Analiza izrade ukrijepljenih panela na proizvodnoj liniji

Ovaj se rad bavi problematikom izvedbe panela u brodogradilištu „Uljanik“ u Puli. Obuhvaća kratku analizu gradnje jednog RoRo broda, gradnja 475 iz tekuće proizvodnje brodogradilišta, po panelima, te detaljan opis taktova izrade koja se uspoređuju s klasičnom ručno mehaniziranom izradom. Na kraju se pokušavalo dati procjenu rada i smjernice za efikasniji rad panel linije. Korišteni podaci su prikupljeni većinom vizualnim praćenjem rada panel linije i kratkim razgovorima sa zaposlenicima tehnološkog ureda i radionice tijekom trodnevnog boravka u brodogradilištu

IMPROVABILITY OF THE FABRICATION LINE IN A SHIPYARD

The ship production process is a complex manufacturing system involving numerous working stations mutually interconnected by transport devices and buffers. Such a production system can be efficiently modeled using the stochastic system approach and Markov chains. Once formulated, the mathematical model enables analysis of the governing production system properties like the production rate, work-in-process, and probabilities of machine blockage and starvation that govern the production system bottleneck identification and its continuous improvement. Although the continuous improvement of the production system is a well-known issue, it is usually based on managerial intuition or more complex discrete event simulation yielding sub-optimal results. Therefore, a semi-analytical procedure for the improvability analysis using the Markov chain framework is presented in this paper in the case of the shipyard’s fabrication lines. Potential benefits for the shipyards are pointed out as the main gain of the improvability analysis

The Estimation of the Production Time for Steel Hull Elements Using the Finite State Method

The steel hull process of a shipyard transforms steel plates and profiles into elements needed to build the ship hull and superstructure. The production time for these elements is the basic input to schedule the whole shipbuilding process. Therefore, it is important to implement time estimation approaches based on production system engineering. In this study, the recently developed finite state method for serial and splitting lines is employed to describe the steel hull process of a shipyard semi-analytically. Two typical ship sections are chosen to estimate the corresponding key performance indicators as the production rate, the work in process, and probabilities of starvation and blockade. The production time is estimated based on the production rate and the cycle time. These results are compared to the results obtained through a simulation approach using the software tool Enterprise Dynamics. The conclusion highlights the advantages and disadvantages of both approaches

Application of Semi-Analytical Methods in Production Systems Engineering: Serial Lines

Production lines can be designed by an analytical, semi-analytical, or numerical approach. This paper gives a brief introduction to the analytical approach of a single buffer line, the aggregation method, and the analytical approach of a multi-buffer line. An automotive paint shop production system will be used as a figurative example to compare the aggregation method and the recently developed analytical approach for a multi-buffer line. A discussion at the end will show the advantages and disadvantages of the analytical approach

Sustav za dinamičko pozicioniranje na bušačem brodu s dizalicom za teške terete

Zadatak ovog rada bio je odrediti granične radne uvjete za zadanu dizalicu na zadanom brodu, te prema dobivenom graničnom stanju mora, dimenzionirati snagu porivnog sustava dinamičkog pozicioniranja. Pri rješavanju zadatka korišteni su PREFEM, WADAM i POSTRESP moduli SESAM paketa, te diferencijalna jednadžba za devet stupnjeva slobode gibanja. Prema uputama programa [11] [12] [13] modelirao se model i opterećen je u stanju mirovanja jediničnim harmonijskim valom različitih frekvencija i izložen nailasku vala iz tri smjera. Dobiveni odzivi pomaka na svakoj frekvenciji prikazivali su prijenosne funkcije broda, dizalice i tereta koji se gibaju uslijed djelovanja nailaznog vala u krmu (0°), između krme i boka (45°) i u bok broda(90°). Za proračun prijenosnih funkcija tereta, u proširenu diferencijalnu jednadžbu koja je računala spregnute odzive tereta i broda unosili su se podaci dobiveni WADAM analizom. Korištenjem ERN "Envoirenmental Regularity Numbers (ern)" [8] brojeva, generirala su se stanja mora (ima ih ukupno 16), koja su prikazivana u postocima pojavljivanja. Množenjem kvadrata prijenosnih funkcija (RAO) sa svakim spektrom dobiveni su spektri odziva prema kojima su izračunati značajni odzivi pomaka, brzine i ubrzanja, broda, dizalice i tereta. Promatrane su tri točke vrha dizalice i tri točke tereta koji su definirane radnim položajem dizalice. Sve skupa generirano je 1152 spektra odziva, kako bi se mogli odrediti granični radni uvijeti za zadanu dizalicu na zadanom brodu, te snagu porivnog sustava dinamičkog pozicioniranja

Development of a simulation model to determine the key performance indicators of shipyard’s processing lines

Povijesni razvoj proizvodne industrije i njena uloga u suvremenom gospodarstvu prikazani su u uvodnom odlomku, a u nastavku se ističe važnost brodograđevne industrije u svijetu i u Hrvatskoj. Podpoglavlje Projektiranje i analiza proizvodnih sustava podcrtava smisao proizvodnje te načine na koje se ona može unaprijediti, odnosno kategorizirati. Pregled literature daje uvid u dosadašnje istraživanje proizvodne industrije uz istaknute nedostatke vezane uz brodograđevnu industriju. Cilj ovog istraživanja je razvoj simulacijskog modela kojim će se omogućiti evaluacija ključnih značajki serijskih Bernoullijevih proizvodnih linija. Drugo poglavlje opisuje osnovne teorije skupova i Markovljevih lanaca na kojima se temelji razvoj modela. Serijske proizvodne linije i linije s grananjem tokova materijala s nepouzdanim strojevima i konačnim kapacitetom međuskladišta pri konstantom, homogenom, vremenu izrade su opisane u trećem i četvrtom poglavlju. Pritom su detaljno objašnjeni prostor stanja, ključne značajke, analitičko rešenje i nova metoda konačnih stanja. Peto poglavlje definira uska grla za razne ključne značajke te opisuje projektiranje proizvodnih sustava pomoću metode diferencijalne evolucije. U kratkom šestom poglavlju opisuje se novonastali simulacijski model razvijen u programskom jeziku FORTRAN, a u sedmome je prikazana njegova primjena u slučaju brodograđevnom proizvodnom sustavu. Usporedba ključnih značajki dobivenih metodom konačnih stanja s analitičkim pristupom potvrdila je točnost metode, a primjena je potvrdila mogućnost upotrebe modela u stvarnom okruženju. Razvijena metoda konačnih stanja proširena s diferencijalnom evolucijom pokazala se kao dobar alat za projektiranje novih proizvodnih postrojenja.The manufacturing industry is part of the global economy, and its development is closely related to modern civilization's historical progress based on science and technology. The introduction part of chapter one is highlighting these achievements and shows the relationship between the manufacturing industry and the economic growth of a country. The first subheading of chapter one shortly describes the historical tradition of the global shipbuilding industry and shows which countries are the major players. The next subheading gives a short review of the Croatian shipbuilding industry followed by a summary on design and analysis of production systems. The main goal of this doctoral thesis as well as the hypothesis are outlined after the literature review. The main goal is the development of a new simulation model which will enable the evaluation of key performance indicators of serial Bernoulli lines. The hypotheses address the possibility that a new model for serial and splitting production lines can be established using a new method named the finite state method employed to calculate the key performance indicators. As compared to conventional methods, such a new approach will result in better design solutions of manufacturing systems, especially of the ship prefabrication and fabrication lines. The second chapter contains an overview the theory of sets and stochastic processes, namely the Markovian chains. Therefore, the basic terms on Ven diagrams, set operators, set algebra, probability theory and stochastic processes are outlined. The discrete time Markovian chains are elaborated and explained more deeply, the Chapman-Kolmogorov equation is shown and the eigenvalue problem is briefly presented. Chapter three deals with the definition of serials lines and the necessary assumptions needed to describe a Bernoulli distribution. In the first subheading the system state space is presented and explained. The next subheading briefly presents the recently developed general analytical solution to formulate the transition matrix. However, this approach is quite challenging and time consuming due to the exceptional complexity of the system state space. Therefore, the finite state method was developed based on the proportionality of the system state space to reduce the evaluation time for lager system states. The aggregation method and a simulation approach are briefly presented for the purpose of comparison with the finite state method and the analytical approach. Such a comparison was done for the first time. The results are highlighted in a short discussion with the conclusion that the new finite state method is worth to be further developed for the case of splitting lines. The chapter four presents the definition of splitting lines and defines the analytical approach. The finite state method for splitting lines was elaborated in the next subheading. The finite state method for splitting lines was validated against the analytical approach and via application case using various expressions for the key performance indicators. At the end, the results prove that the finite state method is capable to model a splitting line and to calculate the required key performance indicators. The finite state method is employed to calculate the eigenvector for the entire system state. This feature enables evaluation of bottlenecks for all key performance indicators. The expressions for such operations are listen in the chapter five. At the end of this chapter the differential evolution theory, is combined with the finite state method and a new design methodology is presented. The chapter six contains the scheme of the new simulation tool ShipProLab developed in FORTRAN using the analytical approach and the finite state method. In chapter seven an illustrative example of a prefabrication and fabrication production line is presented. In this example, the developed theory is employed to determine the key performance indicators and to calculate the time required to compete production of two typical ship sections. Therefore, a brief description of the facility is given including the substitute models. A new facility is designed using the differential evolution theory. The last chapter summarizes the main conclusions of the research. The newly developed finite state method is highlighted as a powerful tool to calculate the key performance indicators for serial and splitting lines that, in combination with the differential evolution theory, enables a sophisticated approach to design issues related to production system engineering

Dynamic positioning system on the drill-ship with a crane for heavy lifting operations

Zadatak ovog rada bio je odrediti granične radne uvjete za zadanu dizalicu na zadanom brodu, te prema dobivenom graničnom stanju mora, dimenzionirati snagu porivnog sustava dinamičkog pozicioniranja. Pri rješavanju zadatka korišteni su PREFEM, WADAM i POSTRESP moduli SESAM paketa, te diferencijalna jednadžba za devet stupnjeva slobode gibanja. Prema uputama programa [11] [12] [13] modelirao se model i opterećen je u stanju mirovanja jediničnim harmonijskim valom različitih frekvencija i izložen nailasku vala iz tri smjera. Dobiveni odzivi pomaka na svakoj frekvenciji prikazivali su prijenosne funkcije broda, dizalice i tereta koji se gibaju uslijed djelovanja nailaznog vala u krmu (0°), između krme i boka (45°) i u bok broda(90°). Za proračun prijenosnih funkcija tereta, u proširenu diferencijalnu jednadžbu koja je računala spregnute odzive tereta i broda unosili su se podaci dobiveni WADAM analizom. Korištenjem ERN "Envoirenmental Regularity Numbers (ern)" [8] brojeva, generirala su se stanja mora (ima ih ukupno 16), koja su prikazivana u postocima pojavljivanja. Množenjem kvadrata prijenosnih funkcija (RAO) sa svakim spektrom dobiveni su spektri odziva prema kojima su izračunati značajni odzivi pomaka, brzine i ubrzanja, broda, dizalice i tereta. Promatrane su tri točke vrha dizalice i tri točke tereta koji su definirane radnim položajem dizalice. Sve skupa generirano je 1152 spektra odziva, kako bi se mogli odrediti granični radni uvijeti za zadanu dizalicu na zadanom brodu, te snagu porivnog sustava dinamičkog pozicioniranja

Development of a simulation model to determine the key performance indicators of shipyard’s processing lines

Povijesni razvoj proizvodne industrije i njena uloga u suvremenom gospodarstvu prikazani su u uvodnom odlomku, a u nastavku se ističe važnost brodograđevne industrije u svijetu i u Hrvatskoj. Podpoglavlje Projektiranje i analiza proizvodnih sustava podcrtava smisao proizvodnje te načine na koje se ona može unaprijediti, odnosno kategorizirati. Pregled literature daje uvid u dosadašnje istraživanje proizvodne industrije uz istaknute nedostatke vezane uz brodograđevnu industriju. Cilj ovog istraživanja je razvoj simulacijskog modela kojim će se omogućiti evaluacija ključnih značajki serijskih Bernoullijevih proizvodnih linija. Drugo poglavlje opisuje osnovne teorije skupova i Markovljevih lanaca na kojima se temelji razvoj modela. Serijske proizvodne linije i linije s grananjem tokova materijala s nepouzdanim strojevima i konačnim kapacitetom međuskladišta pri konstantom, homogenom, vremenu izrade su opisane u trećem i četvrtom poglavlju. Pritom su detaljno objašnjeni prostor stanja, ključne značajke, analitičko rešenje i nova metoda konačnih stanja. Peto poglavlje definira uska grla za razne ključne značajke te opisuje projektiranje proizvodnih sustava pomoću metode diferencijalne evolucije. U kratkom šestom poglavlju opisuje se novonastali simulacijski model razvijen u programskom jeziku FORTRAN, a u sedmome je prikazana njegova primjena u slučaju brodograđevnom proizvodnom sustavu. Usporedba ključnih značajki dobivenih metodom konačnih stanja s analitičkim pristupom potvrdila je točnost metode, a primjena je potvrdila mogućnost upotrebe modela u stvarnom okruženju. Razvijena metoda konačnih stanja proširena s diferencijalnom evolucijom pokazala se kao dobar alat za projektiranje novih proizvodnih postrojenja.The manufacturing industry is part of the global economy, and its development is closely related to modern civilization's historical progress based on science and technology. The introduction part of chapter one is highlighting these achievements and shows the relationship between the manufacturing industry and the economic growth of a country. The first subheading of chapter one shortly describes the historical tradition of the global shipbuilding industry and shows which countries are the major players. The next subheading gives a short review of the Croatian shipbuilding industry followed by a summary on design and analysis of production systems. The main goal of this doctoral thesis as well as the hypothesis are outlined after the literature review. The main goal is the development of a new simulation model which will enable the evaluation of key performance indicators of serial Bernoulli lines. The hypotheses address the possibility that a new model for serial and splitting production lines can be established using a new method named the finite state method employed to calculate the key performance indicators. As compared to conventional methods, such a new approach will result in better design solutions of manufacturing systems, especially of the ship prefabrication and fabrication lines. The second chapter contains an overview the theory of sets and stochastic processes, namely the Markovian chains. Therefore, the basic terms on Ven diagrams, set operators, set algebra, probability theory and stochastic processes are outlined. The discrete time Markovian chains are elaborated and explained more deeply, the Chapman-Kolmogorov equation is shown and the eigenvalue problem is briefly presented. Chapter three deals with the definition of serials lines and the necessary assumptions needed to describe a Bernoulli distribution. In the first subheading the system state space is presented and explained. The next subheading briefly presents the recently developed general analytical solution to formulate the transition matrix. However, this approach is quite challenging and time consuming due to the exceptional complexity of the system state space. Therefore, the finite state method was developed based on the proportionality of the system state space to reduce the evaluation time for lager system states. The aggregation method and a simulation approach are briefly presented for the purpose of comparison with the finite state method and the analytical approach. Such a comparison was done for the first time. The results are highlighted in a short discussion with the conclusion that the new finite state method is worth to be further developed for the case of splitting lines. The chapter four presents the definition of splitting lines and defines the analytical approach. The finite state method for splitting lines was elaborated in the next subheading. The finite state method for splitting lines was validated against the analytical approach and via application case using various expressions for the key performance indicators. At the end, the results prove that the finite state method is capable to model a splitting line and to calculate the required key performance indicators. The finite state method is employed to calculate the eigenvector for the entire system state. This feature enables evaluation of bottlenecks for all key performance indicators. The expressions for such operations are listen in the chapter five. At the end of this chapter the differential evolution theory, is combined with the finite state method and a new design methodology is presented. The chapter six contains the scheme of the new simulation tool ShipProLab developed in FORTRAN using the analytical approach and the finite state method. In chapter seven an illustrative example of a prefabrication and fabrication production line is presented. In this example, the developed theory is employed to determine the key performance indicators and to calculate the time required to compete production of two typical ship sections. Therefore, a brief description of the facility is given including the substitute models. A new facility is designed using the differential evolution theory. The last chapter summarizes the main conclusions of the research. The newly developed finite state method is highlighted as a powerful tool to calculate the key performance indicators for serial and splitting lines that, in combination with the differential evolution theory, enables a sophisticated approach to design issues related to production system engineering

Dynamic positioning system on the drill-ship with a crane for heavy lifting operations

Zadatak ovog rada bio je odrediti granične radne uvjete za zadanu dizalicu na zadanom brodu, te prema dobivenom graničnom stanju mora, dimenzionirati snagu porivnog sustava dinamičkog pozicioniranja. Pri rješavanju zadatka korišteni su PREFEM, WADAM i POSTRESP moduli SESAM paketa, te diferencijalna jednadžba za devet stupnjeva slobode gibanja. Prema uputama programa [11] [12] [13] modelirao se model i opterećen je u stanju mirovanja jediničnim harmonijskim valom različitih frekvencija i izložen nailasku vala iz tri smjera. Dobiveni odzivi pomaka na svakoj frekvenciji prikazivali su prijenosne funkcije broda, dizalice i tereta koji se gibaju uslijed djelovanja nailaznog vala u krmu (0°), između krme i boka (45°) i u bok broda(90°). Za proračun prijenosnih funkcija tereta, u proširenu diferencijalnu jednadžbu koja je računala spregnute odzive tereta i broda unosili su se podaci dobiveni WADAM analizom. Korištenjem ERN "Envoirenmental Regularity Numbers (ern)" [8] brojeva, generirala su se stanja mora (ima ih ukupno 16), koja su prikazivana u postocima pojavljivanja. Množenjem kvadrata prijenosnih funkcija (RAO) sa svakim spektrom dobiveni su spektri odziva prema kojima su izračunati značajni odzivi pomaka, brzine i ubrzanja, broda, dizalice i tereta. Promatrane su tri točke vrha dizalice i tri točke tereta koji su definirane radnim položajem dizalice. Sve skupa generirano je 1152 spektra odziva, kako bi se mogli odrediti granični radni uvijeti za zadanu dizalicu na zadanom brodu, te snagu porivnog sustava dinamičkog pozicioniranja