaces ina ship. Small plate members and section members (sec-ondary members) are designed to reinforce primarystructural members.Structural members and parts. There are two types ofstructural members. One is a plate parts member, andthe othe r is a section member. One memb er is joined toanother by welding. The structural members are de-


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K. Aov ama and T. Nom oto: Models for CIM in shinbuildin~ 151

Fig. 3. Room object

s igne d a t t he s t r uc tu r a l de s ign s ta ge . A t t he p r oduc t ions tage , the ta rg e t of cut t ing , bending , and assem bl ing isno t f o r s t r uc tu r a l m e m be r s bu t f o r pa r t s .Ro om (compartments, holds, and tanks)Thi s pa pe r c ons ide r s t hose spa c e s wh ic h a r e c om pa r t -men ts o r tanks in the des ign. This type of space i sde f ine d a s a r oom , a nd th i s c onc e p t i s u se d to suppor tthe e l e m e n ta r y de s ign . " R oom " i s a ge ne r i c t e r m f o ra c lo se d spa c e suc h a s a c om pa r tm e n t , ho ld , o r t a nkin a ship.

B y m ode l ing the de s ign o f a sh ip ' s s t r uc tu r e on thede s ign o f a r oom ( se e s e c t ion on De s ign f unc t ion f o rspa c e s) , t he ge ne r a t ion o f i n f o r m a t io n a bou t p l a t em e m be r s a nd we lde d jo in t s a r e r e l a t e d . S o a de s igne rc a n unde r s t a nd the m a ny in f lue nc e s wh ic h a f f e c t t hejo in ing o f p l a t e s i n to t he i r c o r r e c t sha pe .

Whe n the e xp r e s s ion o f a r oom i s i npu t on the c om -pu te r , i t i s im po r t a n t t o ha ve a de s ign m od e l wh ic h use sthe c onc e p t o f a r oom .- - The vo lu m e o f a r oo m c a n be c a lc u l a t ed .- - The sha pe o f a pa r t i t i on p l a t e c a n be de s igne d wi th

no inc ons i s te nc e s .In th is work the shape of a room is de f ined by a so l id

m ode l wh ic h i s t he bounda r y r e p r e se n ta t ion ( B - R e ps ) .The da t a o f a w inge d- e dge s t r uc tu r e c a n be ge ne r a t e df r om the sha pe da t a o f a p l a t e m e m be r a nd the ge o -

m e t r i c a l c onne c t ive r e l a t i on o f p l a t e m e m be r s . I n t h i swor k , t he sha pe o f a r oom i s ge ne r a t e d f r om the in f o r -m a t ion on p l a t e pa r t s a nd pa r t s c onne c t ions F igu r e 3shows a f low d ia g r a m o f t he ge n e r a t ion o f t he r oom .R oo m ob je c t . A r oom ob je c t i s de f ine d a s i n f o r m a t iona bou t a c om pa r tm e n t a nd va r ious t a nks . The sha pe o fa room objec t i s expressed as a so l id mode l which en-c lose s s e ve r a l pa r t s m e m be r s . Th i s ob je c t i s ge ne r a t e d( de s igne d ) by the de s ign f unc t ion f o r spa c e s.

Fig. 4. Unit object

Unit (structural unit o f ship structures)Eve r y sh ip ha s he r own s t r uc tu r a l s ty l e . Howe ve r ,the re a re a lo t of co mm on par t ia l s t ruc tu res in a sh ip .I t i s poss ib le to def ine a common par t ia l s t ruc ture asa " s t ruc tura l uni t . " I t i s thought tha t the des ign ofsh ip ' s s t r uc tu r e s c a n be e xp r e s se d a s t he de s ign o f ac om b ina t ion o f s tr uc tu r a l un it s . S uc h a s t r uc tu r a l un i ti s ca l led a "Uni t" in th is paper . A des igner can des ignthe sh ip ' s s t r uc tu r e by c ons ide r ing a c om bina t io n o fun i t s, a nd c a n ha nd le e a s i l y m a ny pa r t s m e m b e r s b yuni t .Un i t ob j e c t . A un i t ob j e c t i s de f ine d a s i n f o r m a t ion onpr im a r y a nd se c onda r y in t e r na l s t r uc tu r e s . Th i s ob je c t


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152 K. Ao yam a and T. Nom oto: Models for CIM in shipbuilding

Fig. 5. Module object

ha s som e pa r t s ob j e c t s , a nd i s ge ne r a t e d ( de s igne d ) bythe des ign func t ion for in te rna l s t ruc tures . In th is paper ,thre e types of uni t a re def ined. F igure 4 shows a p la teuni t and a sec t ion uni t .B ox un i t . A bo x un i t is de f ine d by som e p l a t e pa r t sm e m b e r s . A c lo se d spac e c a n be e x t r a c t e d a s a r oom bythe p l a t e pa r t s m e m be r s o f wh ic h i t i s c om pose d . Thebigges t box uni t i s the ship ' s hul l . The box uni t of theship ' s hul l i s composed of a s ide she l l , a deck pla te , anda bo t tom she l l .P la te unit . A pla te uni t i s an in te rna l s t ruc ture whichsuppor t s t he de s igne d spa c e . A p l a t e un i t c a n be de -s igne d by f o llowing the de s ign pa r a m e te r s ( t he pos i t i onof a s t ru t , the de pth of a s t ru t or a r ing , e tc . ) . Some par tsm e m be r s a r e ge ne r a t e d , a nd in t e r na l s t r uc tu r e s o f va r i-ous sha pe s a r e de s igne d . The se pa r t s m e m be r s a r es tored by th is uni t .Sec t io n uni t . A sec t ion uni t is a se t of severa l sec t ionpa r t s m e m be r s . Th i s un i t i s de s igne d o f p l a t e pa r t s

m e m be r s t o i nc r e a se t he be nd ing s t r e ng th o f e a c h p l a t epa r t s m e m be r .

Mod ule (intermediate product)P r odu c t ion a c t iv i ti e s a r e c om p ose d o f a c om bi na t ion o fva r ious p r oduc t ion s t a ge s . An in t e r m e d ia t e p r oduc t i sa s se m ble d a t e a c h p r oduc t ion s t a ge , a nd th is p r oduc t i sc a r r i e d to t h~ f o llowing p r oduc t ion s t a ge . The r e f o r e ,p r odu c t ion a c t iv i t i es c a n be e xp r e s se d a s a " flow o fin t e r m e d ia t e p r oduc t s . " I n t h i s pa pe r , " M odu le " i s de -f ine d a s a n in t e r m e d ia t e p r oduc t wh ic h i s t he t a r ge t o fa p r oduc t ion a c t iv i ty . A p r oduc t ion p l a nne r c a n usea m odu le a s a un i t i n t he a dm in i s t r a t i on o f p r oduc t io nin f o r m a t ion .

A m odu le i s de f ine d as a se t of pa r ts to exp ress anin t e r m e d ia t e p r oduc t wh ic h i s t he c ons t r uc t ion un i t a te a c h p r oduc t i on s t a ge . A da t a s t r uc tu r e o f t he m od u le i sexpressed as a h ie ra rchica l s t ruc ture , shown in F ig . 5 .The m odu le o f t he l owe s t l a ye r i s c om p ose d o f one pa r t .T h e m o d u l e r e l at e s t o t h e m o d u l e c o n s t r u c t io n m e t h o dof the shipbui ld ing indust ry .


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K. Aoy ama and T. Nom oto: Models for CIM in shipbuilding 153c om pu te r . S ha pe da t a , c onne c t ion da t a , a t t r i bu t e da t a ,a nd so on a r e de sc r ibe d in t he i n f o r m a t ion on a pa r t sm e m b e r .

Fig. 6. Th e shape o f a parts ob ject, a A plate parts objec t, b Asection parts ob ject

Par ts objec t . A par ts objec t i s de f ined as info rma t ionon a pa r t s m e m be r , t he sha pe o f a pa r t s m e m b e r i se xp r e s se d by a su r f a c e m ode l , a nd the t h i c kne ss a ndm a te r i a l a r e de sc r ibe d a s a t t r i bu t e da t a . The pa r t s ob -jec t i s s tored in the uni t objec t . A des igner can a rbi -t r a r i l y e x t r a c t t he de s igne d pa r t s ob j e c t f r om the un i tob je c t . The r e f o r e , pa r t s i n f o r m a t ion c a n be t a ke n ou td i r e c t ly a nd c ha nge d i f ne ce s sa r y . S inc e the sha pe s o f ap l a t e pa r t s m e m be r a nd a s e c t ion pa r t s m e m be r a r ec ha r a c t e ri s t i c , ob j e c t s o f t he m a r e de f ine d ind iv idua l ly .F igu r e 6 shows a r e p r e se n ta t io n o f t he sha pe o f ea c hpar ts objec t .P l a t e par t s . The sha pe o f a p l a t e pa rt s m e m be r i s e x -p r e s se d by a su r f a c e m ode l i n t h r e e - d im e ns iona l spa c e ,and pla te th ickness i s d is regarded. This shape is de -sc r ibed by severa l ve r t ices and severa l edges .S e c t ion pa r t s. The we b sha pe o f a s e c t ion pa r t s m e m -be r i s e xp r e s se d by a su r fa c e m ode l . A se c t ion f o r m i sde sc r ibe d by a t t r i bu t e da t a . T he sha pe o f t h is ob je c t ise xp r e s se d by swe e p ing a s e c t ion f o r m a long a we bsha pe .

Fig. 7. Conn ection object

Connective relation between parts membersA c o nne c t ive r e l a t ion be twe e n pa r t s m e m b e r s i s de -f ine d as a " c onne c t ion ob je c t . " I n f o r m a t io n on the l oc a -t i on o f a c onne c t i on i s de sc r ibe d b y a w i r e f r a m e m od e l ,a nd the two pa r t s ob j e c t s wh ic h a r e j o ine d to e a c h o the ra r e de sc r ibe d in t h i s ob je c t . M or e ove r , t h i s c onne c t ionob je c t i s de sc r ibe d in t he se two pa r t s ob j e c t s a s i n f o r m a -t ion on the c onne c t ive r e la t i on . F igu r e 7 shows the da t as t r uc tu r e o f a c onne c t ion ob je c t .

A t t he l e ve l o f a ge om e t r i c a l e l e m e n t , we c a n r e c og-n iz e t he i n f o r m a t ion on the r e l a t i on o f t he se e l e m e n t s .A ge om e t r i c a l e l e m e n t i s a ve r t e x , a n e dge , o r a l oop ,which d ef ines the shape of par ts . The re la t ions of a l lge om e t r i c a l e l e m e n t s o f j o in t e d p a r t s sha pe s a r e de -sc r ibe d by the i n f o r m a t ion on the c onne c t ive r e l a t i on .

M odu le ob je c t. A m od u le ob je c t i s de f ine d a s i n f o r -m a t i o n a b o u t i n t e r m e d i a t e p r o d u c t s a t t h e p r o d u c t i o ns tage . This objec t has some par ts objec ts , and is gener -a t e d ( de s igne d ) by the c u t t i ng func t ion a nd the v i r tua la s se m bl ing f unc t ion .

Parts member sI n f o r m a t ion on p l a t e pa r t s m e m be r s a nd se c t ion pa r t sm e m be r s i s t he ba s i c e l e m e n t o f sh ip s t r uc tu r e on a

C onn e c t ion ob jec t . I n f o r m a t ion on a c onne c t ion be -twe e n two pa r t s m e m be r s i s de f ine d a s a " C onne c t ionObje c t . " Th i s i n f o r m a t ion i s l a t e r c onve r t e d in to we ld -l i ne i n f o r m a t ion .

Functio n for elementary design and structural designI n o r de r t o ge ne r a t e a nd s to r e i n f o r m a t ion on a p r odu c ta s t he p r oduc t m ode l a t t he e l e m e n ta r y de s ign a ndst ruc tura l des ign s tages , the des ign func t io n is de f ine d in


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154 K. Aoy ama and T. Nom oto: Models for CIM in shipbuilding- - The de s igne r i npu t s da t a o f a p l a ne wh ic h def ine the

su r f a c e o f a pa r t i t i on o f p l a te pa r t s . An e xa m ple o fthe se da t a a r e one po in t a nd a no r m a l ve c to r o f aplane .

- - The in t e r se c t ion o f t hi s p l a ne by the sha pe o f t hese lec ted room is ca lcula ted . This in te r sec t ion is de -sc r ibe d a s t he sha pe o f t he pa r t i t i on p l a t e pa r t s .- - The c on ne c t ive r e l a ti on ob je c t w i th t he p l a t e pa rt sob je c t wh ic h c om pose s t he box un i t a nd the pa r t i -t i on p l a t e pa r t s ob j e c t i s ge ne r a t e d a t t he s a m e t im e .

F i g . 8. Design function for space

S OD AS . The r e a r e two de sign f unc tions , t he se a r e " de -s ign func t ion f o r spa c e s" a nd " de s ign f unc t ion f o r i n t er -na l s t ruc tures . "Design function fo r spaces (rooms)On e c lo se d spa c e ( r o om ) i s d iv ide d in to s e ve r a l spa c es( r oom s) by the de s ign f unc t ion f o r spa c e s . C om pa r t -ments and tanks in a sh ip can be des igned us ing th isf unc t ion . I t i s t hough t t ha t t h i s f unc t ion c o r r e spo nds tothe e lementa ry des ign of a sh ip . S ince a des igner cane a s i ly c on f i r m the sha pe o f a r oom , he c a n unde r s t a ndthe va r ious i n f lue nc e s o f t he de s ign o f pa r t i t i on p l a t epar ts . A des ign suppor t sys tem, inc luding a few smal lf unc t ions, has be e n de ve lope d in S OD AS . F igu r e 8shows the f low of th is func t ion .Ge n e r a t io n o f ne w pa r t i t i on p l a t es . The in it i al r oom ,which is an in te rna l space in the hul l , can be ext rac tedf rom th e p la te par ts such as she l l p la tes and d eck pla tes .The sha pe o f t h is r oom i s de f ine d by a so lid m ode l . Theou t l i ne o f t he ge ne r a t ion o f ne w pa r t i t i on p l a t e s i sshown be low.- - A de s ign e r c a n de s ign se ve r a l pa r t i t i on p l a t e pa r t s in

a r oom . The sha pe s o f t hose p l a t e pa r t s c a n be t a ke nou t a c c o r d ing to t he sha pe o f t he r oom .

Ge n e r a t i on o f ne w r oom s . A de s igne r c a n de s ign se v-e r a l pa r t i t i on p l a t e s u s ing the a bove - m e n t ione d f unc -t i on . The f low o f t he ge ne r a t ion o f ne w r oom s f r ompa r t i t i on p l a t e s i s shown be low.- - S m a ll r oom s ( " c h i ld" r oom s) a re f o r m e d by c ons id -

e r ing the sha pe s o f the pa r t i t i on p l a t e pa r t s a nd thes h a p e o f t h e d i v i d ed r o o m ( " p a r e n t " r o o m ) . T h eshape of th is smal l room is de f ined by a so l id mode l .

- - The sha pe o f t he ne w sm al l r oom i s c he c ke d by us ingin f o r m a t io n on the sha pe o f t he d iv ide d r oom , thesha pe s o f p l a t e pa r t s ge ne r a t e d , a nd the c onn e c t iver e l a t i on ob je c t s ge ne r a t e d .

- - Ne w r oom s a r e ge ne r a t e d w i th a ne w sha pe , wh ic h isc he c ke d .

- - N e w b o x u n i t s a r e g e n e r a t e d . T h e n e w g e n e r a t e dpa r t i t i on p l a t e pa r t s a nd se ve r a l p l a t e pa r t s wh ic hm a ke the d iv ide d r oom a r e s to r e d in t h i s ne w boxunit .

The c onc e p t o f a wa ll . The sha pe o f a r oom i s e x -p r e s se d a s a po lyhe d r on , a nd the su r f a c e o f a r oomc or r e spon ds to t he p l a t e pa r t s. The p l a ne o f wh ic h th ispolyhedron is composed is ca l led a "wal l . " A wal l i s age om e t r i c a l c onc e p t w i thou t t h i c kne ss . The wa l l e x i s t sa s t he boun da r y be t we e n the p l a t e a nd the r oom . M or e -ove r , t he wa l l i s one se c t ion o f t he po lyhe d r on o f t her oo m a t t he s a m e t im e a s be ing the a r e a on the su r f a c eof the p la te par ts (F ig . 9) .

Design functibn for internal structuresThe de s ign f unc t ion f o r i n t e r na l s t r uc tu r e i s u se d tode s ign long i tud ina l s t r uc tu r a l m e m be r s a nd t r a nsve r ses t r uc tu r a l m e m b e r s t o r e in f o r c e p la t e m e m b e r s ( F ig .10 ) . The c onc e p t o f a pa r a m e t r i c de s ign i s i n t r oduc e dfor th is func t ion and i t can eas i ly des ign th is compl i -c a t e d s t r uc tu r e . Us ing th i s f unc t ion , t he p l a ne un i t ob -j e c t a nd the s e c t ion un i t ob j e c t a r e ge ne r a t e d a s t hein te rna l s t ruc ture s in a sh ip . Th e out l ine o f th is func t ionis g iven be low .De s ign ing the p l a ne un it . The p l a ne un i t i s a n in t e r na ls t r uc tu r e t o suppor t de s igne d inne r spa c e s . Va r ious


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Fig. 9. Room and wall

s h a p e s o f i n t e r n a l s t r u c t u r e s m u s t b e d e f in e d . T h e p l a n euni t i s des igned as fo l lows .- - T h e d e s i g n e r s el e c ts th e r o o m f o r w h i c h h e w a n t s t o

d e s i g n a n i n t e r n a l s t r u c t u r e .- - T h e d e s i g n e r i n pu t s a s m a n y d e si g n p a r a m e t e r s a s

a r e n e c e s s a r y t o d e f i n e t h e i n t e r n a l s t r u c t u r a l s h a p e .- - T h e e x t e r n a l s h a p e o f th e i n t e r n a l s t r u c t u r e i s d e -s i g n e d a u t o m a t i c a l l y u s i n g i n f o r m a t i o n a b o u t t h er o o m .

- - I n f o r m a t i o n o n th e c o n n e c t iv e r e la t i o n is g e n e r a t e da u t o m a t i c l l y .

- - T h e s h a p e o f t h e i n t e r n a l s t r u c t u r e i s d e f i n e d b y t h ed e s i g n p a r a m e t e r s p e c i f i e d . S e v e r a l o t h e r p a r t s , e . g .f a c e p l a t e p a r t s , b r a c k e t p a r t s , a n d s o o n , a r e d e -s igned.

- - T h e g e n e r a t e d p a r t s a r e s t o r e d i n t h e p l a t e u n i t.

Des ig ning the s ec t ion uni t . Th e sec t ion uni t is a s e t ofs e v e r a l s e c t i o n p a r t s . B e c a u s e a l a n d i n g l i n e i s n e c e s s a r yt o d e s i g n s e c t i o n p a r t s , t h e d e s i g n e r m u s t d e s i g n t h i sl in e , a n d t h e m o u n t i n g d i r e c t i o n a n d t h e t y p e o f s e c t i o np a r t s a r e n e c e s s a r y t o d e f i n e t h e s h a p e o f t h e p a r t s . T h esec t ion uni t i s des igned as fo l lows .- - T h e d e s i g n e r s e l e ct s t h e w a l l w h i c h h e w a n t s t o u se

t o d e s i g n a n i n t e r n a l s t r u c t u r e .- - T h e d e s i g n e r i n p u t s t h e d e s i g n p a r a m e t e r s w h i c h

a r e n e c e s s a r y t o d e f i n e a n i n t e r n a l s t r u c t u r e . F o re x a m p l e , o n e d e s i g n p a r a m e t e r i s t h e n u m b e r o fsec t ion par t s .

- - T h e l a n d i n g l i n e s o f th e s e c t i o n p a r t s a r e d e s i g n e do n t h e s e l e c t e d w a l l . T h e d e s i g n e r c a n i n p u t t h elanding l ines d i rec t ly .

- - T h e d e s i g n e r i n p u ts i n f o r m a t i o n o n e a c h s e c ti o np a r t . T h i s i n f o r m a t i o n c o n s i st s o f a m o u n t i n g d i r e c -t i o n , th e t y p e o f s e c ti o n p a r t s , a n d s o o n . T h e s h a p eo f t h e s e c t i o n p a r t s i s g e n e r a t e d .

- - I n f o r m a t i o n o n th e c o n n e c t iv e r e la t i o n is g e n e r a t e da u t o m a t i c a l l y .

Fig. 10. Design function for internal structure

Description of design information anddesign modificationI t i s be l i eved tha t des ign ac t iv i ty i s an ac t by which thei n t e n t i o n o f th e d e s i g n is d e s c r i b e d a c c o r d i n g t o t h ed e s ig n p a r a m e t e r s .

W h e n a d e s i g n i s f i n is h e d , w e c a n s e e o n l y t h e f i n a lf o r m o f t h e p r o d u c t , w e c a n n o t s e e t h e d e s i g n e r ' s i n t e n -t i o n f o r t h a t p r o d u c t . H o w e v e r , t h e d e s i g n e r ' s i n t e n t i o ni s ve ry impor tant , and so i t i s e s sent i a l to s tore i t a s pa r to f th e d e s i g n i n f o r m a t i o n o n t h e p r o d u c t m o d e l .

I n t h i s p a p e r , t h e d e s i g n p r o c e s s e s a n d t h e d e s i g np a r a m e t e r s a r e c o n s i d e r e d t o e x p r e s s t h e d e s ig n proce-


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156 K. Aoy ama and T. Nom oto: Models for CIM in shipbuildingdur e i n o r de r t o de sc r ibe t he de s ign in f o r m a t ion on thep r o d u c t m o d e l .

Description of the design processR e s t r i c t i on by s t r uc tu r e . B e f o r e t he de s ign p r oc e s s i sde sc r ibe d , i t i s im por t a n t t o r e c ogn iz e t he r e l a t i ons be -twe e n r oom s a nd un i t s . The r e a r e c ha r a c t e r is t i c r es t r ic -t i ons i n bo th the r oom a nd the un i t .- - Th e sha pe o f a sm a ll r oom ( i. e. a c h i ld r oom ) wi th i n

a la rge room ( i . e . a pa rent room) is res t r ic ted by thesha pe o f the l a r ge r oom .

- - The e x t e r na l sha pe o f a n in t e r na l s t r uc tu r e i s ne ve rb igge r t ha n the sha pe o f t he r oom to wh ic h thein t e r na l s t r uc tu r e be longs .

The r e s t r i c ti on wh ic h i s im pos e d by the de s ign f low isuse d f o r t he de s ign f unc t ions ba se d on the c onc e p t s o fthe r oom a nd the un i t . I n t h i s pa pe r t he r e s t r i c t i on i sconsidered as fo l lows.- - T h e r e a r e t h e p a r e n t r o o m s a n d c h i l d r o o m s . T h e

c h i ld r oom s a r e de s igne d in s ide the pa r e n t r oom .The pa r e n t r oom r e s t r i c t s t he c h i ld r oom .

- - The un i t ( i n t e r na l s t r uc tu r e ) i n s ide the pa r e n t r oomis the chi ld room. I f the parent i s the room, theparent res t r ic ts the chi ldren .

I n t h is pa pe r , t he r e s t r i c t i on o f t he r e l a t i ons be twe e nparent and chi ld i s de f ined as a " res t r ic t ion by s t ruc-tu r e , " a nd the r e l a t i ons be twe e n pa r e n t a nd c h i ld e x -press the res t r ic t ions which exis ts in the des ign f low ofthe ship ' s s t ruc ture .H ie r a r c h ic a l da t a s t r uc tu r e. The de s ign f unc t ion f o rspa c e doe s no t a c tua l ly d iv ide the r oom sha pe . Theshape of the chi ld roo m is only ca lcula ted , and the or ig i -na l sha pe o f t he pa r e n t r oom i s s to r e d . The r e f o r e , bys to r ing a ll t he r oom s wh ic h a r e d iv ide d , t he h i e r a r c h ic a lda t a s t r uc tu r e o f t he r oom s i s ge ne r a t e d ( F ig . 11) . B yspe c i fy ing the r e l a t i on be twe e n the un i t a nd the r oom ,the h i e r a r c h ic a l da t a s t r uc tu r e s o f un it s a nd r oom s a r ea l so ge ne r a t e d .

I f t he r e l a ti ons be twe e n the pa r e n t s a nd c h i ld r e n o fa l l roo ms an d a l l uni ts a re expre ssed as h ie ra rchica l da tas t r uc tu re s , t he de s ign p r oc e s s c a n be s to r e d in t he p r od -uc t m ode l . F ina l ly , " the who le o f t he sh ip" i s e xp r e s se da s a " t r e e o f t he r oom s a nd the un i t s . "

Description Of design parametersR e s t r i c t i on by de s ign pa r a m e te r s . The r e f e r e nc e va luei s u se f u l f o r t he de sc r ip t ion o f a p r oduc t sha pe . Thedescr ip t ion by a re fe rence va lue i s ca l led a des ign pa-r a m e te r on the d r a wing she e t a nd in t he c om pu te ra ide d de s ign ( C AD) ( F ig . 12 ) . De s ign pa r a m e te r s be -

Fig. 11. Data structure of rooms

Fig. 12. Design param eters

c om e the ge om e t r i c a l r e s t r a in t s t o t he p r oduc t sha pe ?I n th i s pa pe r , t he r e s t r i c t i on o f t he p r od uc t sha pe by thede s ign pa r a m e te r s i s de f ine d a s " r e s t r i c t i on by de s ignp a r a m e t e r s . "D e s i g n e d i t or . I n S O D A S , t h e r o o m s h a p es a n d t h euni t shapes a re des igned us ing drawing tools (F ig . 13) .The se t o f t he se t oo l s is t he " de s ign e d i to r . " Th i s e d i to ri s two- d im e ns iona l , a n d the d r a wing a r e a o f t he e d i to r i sin a s e c t ion o f t he r oo m .

The f low o f de s ign by the de s ign e d i to r i s shownbe low.


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Hg. 13. Design tools for a plate unit

Description of the design procedureI n t h i s a pp r oa c h , t he de sc r ip t ion o f t he de s ign pa r a m -e te r s a nd the h i e r a r c h ic a l da t a s t r uc tu r e a r e u se d todescr ibe the des ign procedure (F ig . 14) . The des ign pa-r a m e te r s f o r a c h i ld r oom ( o r un i t ) a r e de sc r ibe d un de rp a r e n t r o o m . T h e r e f o r e t h e d e s ig n p a r a m e t e r s a r es to r e d w i th a h i e r a r c h ic a l r e l a t i onsh ip be twe e n r oom s .Th i s m e a ns tha t t he e n t i r e de s ign p r oc e dur e i sde sc r ibe d .

Fig. 14. Descriptio n of the design procedu re

- - The de s igne r s e le c t s t he box un i t wh ic h is t he t a r ge tfor the des ign for par t i t ion p la tes and in te rna l s t ruc-tures .

- - The d r a wing a r e a o f t he de s ign e d i to r i s e x t r a c t e df r om a r oom sha pe o f t he box un i t s e l e c t e d .

- - The de s ign e r d ra ws l i nes on the d r a wing p l a ne .- - The de s igne r s e t s t he pos i t i on o f e a c h l i ne u s ing the

de s ign pa r a m e te r s .- - The de s igne r i npu t s t he a t t r i bu t e s o f e a c h l i ne ( t he

l ines of a par t i t ion p la te , an in te rna l s t ruc tura lshape , e tc . ) .

- - Dr a wn l i ne s a r e c ha nge d to pa r t i t i on p l a t e pa r t s o rin t e r na l s t r uc tu r a l sha pe s .

The de s ign pa r a m e te r ob je c t is de f ine d to c on t r o l t hede sign . A l l i n f o r m a t ion o n the de s ign o f t he r oo m o run i t ( i . e . t he s e c t ion f o r m o f t he r oom , in f o r m a t ionabout l ines and ver t ices which change the p la te par ts ,r e f e r e nc e l i ne s , e t c . ) i s s a ve d by the de s ign pa r a m e te robjec t .

Design modificationsA designer can des ign a sh ip ' s s t ruc ture us ing thea bove - m e n t ione d de s ign f unc t ions ( F ig . 15 ) . I n o r de rtha t t he sys t e m c a n r e spon d to t he de m a nds o f t hede s igne r ' s m od i f i c a t ions , S ODAS inc o r po r a t e s a de -sc r ip t ion of these des ign func t ion s as a des ign process(Fig. 16).

I n t h i s a pp r oa c h , t he pa r e n t r oom c on t r o l s t he R e -s t r i c t i ons by de s ign pa r a m e te r s a s de s ign in f o r m a t ionon the c h i ld r oom ( o r un i t ) . The r e f o r e , one de m a nd o fthe de s ign m od i f i c a t ion is t o m od i f y the r e s t r i c ti ons byde s ign pa r a m e te r s f o r a pa r e n t r oom .M odi f i c a t ion o f a n in t e r na l s t r uc tu r e . The de s ign pa -r a m e te r s a r e de sc r ibe d in t he pa r e n t r oom . The de -s igne r c a n m od i f y the se pa r a m e te r s , a nd the i n t e r na ls t r uc tu r e i s t he n a u tom a t i c a l ly r e - de s igne d . Th i s p r o -cess of re -des ign is s imi la r to the process of des ign.M od i f i c a t ion o f a r oom . Wh e n a de s igne r wa n t s t om od i f y the sha pe o f a r oom wi th a c h i ld s t r uc tu r e ( ar oom wi th a n in t e r na l s t r uc tu r e ) , t he r e s t r i c t i on bys t ruc ture of the chi ld s t ruc ture wi l l be changed. S incede s ign in f o r m a t ion a bou t t he c h i ld s t r uc tu r e i s c on -t r o l l e d in t he pa r e n t r o om , the sha pe o f t he c h ild s t ruc -tu r e i s c ha nge d by us ing i t s own de s ign in f o r m a t ion .


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Fig. 15. Ex am ple o f a ship's structure

Fig. 16. Design modifications


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Fig. 17. Cutting function Fig. 19. Virtual assembling function

Whe n the c ha nge d r oom ha s c h i ld s t r uc tu r e , t he r e -de s ign o f t he c h i ld s t r uc tu r e i s a u tom a t i c a l ly p r oc e s se dby the de s ign p r oc e dur e de sc r ibe d a bove .

Fig. 18. Design m odule by cutting function

Functions for detailed design and production designI t i s im por t a n t t o ge ne r a t e m or e de t a i l e d in f o r m a t ionf o r t he p r oduc t ion s t a ge f r om in f o r m a t ion tha t i s ge ne r -a t e d a t t he e l e m e n ta r y de s ign s t a ge a nd the s t r uc tu r a ldes ign s tage . For example , i t i s necessa ry to def ine inde t a i l t he sha pe o f al l pa r t s e dge s a nd the t r e a tm e n t o fthe p l a t e pa r t s whe n the y m e e t a t a c o r ne r .

I n S ODAS , the v i r tua l a s se m bl ing f unc t ion i s i n t r o -duc e d to de f ine de t a i l ed in f o r m a t ion f o r t he p r oduc t ionde s ign . Th i s s e c t ion c ove r s t he c u t t i ng f unc t ion a nd thevir tua l assembl ing func t ion .Cutting functionThe pa r t s m e m be r s wh ic h a r e de s igne d by the de s ignf unc t ion i s no t show a ny d i f f e r e nc e s i n t h i c kne sso r s e c t ion f o r m . The de s igne d s t r uc tu r e m us t be de -c om pose d in to e r e c t ion m odu le s , m idd le m odu le s ( i . e .m idd le i n t e r m e d ia t e p r oduc t s ) o r sm a l l m odu le s( i . e . smal l in te rmedia te produc ts) .

I n a n a c tua l de sign , t he de s igne d pa r t s m e m be r s m us tbe d iv ide d in to sm a ll pa rt s . The r e a r e t h r e e r e a sons f o rthis division.


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160 K. Aoy ama and T. Nomoto: Models for CIM in shipbuildingTh e f l o w

(Fig. 17).of the cu t t ing funct ion i s shown below

Th e d es i g n e r pi ck s o u t a p ar t s m em b er .The des igner inputs the cu t t ing l ines on the par t sm e m b e r .

- - Th e s h ap e o f t h e p a r t s m em b e r i s d i v i d ed at t h ecut t ing l ine.- - Th e s h ap e o f t h e n ew p a rt s m em b e r i s g en e ra t ed .- - Th e a t t r i b u t e i n fo rm at i o n is co p i ed f ro m t h e d i v i d ed

p ar t s m em b er t o t h e n ew p a r t s m em b ers .- - Th e co n n ec t i v e r e l a t io n o b j ec t i s g en e ra t ed b e t ween

t h e t wo n ewl y g en e ra t ed p a r t s m em b ers .- - Th e co n n ec t i v e r e la t i o n o b jec t o f t h e d i v i d ed pa r t s

me mb er i s d iv ided in the same way as the d iv i s ion oft h e p a r t s m em b er .

This funct ion can be used n ot on ly for the d iv i s ion ofa par t s member , bu t a l so for the d iv i s ion of a module .When a module i s d iv ided , i t i s t reated as thoughthe target of the d iv i s ion i s a s t ructure which cons i s t sof several par t s mem bers . This s t ructure m ight be as t ru c t u re o f t h e i n t e rm ed i a t e p ro d u c t wh i ch m u s t b ediv ided once, o r i t might be the en t i re des igned s t ruc-ture (Fig. 18).

Fig. 20. Detailed shape of parts

1 . To show di f ferences in p la te th ickness and sect ionfo rm .2 . To gene rate subdiv i s ions of s t ructures in the mod ulecons t ruct ion .

3 . To bu y s teel p la tes and sect ions f rom the s teelworks .The f i rs t po in t i s impor tan t a t the s t ructural des ign

s tage, and the second and th i rd poin t s are used a t thedeta i led des ign s tage and the product ion des ign s tage,r e s p ect i ve l y . Ho wev er , t h e co n cep t o f t h e g en e ra t i o n o finfor ma t ion abou t par t s i s the sam e at a l l st ages . In th i spaper , th i s d iv i s ion of par t s members i s def ined as thecut t ing funct ion . This funct ion corresponds to the de-ta i l ed des ign of par t s.

Virtual assembling functionThe s t ructure d iv ided by the cu t t ing funct ion i s a par t i a ls t ructure which was des igned by a des igner , and infor-m a t i o n ab o u t i t s p ar t s i s n o t en o u g h fo r t h e p ro d u c t i o ns t ag e . Th ere fo re , S ODAS co n t a i n s a "v i r t u a l a s s em -bl ing funct ion ."The v i r tual assembl ing funct ion i s a funct ion thatenables the des igner and the scheduler to def ine theas s em b l y o rd e r b y p i ck i n g o u t each p a r t f ro m t h e s t ru c -t u re wh i ch h as b een d es i g n ed b y t h e cu t t i n gfunct ion . In o ther words , th i s funct ion i s for processp lanning in sh ipbui ld ing . The des igner can input in for-m a t i o n o n p ro d u c t i o n u s i n g t hi s fu n ct i o n . F o r ex am p l e ,the se lect ion of a weld ing process , a weld ing condi t ion ,a deta i l o f the shape of an edge, or the value of ex tend-ing cer ta in par t s can be cons idered .

Mo reov er , i f the v i r tual assembl ing funct ion has h igh-level def in i t ion , i t is poss ib le to have a sys tem w hich cancheck the in ter ference between a f i l l e t weld which hasa l r ead y b een d o n e an d t h e co rn e r o f t h e f l o o r p l a t emember which i s being inser ted . This sys tem suppor t sthe product ion des ign by which the cu tout i s appl ied tot h e f l o o r p l a t e m em b e r . Th e d e t a i l ed s h ap es o f t he p ro -d u c t i o n p a r t s a r e d es i g n ed f ro m i n fo rm at i o n ab o u t t h edes igned s t ructure us ing th is funct ion (F ig. 19).Designing the detailed shapes of partsI t was s h o wn t h a t i n fo rm at i o n ab o u t t h e d e t a i l ed s h ap eso f p a r t s fo r p ro d u c t i o n can eas i ly b e o b t a i n ed b y u s i n g


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K. Aoy ama and T. Nomoto: Models for CIM in shipbuilding 161

Fig. 21. Product definition spiral and application systems

the v i r tual assembl ing funct ion . H owe ver , i t is necessaryt o g en e ra t e i n fo rm at i o n ab o u t t h es e d e t a il ed s h ap esbefore they are f i rs t cu t a t the product ion s tage. F igure2 0 s h o ws h o w i n fo rm at i o n ab o u t t h e d e t a i l ed s h ap es o fpar t s i s generated .

In o rd e r t o g en e ra t e d e t a i l ed i n fo rm at i o n ab o u t p a r ts ,the des igner has to se lect a lo t o f deta i led informat ionsuch as deta i l s o f shape, d eta i l s o f bevel ing , the value ofa groove, the value of ex tendin g par t s , and so on . In thes t ru c tu ra l d es i gn o f S ODA S , t h e s h ap es o f p a rt s m em -bers are expressed as a surface model . However , i t i sm o re ad v an t ag eo u s t o ex p ress t h e s h ap es o f t h es e p a r tsas a so l id model in the product ion des ign . For ins tance,i t i s conv enien t to express the shape s of par t s as so l idm o d e l s o t h a t we can u s e t h i s i n fo rm at i o n t o g en e ra t ed a t a fo r t h e NC cu t t in g m ach i n e .

S ince p la te th ickness i s descr ibed as a t t r ibu te datain SODAS, th i s th ickness has to be processed . I t i stherefore necessary to develop a funct ion which wi l lchange a surface model to a so l id model . In order tod ec i d e o n t h e d e t a i l ed g eo m et r i c d a t a o f an y p a r t , it isnecessary to cons ider the inf luence of a l l the pa ram etersof ad jacent par t s (especia l ly the th ickness of an ad jacentp la te) .

Wh en a l l t h es e p rep a ra t i o n s h av e b een m ad e , t h ed es i g n e r o n l y h as t o a r r an g e t h e cu t t i n g d a t a fo r NC .

Tha t i s , the des igner mus t speci fy which i s the nes t ingbr idge data , the cu t t ing order , the p ierc ing data , and soo n , an d t h en s t a r t th e cu t t i n g pro ces s o n t h e co m p u t e r .

Product definition spiral and simulation of designTh i s p ap e r h as co n s i d e red t h e n a t u re o f a p ro d u c tm o d e l fo r s h i p b u i l d i n g an d wh a t fu n c t i o n s a r e n eed edt o g en e ra t e t h a t p ro d u c t m o d e l . Th e g ro wt h p ro ces s o ft h e p ro d u c t m o d e l fo r s h ip b u i l d in g t h ro u g h t h e e l em en -tary des ign s tage to the deta i led des ign s tage i s ex-pressed in the product def in i t ion sp i ra l . This sp i ra lshows the des ign funct ion , the cu t t ing funct ion , and thevi r tual assembl ing funct ion , which are a l l necessary forthe product model to be developed in suff ic ien t deta i l(Fig. 21).

We can u n d er s t an d t h e r e l a t i o n b e t ween t h e p ro d u c tdef in i t ion spi ra l and the a ppl icat ion sys tems , bu t usual lyi t i s d i f f icu l t to judge whe ther the in form at ion we ha ve i sthe bes t for des ign or p lanning in the produ ct def in i t ionsys tem wi thout the appl icat ion sys tems .

Wi t h S ODAS , we can d es i g n a g en e ra l a r r an g em en twi th the des ign funct ion for space, and we can des ign ash ip 's s t ructure wi th the des ign funct ion for in ternals t ructures . The t ransverse r ing members , the longi tudi -


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162 K. Aoyama and T. Nomoto: Models for CIM in shipbuildingnal members, and the small structural members are gen-erat ed by this function. The system can respond quicklyto a designers demands.

We can calculate the capacity of tanks, and the weightand center of gravity of any structure very easily, andinformation about the connective relation is generatedautomatically. Information on the position and lengthof the connected line is easily accessed by using theconnection information.

Conc lus i on

This paper has considered the product model in ship-building which integrates all the available informationabout design and manufac turing activities. It also showsa proto type CIM system in shipbuilding.

The produc t model is represented by objects. A roomobject, a unit object, a module object, a parts object, anda connection object are defined in this prototype sys-tem, and several functions for generating the productmodel are included. These are a design function forspaces, a design function for internal structures, a cut-ting function, and a virtual assembling function.

Any type of ship can be designed by the design func-tion. Information on compartments, holds, and tanks isgenerated as room objects by the design function forspaces and various internal structures are generatedas unit objects in the room by the design function forinternal structures. These design functions supportthe elementary design and the structural design inshipbuilding. The parts objects generated contain infor-

mation on the connective relation as a connectionobject.The designer can divide the designed structure intosmall pieces (parts) using the cutting function, and thepieces can be assembled into a module by the virtualassembling function. This module is defined as the mod-ule object. These functions are useful in designing thedetailed shapes of parts and in production planning inshipbuilding.

This paper also introduced the product definitionspiral. This spiral expresses the flow of the generationof the product model in shipbuilding.

Re f e r e n c e s1 . N o m o t o T , A o y a m a K ( 19 9 2) S h i p d e f i n it i o n s y s te m i n c o m p u t e rin t eg r a t ed des ign and manuf ac tu r ing . I n : Vie r i a C B , M ar t ins P

( e d s) C o m p u t e r a p p l i c a t io n s i n t h e A u t o m a t i o n o f sh i p y a r do p e r a t i o n s a n d s h i p d e s i g n V I I . E l s e v i e r , A m s t e r d a m , p p 1 7 7 -18 52 . N o m o t o T , A o y a m a K , H a r i y a n t o ( 1 9 94 ) A n i m p l e m e n t a t i o n o f ap r o d u c t d e f i n it i o n sy s t e m i n c o m p u t e r i n t e g r a t e d d e s i g n a n d m a n u -f a c tu r i ng . 8 t h I n t e r n a t io n a l C o n f e r e n c e o n C o m p u t e r A p p l i c a t io n sin Shipbui lding, vol 1. pp 19-333 . N o m o t o T , A o y a m a K ( 1 9 95 ) P r o d u c t m o d e l i n g in C I M f o r sh ip -bu i ld ing and i t s app l i ca t ion f o r p r oduc t ion p l ann ing . I n t e r na t iona lSympos ium on P r ac t i ca l Des ign o f Sh ips and M obi l e Uni t s , pp1389-13984 . K i m u r a F ( 19 9 2) N e w d i r e c t i o n s o f C A D / C A M r e s e a r c h a n d d e -v e l o p m e n t f o r C I M . P r o c e e d i n g s I n t e r n a t i o n a l C I M S y m p o s i u m1992, pp 1-205 . Sar a T , Kim ur a F , Suzuk i H e t a l ( 1985) Des ign ing mach ine as s em-b ly s t r uc tu r e us ing geom et r i c cons t ra in t s i n p r oduc t m odel l i ng .Ann C I R P 34 :169- 172


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Information Models and Functions for CIM in Shipbuilding

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