rules-based and geometric construction connections - intergraph

T he offshore industry is changing target:the oil and gas and energy seekers aremoving deeper into the sea while the

offshore plant manufacturers are expanding thevariety of floating objects, with the purpose ofdrilling, processing, storing but also hosting eolicand other generators.The floating denominatoris pushing the offshore industry deep in thedomain of the traditional shipbuilding industry.The major shipbuilders have reached the top interms of produced ships (by number and DWT);they are merging the best practices of the ship-building mass-production with high value-added,one-of-a-kind, offshore floating plants.The article is considering some aspects of thementioned merger from the perspective ofdedicated structural CAD applications. Thereare constructions like jackets and topsides thatare commonly recognized as offshore specific;there are other constructions like double hullsand cambered decks that are commonly reco-gnized as ship specific.There have been alwaystransition areas, but today the need to mix“beams-plates” with “stiffened-plates” it is gro-wing for two different reasons: because of gro-wing interdependency and because of the ten-dency to handle complex models in a homoge-nous environment. The second reason is evenmore important because it is the answer to themarket pressure when it comes to control theengineering changes in limited time and budget.Figures 1 and 2 report details of floating unitsfor the offshore industry produced at SamsungHeavy Industry.

Geometric Construction in NodalConnectionsGeometric Construction are constructiontools belonging to SmartMarine 3D StructuralTask - Advanced-Plate Systems.The tools pro-vide interactive associative 3D graphics capabi-lity to ease and extend existing structuralmodeling capabilities, in order to solve plateplacement and modifications in different con-texts and specific usage.Geometric Construction are tools to exposeAPI to create complex constructions fromgiven geometry input and parameters.Following are some of the features of the tools:• support multiple member participation;• trim member to plate edge/face;

49Impiantistica Italiana • Anno XXII N. 2 marzo - aprile 2009

Rules-based andGeometric ConstructionConnections for theMarine Industry

Intergraph PPM is now re-focusing the design-for-productionof marine structures

Igor Juricic

Intergraph Italia LLC

After decades of experience in supporting the design of structu-res for all types of plants, Intergraph PPM is now re-focusing thedesign-for-production of marine structures. Typical offshorebeam constructions and typical shipbuilding stiffened platesconstructions have been approached in a uniform way withdedicated tools to satisfy the growing requirements of newmarine projects.

Automazione nelle connessioni di strutture per la cantieristica nava-le e l’offshoreDopo decenni di esperienza nel supportare la progettazione distrutture di tutti i tipi di impianti, Intergraph PPM sta ora rivisitan-do la progettazione orientata alla produzione di strutture marine.Strutture tipiche dell’offshore (travi e tralicci) e strutture navali(lastre nervate) sono state approcciate in modo uniforme con stru-menti dedicati per soddisfare le crescenti esigenze dei nuovi proget-ti di strutture galleggianti.

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• bound plate edge to plate edge;• plate shapes are driven by user defined con-struction parameters;

• establish connectivity between members andplates.

Side plates and continuity plates are the spe-cialty of Geometric Construction where theirshape changes following the angle of the inco-ming bracing in a robust and predictable way(figure 3).What makes the tools specific is the way togenerate the programming code i.e. the abilityto transform a set of Geometric Constructionsinto executables.

Geometric Construction Appliedto a Gusset PlateThis section illustrates the procedure to build amacro creating the support and the boundaries

for specifically shaped plate: a Gusset Plate atthe end of a member (rolled) in a nodal con-nection context.The whole procedure is divided in the follo-wing phases (figure 4):• support definition;• shape definition;• plate definition;• create macro (print graph).When the Geometric Construction sets arecreated by the sequence above the user cancreate a macro with the Print Graph functiona-lity (figure 5).The level of adaptability (Changes compatiblewith the Gusset Plate definition)of the macro is summarized as follows:• shape parameters yes• change bounding member cross-section #1

TBD• change bounding member cross-section #2

TBD• change bounding member #1 size yes• change bounded member #2 size yes• rotation along member axis no• move incoming member free end point yes• move member end point yes

The created program is referenced by thegiven macro entry in the catalogue and as suchit is made available to all the designers sharingthe project, to be replayed in the same context.The end-user browses the catalogue and choo-ses the macro, then selects the pertinent inputs(members systems); the macro is placed andcommitted, then the user places a plate systemusing the outputs of the placed macro (sup-ports, and boundaries).The procedure can be applied for other shapesof the Gusset Plate, as shown on figure 6.The Geometric Construction interactive pro-gramming allows for :• quicker development for modeling;• better debugging due to granularity of theinput;

• clear association log identifies failing seman-tics;

• modular implementation (from simple tocomplex nodes adding macros);

• rapid evolution of the end-user modellingtools.

Stiffened Plate Connections (Joints)The Stiffened Plate Connections illustrated inthis section belong to the SmartMarine 3DStructure – Bracket Plate System.The modelingtasks are following the design workflow fromthe early-stages to the production. The tasksare named:• Molded Forms;• Structural Detailing;• Structural Manufacturing.

50 Impiantistica Italiana • Anno XXII N. 2 marzo - aprile 2009

Rules-based and Geometric Construction Connections for the Marine Industry

Fig. 1 - Detailsof floating units forthe offshore industryproduced at SamsungHeavy Industry

Fig. 2 - Details offloating units for theoffshore industryproduced at SamsungHeavy Industry

At any stage there are different rules that aregoverning the design.Molded forms rules control how tripping stiffe-ners, brackets, bracket flanges, and profile knuc-kles are placed.Structural Detailing rules solve the penetra-tions by clips or collars, add the edge and thecorner features, manage the endcuts to theprofiles etc.The Detailed Design begins when the early-stage design goes through the detailing process.The detailing process trims the parts to theirfinal 3D shape, and creates assembly connec-tions in the way of the logical connections crea-ted by the topology in the placement process.The assembly connections are triggering theentire rule-based modeling process.Depending of the relationship between twoobjects (bounded or penetrating) the comple-te detailed solution with child features is gene-rated. The newly created features can subse-

quently trigger other rules with the placementof corresponding new features.Rules are written to control customized refe-rence data; each set of rules is delivered as aVisual Basic project which can be customized.



Fig. 3 -Typical nodal connections modeled with Geometric Construction

Fig. 4 - Support, shape and final plate definition

Fig. 5 - Portion of the VBcode generated by theprint graph functionality

Fig. 6 - Reused Gussetplate macro in similarcontext



VB rules control the output by:• analyzing connection and boundary cases;• accepting user input;• selecting default features;• controlling parameter output to size the fea-ture.

Rules control how and when the StructuralDetailing objects are used in the Model.Structural Detailing rules place the followingobjects:• Assembly and Physical Connections;• Brackets;• Clips and Collars;• Edge, Corner and Sketched Features, Slotsand Chamfers;

• End Cuts (Free and Constrained);• Edge Treatments;• Welds.Other data (Reference Data), like profile cross-sections and materials (types and grades) arepart of the catalog, and do not use rules.

Rules-Based Design Applied to the Bracket PlateSystemThe Bracket Plate System represents a typicalconnecting element between Stiffened Plates; itcan be stiffened (as any other plate), penetra-ted by stiffeners on the bounding structure andsplit with seams.A Bracket Plate System is sup-ported by a plate along one of its edges andsupported by profiles or plates along its otheredges (figure 7).The supports are used to defi-ne the plane of the bracket plate system as wellas its boundaries. The first two supports mustintersect in a manner that allows the plane tobe defined. Bracket orientation is driven by theorientation of one of the supports, a profilewhose web is used to drive the orientation, ora plate whose plane is used to drive the orien-tation.Following are the necessary steps to create andcustomize a Bracket Plate System:• Definition of the Bracket Symbol (addingseparately the Flange Symbol if this is thecase);

• Definition of the Tripping Bracket OffsetRules (when it’s necessary to re-position theBracket System from the given plane definedby the connecting elements);

• Bulk-load of Bracket’s Definition Data (plusoptional Flanges and Tripping Bracket OffsetRules) to the Catalog.

Each type of bracket requires the definition ofa Part Class and the related 2D Symbol.The definition Parameters must be loaded intothe catalog.For a 2-Support Bracket the Parameters arethe Height, the Width, the two Noses, oneRadius in case of a curve on the bracket edge;a second Radius for the Scallop in the way ofthe 2 supports intersection and the Lap distan-ce to cover the case of a bracket overlappingthe support(s).There is a powerful Symbol 2D Environmentsupporting the definition of all the 2D Symbols;the environment is allowing the definition ofthe constrains that are critical to proper sym-bol behavior (figure 8).A spreadsheet is containing the necessaryinformation to be loaded into the Catalog, i.e.the Selector Rules, the different Parametersmatching each type of 2-Support bracket, theNames of the Symbol files and of the DefinitionRules.The Bracket Plate System can be placed indivi-dually, where necessary, at designer’s discretion(figure 9); but the real power of the Rules-Based Design is implying the automatic place-ment of additional objects following theCompany preferred solutions (standards orbest-practices).In the case of a stiffener bounded by the flangeof another stiffener (belonging to a different

Fig. 7 -Typical bracketsin a stiffened plateconstruction



Plate System) the resulting AssemblyConnection can generate automatically someedge and corner features and create a slot,a clip, a 2-Support bracket and all the welds(figure 7 central).The Rules-Based Design as it is deployed inMolded Forms and Structural Detailing tasksallows:• faster and better detailing;• focusing the design intent;• skipping the repetitive job;• applying company standards whenever appli-cable (by the rule);

• more homogenous and consistent dataflowto production;

• selection rules (reduced skill level required).

Managing Changes and Re-useEssential in both described cases it is the crea-tion of associative relationships among the ele-ments concurring in the generation of the con-nection. The associative relationship is the pre-requisite for the “smart” change and re-use ofeach solution. In both cases the system is expo-sing the relationship to the end-user(WorkSpace Explorer in figure 3 - right). TheDesign changes are facilitated by the fact thatlow level details that can be inferred from thedesign and are automatically computed whene-

ver necessary.Following the different nature of the “beams”and “stiffened plate” structure the typical causeof modification it is also different:• Modified bracing angle (axis orientation orposition for members);

• Modified supporting Plate System (surfaceshape or position for stiffened plates).

It is the associative relationship that enables:• All the connections based on GeometryConstruction to re-compute automaticallyre-running the macros and interpreting thenew conditions;

• All the connections based on rules to re-compute since the rules will automaticallypropagate the effects of the modifications.Asif the plates coming together in the AssemblyConnection are modified, the rules will runthrough the selection process again. In casethat it is the Hull to change and that the shipis already far into the design cycle the chan-ge would cause the re-compute of a massiveamount of already detailed objects.

SmartMarine 3D structural tasks embed a high-level, abstract definition of the design that notonly captures the geometric result, but thedesign intent. When this feature is combinedwith powerful tools to describe the productstructure (where “structure” means “arbore-

Fig. 8 -The 2D graphical symbol and the spreadsheet with relevant data for the catalog

Fig. 9 -The way a2-support bracket isselected in the catalogand in a 3D view

scence”), and user-friendly ways to defineaggregations of objects (topo)logically linked; itresults in and permits efficient reuse of thedesign within the model.There are two high-level commands in MoldedForms performing “smart” copy/paste:• The Copy Similar, that replicates major por-tions of the model with the ability to auto-matically update the replicas as changes aremade. The best example comes from theshipbuilding industry: define a transverse bul-khead in a mid-ship area (including profilestiffeners, brackets, seams, openings, etc) andcopy the bulkhead to another transverselocation (outside the mid-ship area as well);

• The Copy Symmetry, that replicates portionsof the model based on symmetry. For eachsymmetry family of objects a coordinatesystem is selected.Again in the case of a ship(figure 10 right) the Copy Symmetry is per-formed across the longitudinal centerlinesymmetry grid plane. The Copy SymmetryFamily consist of groups of structure on boththe port and starboard sides of the symme-try plane. One group is reflected about thesymmetry plane to the other group.

In addition to the described reuse of designthere is the possibility to store the aggregatedobjects into the Catalog and perform multiplesubsequent “copy/paste” within the same pro-ject or within a group or projects sharing thesame Catalog.The re-use of the same design may result in adifferent detailed model since the boundaryconditions may be different.The benefits of efficient reuse of design aremultiple:• Standardization of complete functional solu-tions (rather than details);

• Faster and safer design;• Shorter delivery time;• Better and Faster materials estimation;• Preserved Company know-how;

• Flexibility with human resources (unevenlyskilled designers producing comparableresults).

Feeding ProductionIn spite of the different tools and workflowsapplied in the modeling phase (Molded Forms)all the created objects are equally made availa-ble for the detailing and manufacturing phases.The objects are also made available to thePlanning task for production planning andassembly hierarchy definition (once the attribu-tes are assigned the assembly hierarchy is ana-logous to a manufacturing bill of material thatcan be considered the specification of how tobuild the structure assemblies and theirsequence).The Structural Detailing objects aregenerated using the information inherited fromthe Molded Forms System.Detailing uses the parent system’s properties,such as thickness, continuity and molded con-ventions, to create parts containing neat, fullydefined geometry, including edge and cornerfeatures, chamfers and bevels.The associative relationship that greatly sup-ported earlier modeling phases is having animportant role in the detailing phase as well.The Assembly Connections are created auto-matically as children of the Logical Connectionsand the Physical Connections are created auto-matically as children of the AssemblyConnections. It is at the level of PhysicalConnections that theWeld and Bevel informa-tion are stored.The Structural Manufacturing task is addingmanufacturing-specific information to the detai-led parts and also creates supporting partssuch as pin-jigs and templates.Manufacturing data output is Rules-driven byuser-defined Visual Basic rules. As each manufac-turing plate (or profile) is extracted from thedetailed part, rules control how the object is pro-cessed i.e. distorted, featured and annotated.



Fig. 10 – IGCC-MeOH –COE case vs. costoof coal



Different set of options controls the plateorientation and marking directly from the rule.To summarize the provided process informa-tion:• shrinkage;• marking lines and text;• fabrication and assembly margins;• bevels and welds.Figure 11 shows T and Butt Weld preparation.Figure 12 shows examples of outputs related toa nodal flat plate.

The manufactured part relies heavily on theresult of the rules that were run at the detailinglevel. Bevel data is taken directly from the phy-sical connections, If a design modification forcesa change to the bevel data, the manufacturingpart is notified that a change was made, and itis marked as out-of-date.The user can approve the update to the manu-facturing data, and send the update to the pro-duction-planning system.The XML files, fully describing the piece parts

Fig. 11 -Weldpreparation

Fig. 12 - Marking linesand XML output



can be directly sent to the production-planningsystem.Before finalizing the file the information, theXML is parsed through the Adaptor.The Adaptor is a user-defined rule which parsesthrough the default XML schema and allows tomake replacements, modifications and deletionsof entries before (excerpt in figure 13).In case of demanding workshops or outsour-cing specific needs, various drawings, sketchesand other old-fashioned deliverables can begenerated by the system automatically.

ConclusionsCurrent economical situation is stressing theneed to manufacture the offshore plants (ofany kind) at the fastest time with reducing bud-gets. Single vertical CAD/CAM/CAE applica-tions, even if very efficient, are not enough toremain competitive on a market that is renownas a high-tech and top quality.

The interoperability among all the applicationsinvolved in the various phases of the project i.e.modeling, detailing, planning, manufacturing,material management is of continuously gro-wing importance.The aim in this article is at a single vertical 3DCAD application, the Structural one, where thetwo major streams in the marine industry (the“beam” and the “curved plate”) are required toco-exist and co-operate more than ever before.The goal is to keep the peculiarities of eachconstruction type while maximizing the com-mon terms in the design, the materials procu-rement, and the manufacturing technology.Thepaper focuses the two different ways to createtypical connections allowing easy placementthe first time and automatic re-computing incase of changes.The Geometric Construction and the Rules-based design are both capturing industry andyard’s best practices, speeding up the designprocess and reducing mistakes and rework thussupporting the challenges of the advanced off-shore industry. ■

References[1] Cochran K.: Rule-based Ship Design - ICCAS XIII,

Portsmouth, UK, September 2007[2] Duparcmeur Y.L., Patience R., Butler J.: Experienced

Marine Design and Data Use - ICCAS XIII, Portsmouth,UK, September 2007

Igor Juricic è laureato inIngegneria Navalmeccanicapresso l’Università di Zagabria.Ha iniziato la carriera comeResponsabile implementazioneapplicativi impiantistici alBrodogradiliste Uljanik di Pula(Cantiere Scoglio Olivi di Pola). Èquindi stato nominato IndustryConsultant e poi Project

Manager per l’area AEC (Architectural, Engineering andConstruction) presso la Computervision Italia SpA.Dal 1998 al 2005 è stato Responsabile vendite e supportoper la Tribon Solutions, produttore di software e soluzioni dedi-cate esclusivamente alla cantieristica navale.Dal 2005 è Responsabile Business Development Marine perl’area EMIA (Europe, Middle-East, India, Africa) di IntergraphItalia LLC (Divisione PPM).

Fig. 13 -Typical “beam”construction comparedto a “transition”structure

rules-based and geometric construction connections - intergraph

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