Integrated ship design: Automated Generation of Production Deliverables with New Generation Shipbuilding CAD Systems

Vittorio Bucci, University of Trieste, Trieste/Italy, vbucci@units.it

Alberto Marinò, University of Trieste, Trieste/Italy, marino@units.it Igor Juricic, Intergraph, Milano/Italy, igor.juricic@intergraph.com

Abstract It is considered the possible level of automation for the outputs of production deliverables obtainable

with the latest generation of computer-aided design systems dedicated to ship and offshore design and

construction. The paper points out the possibility of ensuring fast and accurate updates of the

production deliverables when changes during the design process occur. With reference to stiffened

plate structures of a typical hull appendage, a series of tests has been carried out, considering both a

homogenous CAD environment and different CAD systems that externalize their data via XML for

interface reasons.

1. Introduction In the ship acquisition process the design phase immediately follows the planning phase. The planning involves different activities, mainly concerning with the strategy of a certain business. Different strategic objectives shall be analyzed in order to define which vessel will be able to maximize the profitability of the investment. Here is taken the decision whether the ship to be purchased will be a new ship or a second-hand/converted/modified existing ship. In the design phase all the requirements and needs stressed in previous planning phase are collected, and proper solutions are proposed in order to establish efficient configuration, shape, dimensions and other characteristics of the ship to be acquired. Design process involves also engineering activities where structures are defined and the components of the various systems to be fitted are selected. It shall be considered that different conflicting aspects of the design theme shall be faced, and, in general by an iterative and repetitive stepwise method, proper solutions will be found. In this manner the convergence towards final review of the project is assured in order to realize the definitive product. Nowadays, the different design steps can be sped up through the use of computer-based tools more and more linked and integrated. The opportunities offered by the current advance of the computer technology allow multiple and deeper investigations in a shorter time, and so improving significantly the efficiency of the entire process, to be more competitive in the global marketplace. The efforts of the designers are to be addressed to obtain a product satisfying the ship owner's requirements at minimum costs. Obviously, all the costs involved in the ship's life cycle (design, construction, operating and support costs) are to be considered. 2. The ship design process Ship design process is a quite long and articulated path beginning with the results obtained from the planning analysis and that finishes when the new product is delivered. Drawings and/or 3D computer models, specifications and all the information needed for the production are to be elaborated. The entire design process is subdivided into different stages separated by intervals in which reviews are issued and deliverables are developed as references for the next stage. A manner to collect the various stages of the ship design process is that to distinguish between Basic Design and Product Engineering. In the basic design the ship is treated in its entirety and designed on

a system-by-system basis, while in the product engineering the deliverables developed in the previous phase are detailed into a form suitable for the production techniques to be adopted by the shipbuilder. In the ship design process a stage particularly demanding is the one named Functional Design, where each system of the ship is fully defined and all its components are selected and sized, also complying with the requirements imposed by the ship owner and the regulatory bodies. The functional design stage, being system oriented, can be seen as the final stage of the basic design phase. Alternatively, it can be seen also as the first stage of the production engineering phase, because it concerns with activities that are preparatory for the detailing of the systems onboard. In Fig.1 this option for the functional design stage is depicted, along with the other stages of the ship design process.

Fig.1: Ship design process In the basic design phase the following stages can be distinguished:

• Concept Design, where the ship owner's requirements in terms of mission and main performances of the ship are refined in strict collaboration with designers. The latter have here the task to perform a technical feasibility analysis along with an economic analysis in order to elaborate various syntheses from which draw a practical ship design solution within the ship owner's budget.

• Preliminary Design, where the vessel conceived with a few broad lines in the previous stage begins to assume specific features. Ship size and overall configuration are established, major components of the ship are selected and simple single-line diagrams for each system are traced. Thus a refined technical feasibility analysis can be carried out and assessed. The top-level ship performances are quantified, while the secondary ones are just outlined to be later on investigated. The level of detail reached in this stage shall be sufficient to estimate construction, operating and support costs in order to finalize the economic feasibility of the investment. Moreover, a generic build strategy (reflecting only block and zone definitions to be employed during ship construction, while the sequence of assembling will be later defined) is drafted. At the end of the preliminary design, analyses aimed to reduce or eliminate major technical, cost and schedule risks are carried out.

• Contract Design, which concerns with the development of a set of documents useful to accurately describe the ship to be built and to avoid misunderstanding between the parties (ship owner and shipbuilder) involved. Specifically, it will be issued a contract and a technical specification along with explanatory drawings. Usually, there is an accepted hierarchy among

these documents: the contract prevails on the specification, which in turns prevails on drawings. In the specification, taking also into account the preferences of both the ship owner and the shipbuilder, the main characteristics of the ship are listed and all the systems onboard are described and defined in their size and performances. Particular attention will be paid to ensure that there are no conflicting requirements between the various sections of the specification and the related drawings. General arrangement can be considered the most important drawing developed in this stage because it is the point of reference for the different systems fitted on shipboard. Purchase technical specifications of the main machinery are in general early issued, in consideration of their long lead time. The build strategy sketched in the preliminary design is now reviewed and definitely established (block, zone and assembly sequence). Moreover, the ship production plan, reporting the ship assembly schedule, is set.

• Functional Design, where design calculations and configuration of the various systems are completed. In particular, detailed naval architectural calculations are performed, the hull scantlings are developed and piping, electrical wiring, vent ducting are sized and the system routings are traced in a preliminary way. Material quantities and weights are tabulated system by system, and the first revision of the budget control list is issued. Purchase technical specifications not drawn up in the previous contract design stage are now issued, while purchase order specifications for the main machinery already considered (during the contract design stage) are addressed to vendors. Finally, this stage is concluded when ship owner and regulatory bodies’ approvals are achieved.

The Product Engineering phase, being mainly a detail design phase oriented to production, can be divided into the following stages:

• Transition Design, where the system-oriented information collected in the previous stages is arranged into zone-oriented information. The ship is divided into a certain number of zones in accordance with the build strategy already established, and yard plans are generated in order to efficiently organize the production work. For each zone two sets of yard plans are elaborated: one concerning the detailing of the structures and another one concerning the positioning of all systems' components (no matter how small) to be fitted in the zone considered. The merging of the hull's yard plans with the systems' yard plans makes the zone composite arrangement up. Through the yard plans it is possible to elaborate a list of materials to be used in the zone as well as evaluate weight and centre of gravity of the zone. The main objective of the zone composite arrangement drawings is that to detect if any interference (between either the various systems or systems and structures) occurs.

• Work Instruction Design, which is the most pertinent stage addressed to production. In fact, instructions to manufacture the various parts of the ship (systems and structures) and how to fit them together are given, also in accordance both with the established build strategy and with the technologies adopted by the shipbuilder. Therefore, manufacturing work instruction drawings and fitting work instruction drawings shall be prepared. The components of the various systems in a certain zone are now grouped on a kind basis (for example, pipe pieces, ventilation duct pieces, supports, etc.), and manufacturing work instructions sufficiently detailed are given piece by piece (regardless of where they are to be manufactured). The next step involves the preparation of fitting work instructions that permit to assembly the blocks with the different items previously manufactured. In order to facilitate either the manufacturing or the fitting work, consistent material lists are prepared (i.e., material lists for manufacturing and material lists for fitting).

3. The role of the computer software in the integrated design process Nowadays the usage of efficient and coordinated computer-based tools in the ship design and construction process represents an important aspect to evaluate the commercial competitiveness of a shipbuilder. In fact, by means of such tools quicker responses to ship-owner’s requests for quotations can be given. Moreover, the accuracy of the deliverables shall be increased.

Design modifications can be performed in a more flexible way, ensuring also high level of consistency. The possibility to create computer simulations with a 3D product model allows the enhancement of the activities related to both concurrent engineering and production planning. Cost control analyses are improved, and rational and timely materials and outfit acquisitions are permitted. Obviously, all these computer-based activities need a common database that should be continuously updated in order to always get reliable information. Computer-aided functions involved in the ship design and production process deal with synthesis modelling, design (CAD), engineering (CAE), manufacturing (CAM), product model, computer integrated manufacturing (CIM) and computer systems integration. The traditional way to perform the ship design and construction process is essentially based on the following classes of programs:

• Computer-Aided Synthesis Modelling can be considered the starting point to define a baseline on which successively the preliminary design of the vessel is developed. Specifically, the design data are elaborated taking into consideration either a parent ship or a number of similar ships. The outputs obtained may concern design, operation or cost issues.

• Computer-Aided Design (CAD) represents the natural evolution consequent to the introduction of the computer in the elaboration of drawings. Although the most of drawings are traced on a computer monitor, the final outputs are still printed on paper. The trend of the modern CAD systems is oriented towards 3D models, so that operators can have a more direct perception of what they are creating.

• Computer-Aided Engineering (CAE) programs enable the various calculations inherent in the design process. There are CAE programs dedicated to specific tasks (for instance, hydrostatics and stability, weight and centres, speed/power, structure, pipe sizing, electric loading, seakeeping, noise, etc.), but modern CAE programs are often made-up of different modules (each for a specific task) linked to each other. Some CAE programs are specifically dedicated to give quick responses to ship owner's inquires. They draw a proper database from which parametric relationships can be derived in order to set up an initial design and then perform preliminary cost estimation, useful to carry out the subsequent trade-off analyses.

• Computer-Aided Manufacturing (CAM) programs represent the tools that allow the transition from the design towards the construction of the ship. In other terms, all the outcomes obtained in the stages regarding the functional design are now developed and converted pro the construction activities (e.g. welding, cutting, painting, lifting, bending, forming, planning and monitoring). An important aspect that a CAM system should have is the ability to elaborate the necessary digital data in a consistent manner with the shipyard facilities and standards.

Fig.2: Ship design and construction process according to the traditional way

An alternative approach to the traditional computer-based tools is given by the Product Model Programs, which include both CAD, CAE and (in some extent) CAM capabilities. The great merit of such programs lies in their 3-dimensionality. In fact, users work with a 3D model since the earliest stages of the design, against the traditional approach where the work is performed in 2D in the

preliminary stages and then is extended to 3D in the detailing stages. The Product Model Programs permit also to simultaneously carry out different tasks within a multi-user environment. In such a way it is quite easy to check interior spaces (with particular attention to maintenance clearance) or interference existing between structures and outfitting. Moreover, an important aspect to be considered is that the different tasks can be performed only with the dedicated modules belonging to the same Product Model Program. In other words, there is no integration with the modules of different Product Model Programs (such a capability, instead, is obtained by the Computer Systems Integration, hereunder treated).

Fig.3: Ship design and construction process based on Product Model Program

A still more advanced approach than Product Model Programs is that provided by Computer-Integrated Manufacturing (CIM) programs. The latter could be seen as enhanced Product Model Programs, especially for the manufacturing activities, and with the considerable capability of coordinating stand-alone programs that are interfaced with a common database. However, the stand-alone programs need to be tailored to comply with the individual shipyard's facilities, technologies and standards. Within a CIM environment, owing to the common database, the management of information between technical and administrative divisions is thoroughly consistent. Further important feature is represented by the possibility to manage the data states in accordance with the different decision-making levels existing in the hierarchical organization of the shipyard.

Fig.4: Ship design and construction process based on Computer-Integrated Manufacturing A challenge for the shipbuilding industry is represented by Computer Systems Integration. The achievement of the fully integration among different computer systems allows the link of different organizations, all aimed to the same project. While a CIM program is calibrated only in accordance with the capability of a specific shipyard, the Computer System Integration involves many figures (i.e., shipyards, ship-owners, suppliers, classification societies, regulatory bodies and so on). Obviously, a common database should be shared among the various figures, in order to allow them to always work with reliable and consistent information.

Fig.5: Ship design and construction process based on Computer Systems Integration

4. The infrastructure to support the Integrated Design To achieve major productivity and cost efficiency, improvements in the segments of the vertical process are beneficial, but are not sufficient: a solution that can manage the rate of speed of changes is required. Intergraph’s information management solution provides a collaborative tool able to ensure that valid, consistent, and high-quality engineering data is shared between applications and users when and where it is needed.

Fig.6: Suite of data-centric design, engineering and information management applications

A broader horizontal strategy is needed that extends through the engineering, business, material management, production, and lifecycle management domains. Considering the complexity of the process, and the fact that there is no single tool able to cover all of its facets, an open solution should be found. Such a solution should be able to both manage the communication among the various authoring tools and follow the evolution of the design and the engineering due to the change requests coming from each participant (designers, owners, builders, regulatory and classification bodies). The capital Product Lifecycle Management (cPLM) is an open, scalable solution that can serve as a platform for the integration and data repository functions, where global project information can be created, managed, reused and controlled throughout the product lifecycle. It provides a mechanism for marine industries to use one or more products from own suite in conjunction with a number and variety of third party tools that can be integrated through the platform. The solution supports global collaboration between clients, contractors and suppliers, and helps business processes that share common information. These overarching and collaborative workflows through internal and external value chains deliver quality information to the desktop, regardless of the source application, forming a single source of access to the engineering data of the ship or the marine asset. In such a way it is ensured a reliable support to regulatory reviews, as well as to enhanced decisions by means of cross-discipline, cross-referenced data and indices.

Fig.7: Role of the specific application portal to utilize consolidated data at enterprise level

The total integration of the engineering data in a single-source data entry enables quick identification and resolution of potential problems; timely information and project reporting with seamless inter-faces for corporate financial, accounting and planning applications are so guaranteed. 5. Smooth and flexible transition through design phases

Intergraph has partnered with world-leading and innovative best-practice shipbuilders to provide a next-generation fully integrated 3D modeller, in which structural and outfitting tasks are carried out by a “seamless” process through basic design, detailed design, and construction phases without the need of any re-modelling. Changes of the hull form or other plate systems trigger the automatic update of the involved hull structures and (after a specific permission) of the outfitting components related to the modified structures. Structural openings for pipe/duct/cableway penetrations are all generated automatically in accordance with rules concerning the tightness of the plate system and the compartment/zone type. The above mentioned automatic update, in addition to save time, provides consistent accuracy and improves design quality, and has a beneficial influence both on production processes and on schedules. Moreover, a more comprehensive basic design can be performed with shorter overall delivery times. 5.1 Basic Design SmartMarine 3D represents an advanced marine asset and ship design software offered by Intergraph. Various SmartMarine tasks are activated to generate the functional/system view of the design. The common objective is to use a unique product model of the ship/floater for all early design tasks in order to perform strength assessment, hydrostatics, stability analyses and other naval architectural calculations, as well as specific engineering analyses for piping, HVAC and electrical systems. Tools and features for preliminary ship/marine design include:

• A complete 3D digital product model that should be considered as the "master" and the unique valid source of information for all the life-cycle applications.

• A rule-driven structural design in order to support all arrangements, connections and block divisions.

• Flexibility to select the hull and surfacing design tools, as well as the ability to exchange compartment data received from other well-known initial design packages, such as NAPA.

• The idealisation of the model that, in addition to the hydrostatic and hydrodynamic calculations, can be used for the finite-element analyses (FEA) by solvers as ANSYS, Nastran

(MSC) or Sestre (DNV). So that a fast assessment of the vessel structure is allowed, and the optimization of the solution (with respect to any design objective) adopted is facilitated.

• Comprehensive equipment, piping, structure and space management functions. Different pipe-run interfaces are available as direct user input, import from spreadsheets or Piping and In-strumentation Diagram (P&ID). User-defined layout design rules can be used to monitor and, where necessary, to enforce industry or design standards for the equipment placement, piping configuration and spacing. In addition, for a given layout, an integrated pipe AutoRouter cal-culates and displays the pipe routes with the lowest possible cost complying with the applied design standards.

• Automated definition of drawings and reports, including bulk materials quantities reports for cost estimation purposes.

•

Fig.8: Aft part of a ship emphasizing structural vs outfitting content

To perform strength assessment based on classification rules or other structural analyses it is assumed that the solution will make available the model and the associated properties to the CAE system with-out having to add design efforts or to re-model. A robust and efficient interface is needed to manage exceptions and to overcome to possible data inconsistency issues, since the CAD model have to be simplified without losing correctness from the perspective of the analysis tool. An Application Programming Interface (API) approach combined with XML has been used to inter-face the SmartMarine 3D structures with a section scantlings software (Nauticus by DNV). There is also an interface with Sesam GeniE (by DNV).

Fig.9: The interface allowing CAD model to be used by analysis tools

In the development of the interface an important step is the transformation from the internal object model to a suitable model for exchange of data between different applications (i.e., create the "ex-change model" to be used by the solution integrator). The exchange model does not contain the com-plete internal object model, but only data of interest for the integration, in particular it describes the structure and the format of the data to be exchanged. In parallel, the interface needs another model where to describe how to interpret the treated data. This is the "reference model" that inherits the ex-change model and adds semantics to enable interpretation of the data, so allowing an effective ex-change of "models" between collaborating applications. Clearly, in this manner redundant modelling are eliminated and possible errors are reduced, moreover the classification and the whole approval process is sped up. 5.2 Product Engineering and Planning The ability of SmartMarine 3D of treating the vessel model as a whole in all the phases of the design along with the integration with planning tasks gives the design-to-production approach a considerable competitive advantage. As a matter of fact, it is able to automatically generate up to 90% of the structural details starting from the functional model and more than 95% of manufactured parts from the detailed model. The design intent is attained via design rules and relationships between structural and outfitting items. The increased overall data quality and integrity helps to retain engineering and corporate knowledge for future applications. Building blocks are defined in the earliest stages of the design. The assembly planning task, besides weights and centres of gravity, enables to define the assembly orientation, foot-print and mounting sequence, which are pre-requisites for the automatic generation of the building instructions for the workshop, as well as for plotting dedicated assembly drawings. In particular, the task enables the definition of assembly and sub-assembly structures, specifies the work-centre assignments and determines the assembly sequencing. Without rework, all this information will be refined up to the lowest level during the progress of the project. A building simulation can be performed at any stage of the project with planning data linked to schedule information (master and procurement) in order to check the alignment with the building strategy. The links with external/third party planning and scheduling systems are easily made, especially with MS OLE-enabled applications. Such a tight integration makes changes and updates to schedules extremely simple. Furthermore, logistics for materials distribution is greatly improved. 6. Automation in the generation of deliverables at any design stage Proper filters allow the retrieving of specific data from the relational database and their visualization in a user-friendly manner during the design-to-production process, without writing complex queries. All the deliverables, as drawings and reports, are generated by a similar procedure: i.e., extracted via implicit queries and then re-symbolized to fit industry standards or requirements of customized representations, at any time. Typical piping isometric sketches or pipe-support manufacturing drawings or profile sketches are generated out-of-the-box and no end-user touch-up is expected. Scantling drawings of blocks and their plate systems are also automatically generated, usually following the ISO128-25 standard. General Arrangement drawings, as the Plot Plan shown below, have to consider the addition of limited touch-up (additional labels or dimensions) by the end-user, touch-up that will be anyhow noted in case of changes to the model, as if they were automatically generated by the system.

Fig.10: Flow-diagrams showing object re-symbolization in drawing generation process

Fig.11: Plot Plan of a platform and scantling drawing of a deck

7. Test case During Spring 2012 at the Department of Engineering and Architecture, Division of Naval Architecture, of the University of Trieste started an education program on ship integrated design using SmartMarine 3D and a number of third-party applications to simulate a design-to-production process. The main target of such an education program was that to apply commercial tools both in the design and in the generation of deliverables during the complete design process of a typical hull appendage. The design of a semi-spade rudder has been carried out, and the management of a major change in dimensions has been also checked. 7.1 The transfer of the model towards programs for specific analyses The question of linking between systems (in practice the exchanging data) implies the identification of comprehensive information to be given in a proper format and content. Although there is a series of standards for data exchange, their applicability is limited, because the more functional the standard is, the more complex its use is and the more expensive it becomes. The universality required from the standard for data exchange represents an additional difficulty for an efficient data transfer. For the reasons specified, the so-called “point-to-point” solutions are the optimum for the linkage when the two systems to be connected are known. A detailed data description from a particular system is an essential prerequisite for the achievement of such an interface, and the presentation of the data using

the XML facilitates the understanding by the receiving system. TRIDENT (by USCS, Uljanik Shipbuilding Computer System) is a system whose basic task is to complement the CAD/CAE systems in specific areas where, by means of its specialised internal modules, makes it possible to increase the completeness or the efficiency of the overall design-to-production work. The TRIDENT system is already an integrated solution with individual modules (for instance Painting and Nesting) having a great functionality, which makes attractive the interfacing with other CAD systems as well. By the test case performed the development of the programming interface (API) for data exchange between Intergraph SmartMarine 3D structural elements and the TRIDENT modules has been checked and refined. Prerequisite for such a development was that both systems had well established mechanisms for data exchange based on XML. The technology uses XSD data schema and allows a fast and simple definition of the connections between systems, together with adapting capabilities in the case of new requirements or changes.

Fig.12: Flow diagram of the SmartMarine 3D → TRIDENT Nesting interface

The method applied to build the API facilitates the independent updates of the software on both platforms, as the uneven publishing of new revisions of software represents one of the known problems in the “point-to-point” interfaces between applications. 7.2 The connection between SmartMarine 3D and third-party tools in different design phases The structural modelling within SmartMarine 3D supports three different levels of element definition, depending of the phase of the project. The data in each phase are characterized by a different complexity due to the degree of details displayed. In each phase, it is possible to obtain a record of the structure data in the form of XML files. The TRIDENT modules accept and return data by means of a dedicated import/export mechanism specially developed. During the import session, each importer can generate data containing information on how transform the imported data into another format. This approach enables to combine the functionalities of SmartMarine 3D with those of a particular TRIDENT module (apart the complexity or the level of definition considered).

Fig.13: SmartMarine 3D Molded Forms modelling task and TRIDENT application GUI

7.3 The interface towards generic analysis and production modules The data transfer between SmartMarine 3D (SM3D) and the TRIDENT modules has been validated using the data drawn from a rudder modelled in SmartMarine environment. Interface is made through the following phases: • During the first phase (Basic Design) the data is transferred from SM3D to TRIDENT Ship Ex-

plorer. This phase is characterized by poorly detailed elements, but good enough to carry out various analyses based on the transformation of the structural elements in finite elements. For the test case, the validation of the interface was based on a visual exam.

• The second phase (Detailed Design) is the data transfer from SM3D to the module TRIDENT Painting. The elements are completely defined from the point of view of a 3D model. Because of the data organization in TRIDENT Painting, the SM3D data has to be loaded in the hierarchy structure of the project/yard. The results obtained with the TRIDENT Painting module showed that the quality of the transferred SM3D elements did not differ from the ones natively obtained by the TRIDENT system.

• During the third phase (Structural Manufacturing) the SM3D elements data is simplified in terms of geometry, but provided with additional attributes necessary for the production (i.e., marking, bevelling, welding, margins and dimensions inclusive of shrinkage factor). All this data is used in TRIDENT Nesting. The test case showed that the transferred elements, with some known excep-tions (the bevelling data was connected with weld data, while grinding data was ignored), could be successfully nested, and the corresponding NC programs for cutting machines generated.

7.4 The Finite-Element Analysis and the role of the intermediate mesh generator Another ambit of the test case has also included the transfer of the SmartMarrine 3D model towards Finite-Element Analysis (FEA) modules via a generic mesh generator named CAFE (by BVB). One of the main benefits of the integration between SmartMarine 3D and CAFE is the possibility to avoid redundant tasks and unnecessary loss of time on remodelling in FEA environment structures already defined in a CAD environment. The process is iterative and the workflow is not uniquely identified, since marine structures may require different objectives of analysis, depending on design phase. Initially, at the Basic Design phase it is necessary to validate the structural dimensioning and the relationships among the various members. In a subsequent phase, the interface to transfer the structural model to a FEA environment has to be activated. In such a workflow the CAFE module plays the role of intelligent mesh generator able to prepare the model for the FEA solver (ANSYS for the test performed).

Fig.14: The role of CAFE mesh generator and the rudder model in ANSYS

In the test case the plate members have been successfully transferred, but due to CAFE limitations in treating solids (e.g. casted and forged elements) considerable touch-ups needed to get a suitable model for the FEA environment.

7.5 The interface with the production systems It has been tested the module of TRIDENT for nesting (TRIDENT Nesting). Different element types are used to define the geometry of plates in SmartMarine 3D and in TRIDENT Nesting (i.e., SMS_PLATE_TYPE in SmartMarine 3D and Nesting element in TRIDENT, respectively). It is worth noting that the SMS_PLATE_TYPE element is more complex than the TRIDENT Nesting element. The contour of the SMS_PLATE_TYPE element is divided into several edges which in turn are defined by the CVG_CURVE through a series of vertices representing the ends of linked straight-lines and arcs; moreover for each edge are also defined further properties like surface treatment (grinding) and bevelling. The TRIDENT Nesting element instead has a contour simply defined by a series of 3D points.

Fig.15: Definition of the plate contour in SmartMarine 3D and in TRIDENT Nesting

Therefore, the conversion of the plate contour from SmartMarine 3D to TRIDENT Nesting, involves a loss of information about the geometry of edges and their properties (grinding, bevelling). Such a deficiency is partially resolved by writing the information about the bevel of the edge to be welded next to the marking of the piece, but in this manner the grinding information is definitely lost.

Fig.16: A nested raw plate in TRIDENT Nesting after import from SmartMarine 3D

The test case has confirmed that plates can be transferred from SmartMarine 3D to TRIDENT Nesting without need of touch-ups, allowing also the generation of information for the NC cutting machines. All the information about the nested raw plate is returned to the engineering database via XML and/or a dedicated API routine. 8. Conclusions The different phases of the ship design process have been thoroughly examined in accordance with the traditional approach, and the different categories of programs that are commonly used in each phase have been described. In order to improve significantly the efficiency of the entire process nowadays the research is addressed to an intelligent integration of the different design environments. The basic concept concerns the creation of a unique 3D model of a vessel or a platform from which attain any information to be used both in the basic design and in product engineering stage. To this end a central database is an essential pre-requisite of the system. Of course, the stored data must have a format to be intelligible by any program used in the design-to-production process (planning, scheduling and purchasing included). Moreover, such a database must be able to receive all the data changes that occur during the workflow, updating automatically the master model. The management

of the data flows should be entrusted to a program ensuring a reliable link with specialized third-party tools. An important aspect during the design process concerns the issuing of updated and consistent deliverables (drawings and reports). Moreover, an integrated environment opens the possibility for a productive cooperation in various projects between companies that work with different systems. As a matter of fact the most complex, capital projects are seldom carried out within a single company because the demanding and specialized tasks and the tight deadlines make it necessary to divide the activities among cooperative partners. Of course, the strategy based on the integration of different disciplines requires significant investments in software, research and training of end-users, but it represents, own to the current state of the art, the only way to improve and shorten the overall design-to-production process. References LAMB, T. (Ed.) (2003), Ship Design and Construction, SNAME STORCH, R.L.; HAMMON, C.P.; BUNCH, H.M.; MOORE, R.C. (1995), Ship Production, Cornell Maritime Press MILANOVIĆ, M., BISTRIČIĆ, M., ŠIKIĆ, G., JURIČIĆ, I. (2012), Data exchange between CAD

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