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    POSEIDON NDContents

    POSEIDON Tutorial 1

    POSEIDON ND Tutorial

    1 Introduction 3

    2 A Midship Section - fromConcept to Sizing 6

    2.1 Design Parameters and Concept Sketch 7

    2.2 Principal Dimensions and Material 9

    2.2.1 Input of the Principal Dimensions 9

    2.2.2 Material definition 10

    2.2.3 Storing the Project 112.3 Frame Table 12

    2.3.1 Generation of a Frame Table 12

    2.3.2 Changes in the Frame Table 14

    2.4 The Wizards of POSEIDON 15

    2.5 Modeling of Longitudinal Members 17

    2.5.1 Definition of the Frame Table (Y and Z Dir) 17

    2.5.2 Definition of Geometry and Topology 18

    2.5.3 Plates, Stiffeners and Holes of Longitudinal Members 23

    2.5.4 Arrangement of Transverse Stiffeners on Longitudinal Members 36

    2.5.5 Arrangement of Transverse Girders on Longitudinal Members 38

    2.6 Modeling of Transverse Members 40

    2.6.1 Cells 402.6.2 Transverse Members 46

    2.7 Design Criteria or Loads 53

    2.7.1 Tanks 53

    2.7.2 Design Criteria Stillwater Bending Moments and Shear Forces 57

    2.8 Sizing of a Transverse Section 59

    2.8.1 Sizing of all Members at Frame 154 in accordance with the GL Rules 59

    2.9 Permissible Stillwater Values 62

    2.9.1 Stresses for Deck and Bottom Structures 62

    2.10 Assessment of the results of a Transverse Section 63

    2.10.1 Correction of the Transverse Section 63

    2.10.2 Duplicate calculations in the GL Rules program 66

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    2 POSEIDON Tutorial

    3 Generation of a Further Transverse Section 68

    3.1 New shell description at Frame 68 and 76 683.2 Automatically generated Frame Shapes 69

    3.3 Definition of a cross section with new structural information 70

    3.4 Fitting the Plate and Stiffener Arrangement to the changed cross section 72

    4 A Transverse Bulkhead at Frame 76 75

    4.1 Description of Bulkhead components 75

    4.2 Geometry of Cells for Bulkheads 77

    4.3 Plate Arrangement 78

    4.4 Stiffener definition on a bulkhead 79

    4.5 Definition of girders on a bulkhead 81

    5 Generation of a FE - Model 825.1 Abstract 82

    5.2 Parameters of mesh generation 83

    5.3 Boundary conditions 84

    5.4 Definition of the loads to generate 85

    5.5 Mesh generation in longitudinal direction 86

    5.6 Start the model generation 87

    6 A Bulker example 89

    6.1 The Wizard for Bulk Carrier 89

    6.2 Built-up Web Frames and Transverse Girders 90

    6.3 Decks with cargo. 93

    7 Input of a Transverse Sections without a Frame Table 94

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    POSEIDON NDIntroduction

    POSEIDON Tutorial 3

    1 Introduction

    The purpose of this tutorial is to present a method of using POSEIDON ND accompanied by examples.To this end, the individual work steps and inputs to complete the given tasks are presented.

    The user is led through the individual program sections and can easily understand the solution to thetasks. There are many cross references to the Reference Manual and to the Online Help function thatclarify the various input alternatives.

    At the beginning of each section of the tutorial the problem to be solved is described. Furthermore theprerequisites from previous sections which are necessary for its solution are presented.

    The POSEIDON ND TreeView reflect, in its order, the fundamental work steps.


    Please follow the advice for the configuration of the POSEIDON ND program, which is to be found inthe POSEIDON ND User's Guide, in order to print POSEIDON ND files, properly install the examplefiles onto your hard disk and to use the individual settings for colors, typefaces, etc.

    POSEIDON NDs Online Help may be invoked at any point within the program using the F1 function

    key or the 'Help for active view'-Button . The help description, which corresponds to the currentdisplay, will be shown.


    For a direct printout of the actual window, please use the Print-Button . The print command can be

    used in all POSEIDON ND displays.

    Note: If you use thePrint Preview Button ,the printer output will be displayed on the screen.Here you can set your own individual settings for printer-and page layout.

    Graphical output

    An active preview plot window is available in most POSEIDON sections.

    Note: By clicking the right mouse button on the plot preview window, you can choose the printcommand or the print preview command.

    Use the plot button to view all graphics on the screen in a separate window. By pressing 'p' on thekeypad, the actual content of the plot window will be send to the printer.

    Plot all plates and profiles, for example, in Section Hull Structure, Longitudinal Members: PlateArrangement. There, you have additional control over determining what is to be plotted.


    POSEIDON ND is using WindowsTM

    standard functions. It is possible to use the commands cut, copy,paste in all child windows by clicking the right mouse button or using the corresponding buttons

    of the toolbar.

    A star in the left column of the input grids marks a new input line, containing proposals. A pencil

    marks a line in edit mode. A plus marks a line of a 'Super-Grid'. By clicking the plus you get thesecond input level of this grid. (see: definition of 'Functional Elements' for example)

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    4 POSEIDON Tutorial

    Figure 1: TreeView

    How to use this manual

    The experienced user may possibly find the descriptions in the individual chapters to be too detailed.

    Therefore, a short instruction of the work steps to be followed is given in the text lines marked with an.

    Several definitions and conventions, which are frequently used within the tutorial, follow:


    Section. The sections of POSEIDONND are shown by folders in theTreeView on the left part of themain window. A selection hasto be made in order to reach

    the actual input display. Thisprocess is described with thehelp of sections. So theexample: Switch to Section2.1.1 ' Wizards! TransverseSection ! Container Ship' 'means the selection of folderno 2 in the main-tree and,following that, the choice offolder no 1 in the sub-tree.


    Italics Inputs, which the user has tomake, are printed in italics.

    Frame No Name of a column or inputfield

    Summary of the inputs described in the followingsection.

    The tutorial describes the typical procedure for sizing a container ship in accordance to the GL Ruleswith the help of POSEIDON ND. The generation mechanism of POSEIDON and the various inputtechniques are introduced. It is shown how the sizing can be accelerated considerably by workingefficiently with POSEIDON. It is recommended that the users themselves practice using the computerand follow the work steps, which are given in the tutorial.

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    POSEIDON NDIntroduction

    POSEIDON Tutorial 5

    Figure 2: POSEIDON ND main window

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    A Midship Section - fromConcept to Sizing POSEIDON ND

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    2 A Midship Section - fromConcept to Sizing

    This chapter describes the modeling and the sizing process of a midship section.

    The process is subdivided into the following individual steps:

    concept sketch for a midship section,

    input of the characteristic ship data / principal dimensions,

    generation of a frame table in the ships longitudinal direction (X axis),

    geometric and topologic description of the shell, inner bottom, bulkheads, decks, girders, transversemembers, etc. for various frames,

    arrangement of plates, stiffeners and holes on these Functional Elements,

    input of the design-loads, which have an influence on the sizing of plates and stiffeners inaccordance with the GL Rules (cargo static, dynamic, tanks with corresponding medium etc.),

    input of the permissible design bending moments and shear stresses,

    iterative sizing in accordance with the GL Rules, varying loads and corrections on members.

    The complete input described in this tutorial is also contained in the file TUTOR_ND.POX that isloaded on the POSEIDON ND CD-Rom.

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    2.1 Design Parameters and Concept Sketch

    ProblemCollection of the characteristic ships data, which are necessary for the sizing of the transverse section.


    This step does not require the prior completion of any POSEIDON ND program section.

    In this example the ships characteristic dimensions and design parameters are as follows:

    Ship Type: Container Ship CONTEST Class: 100 A5 Germanischer Lloyd

    Lpp: 230 m

    LwL: 234 m

    B: 32,25 m

    H: 18,3 m

    T: 13,5 m

    TB : 6,6 m

    cB : 0,65

    V0 : 23 kn

    Floor spacing: 3.060 mm

    Transverse frame spacing: 765 mm

    The abbreviations conform to the syntax in the Germanischer Lloyd Rules, Part 1 Chapter 1. For moreinformation call the Online Help for this section.

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    For the first pictorial representation of the midship section, a concept sketch has been made up.

    Figure 3: Concept Sketch of a Ship design

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    2.2 Principal Dimensions and Material

    ProblemInput of the principal dimensions, allocation of a project name, saving ofthe input in a file.


    POSEIDON is individually configured (see the Installation Manual).

    2.2.1 Input of the Principal Dimensions

    Switch to Section 1 'General' and enter a project name, project description and the Principal

    Dimensions according to the values given above.

    After starting POSEIDON, choose in the TreeView Section 1.1 General Data.

    You see a tabbed form for project data, principal dimensions, additional principal dimensions in case ofice class and a description of the waterline in damage condition. Please enter a project name and theauthors name. The description field makes it possible to give a detailed description of the project.Choose the second tab 'Principal Dimensions' and enter the values given above(see Figure 4).POSEIDON ND automatically calculates the GL scantling length L. In our example inputs for ice classand for waterline of damage are not necessary here. If, for example, entries are made in classificationsymbol E2 for ice strengthening, the formulas for ice strengthening in accordance with the GL Rulesautomatically flow into the scantling of the transverse section. You can find more information on thistopic by calling the Online Help function with F1.

    Figure 4: Input mask for Principal Dimensions

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    2.2.2 Material definition

    Check the default material number

    Choose in the TreeView the Section 1.2 materials and familiarizeyourself with the definitions of thematerial numbers. It is possible to define your own material numbers also at this point.

    Figure 5: The pre-defined material values

    When displaying the section 'Show with plate thickness' ( by using the plot button ) or the ToolTipsof the preview-plot-window (by moving the mouse pointer on a Functional Element) the three primary

    materials are indicated by stars. Members with Mat.No.1 contain no stars; members with Mat.No. 2and 3 contain 1 and 2 stars, respectively. Higher material numbers (user defined materials) areindicated by the # sign. This display convention allows the user to identify graphically areas of the hullusing higher tensile materials.

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    2.2.3 Storing the Project

    Save the data and reload the data.

    Now, save your first project by clicking the save-button in the toolbar. POSEIDON ND launches aWINDOWS

    TMdialog box where you have to enter the path and the name of the project file. Save the

    project under the name MYEXAMPLE.POX. If you repeat this command later, POSEIDON ND saveyour work direct under the given project file name. Please use the 'Save As' command in the Filemenu, if you want to assign a new project file name.

    Figure 6: POSEIDON ND Filepull down menu

    To reload a project file, please use the open command in the Filemenu or the LoadButton in thetoolbar.

    Advice: If you start POSEIDON ND, the latest stored project file will be loaded automatically.

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    2.3 Frame Table

    ProblemGeneration of a frame table in the ships longitudinal direction.


    The principal dimensions exist in POSEIDON ND, Section 'General!General Data'.

    2.3.1 Generation of a Frame Table

    Switch to Section 1.4 and enter the aft perpendicular (frame 0, offset0 mm) in the frame table.

    Choose the Section 1.4 Frame Table (X-Dir) of the TreeView of POSEIDON ND. The forwardperpendicular resides at frame 300+500mm. Check the entries of the aft perpendicular in the head ofthe table.

    * Choose 'AFT' in the field 'Keep PP' and check the entry of the field 'at Frame' If the value is not0, please enter 0. The calculated forward perpendicular should be frame no. 230 now.

    From the entries for the aft perpendicular, the given frame spacings and Lpp, POSEIDON NDautomatically calculates the forward perpendicular and shows it in the grey shadowed field in the headof the window. If you know the position of the forward perpendicular it is also possible to enter theposition of the forward perpendicular. Then the aft perpendicular will be calculated by POSEIDON ND.

    The table is to be filled out with frame numbers from -9 to 302. The frame spacing is 765 mm.

    Enter in Line 1 of the frame table:Frame No.-9, Frame Spacing 765. Enter in Line 2 of the frame table:Frame No.302, Frame Spacing 765.

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    POSEIDON ND makes two input rows with a useful proposal available. Next, change the proposals of

    Frame No. 1 and overwrite this with -9. Next, overwrite Frame No. 2 with 300. Enter765for both

    Frame Spacings.

    Figure 7: Input mask for Frame Table

    Advice: POSEIDON does not extrapolate beyond the last frame number, therefore the highestoccurring frame numbermust be given.

    After concluding the input by leaving the last input row, POSEIDON generates the complete frametable. With this, the position of the forward perpendicular is also defined and the value of 300+500should be displayed in the head of the table.

    The program calculates both of the last two columns of the table. Xp-Coordinate fr. aft PP gives

    the spacing of the frame from the aft perpendicular. X/L contains the relative spacing of the framefrom the starting point of length L, which for its part is taken from the forward perpendicular to the aft(see Figure 7).

    With the 'toggle to all lines ON / OFF 'button of the toolbar, you can activate or deactivate thedisplay of a list of all generated frames. Use the scroll bars to scroll up or down through the table.

    Save your work using the pull-down menu File, Saveor the Save-button . The changes that followin the next section are not necessary input for our example; they serve only as further practice indealing with the frame table display.

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    2.3.2 Changes in the Frame Table

    The frame table can also be modified. For example, here is how to change the spacing to 750 mm inthe range between frame 3 and frame109.

    For this, first conceal the display of the generated frame list (toggle to all lines off ). Place the

    cursor on Frame No. -9 and twice insert, by using the F6function key, two new input lines. Overwritethe first generated input line in Frame No. with 3and the second generated input line in Frame No.with 110. Next, overwrite the Frame Spacing for Frame No. 3 with 750. Complete the input byleaving the edited line.

    Display the list of generated frames (toggle to all lines on ) and scroll through the new frame tableand check the results. Observe also that the position of the forward perpendicular has changed,because of the input of the new, diminished frame spacing, and that the forward perpendicular alsohas been newly calculated.

    Now, re-establish the original values. Highlight the row ofFrame No.3by placing the mouse pointeron the left grey column of the window and press the F5 function key or by clicking the right mousebutton to get the pop-up menu which show all possible commands (see Figure 8). Delete both rows, so

    that now only two rows exist, one with Frame No.-9and one with Frame No.300.

    Figure 8: Delete a row of the frame table

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    2.4 The Wizards of POSEIDON

    ProblemDefinition of a typical cross-section with the help of a POSEIDON-Wizard.


    The principal dimensions and the frame table have been entered.

    The built-in Wizards of POSEIDON allow much faster generation of the midship section than thestandard way of manually describing each functional element. For example a midship section of acontainer ship can be generated in a few minutes with the help of the Wizard. This generated sectionhas to be modified afterwards to reflect the design idea or the actual design in all details.

    The input displays of the wizards are largely self-explanatory. The input fields are described in online-help.

    Choose the Section 2.1 Wizards!Transverse Sectionin the POSEIDON ND TreeView. Choose Point1 Container Ship.

    As shown in the concept sketch the midship section should include a ballast tank and only 9 containers

    in the bottom layer. To change the number of containers in the bottom layer, overwrite the No. ofCont. in Y-/Z-Dir -parameter with 9;11 and complete the input with the ENTER key. Look at thegraphical output, a ballast tank is defined now.

    By clicking the OK button, a typical POSEIDON-description of the cross section is generated.

    Figure 9: Cross section wizard for Container Ships

    Advice:Notice that the Wizard always generates (and also overwrites) complete cross sections. Forthis reason do not use the Wizard to edit regions of a cross section.

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    2.5 Modeling of Longitudinal Members

    ProblemDefinition of the individual structural elements of the transverse sections and the description of thegeometry and the topology.


    The principal dimensions and the frame table have been entered.

    New feature: Frame Table (Y and Z Dir)

    A new powerful feature in POSEIDON ND is the possibility to define a frame table in y-z direction. Thenames of the longitudinal frames can be used as references in the description of transverse andlongitudinal members. The longitudinal frames are shown as horizontal or vertical dotted lines in a

    transverse section of the vessel.

    2.5.1 Definition of the Frame Table (Y and Z Dir)

    The Name of the longitudinal frame can have a maximum of 6 characters. The name must begin withup to four letters followed by a number. The number is necessary for the generation of frames.

    Choose the Section 1.5 in the TreeView. Overwrite the field Frame No. with 154. In our example, thename of the longitudinal frames will be L_0 up to L_n. Activate the grid cell Name by the mousepointer and use the proposal L_0 of the pull down menu (see Figure 11). Jump into the next grid cell

    No by using the Tabkey. Here you use the proposed 1 to get the definition of one longitudinal frame.

    Use also the proposed value 0,0 to define the spacing and the y-coordinate. The grid cell of the z-coordinate has to be empty for definitions of frames in y-direction. Choose P for the symmetry of thisframe, because it is defined in the center line of the vessel.

    Figure 11: Use of the frame table in y-z direction


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    The input of the next line is similar, but you have to change the name to L_1, the y-coordinate to720,0 mm and the symmetry to P+S. In the third line we want to define 12 frames. Change the

    name to L_2, the value ofno to 12, the spacing to 855,0 and the y-coordinate to 1440,0. Thepreview displays the actual defined frames. It is possible to highlight the defined frames in the preview

    window and POSEIDON ND shows a ToolTip containing the actual name and the actualcoordinate of the highlighted frame. With this function you have fast access to the name and thecoordinate of the last generated frame. With the all lines oncommand, you can see the names of allgenerated frames. The complete input of the frame table is shown below in Figure 12: .

    Figure 12: Frame table in y-z direction

    Save your work and close the frame tablewindow.

    Advice: Files containing the definition of a 'frame table in y and z Dir' do not work correctly with olderversions of POSEIDON!

    2.5.2 Definition of Geometry and Topology

    Choose the section 3.1.1 'Hull Structure! Longitudinal Members!Functional Elements. In this inputdisplay, the so-called Functional Elements, which are involved in the transverse section, are defined.

    POSEIDON ND's Functional Elements describe the geometry and the topology (i.e. the connectionbetween the elements) of the longitudinal members of a ship steel structure. They are entirelyindependent of the plate arrangement or a possible finite element grid. For example, the entire shellshape is defined as one Functional Element, just as the entire inner bottom is one other element.Functional Elements connecting to other Functional Elements must be described by naming theconnecting members (reference), as is demonstrated in the following example.

    In POSEIDON ND, a Functional Element is identified by its abbreviation (name of the Short Cut),which is always used and recognized in other program parts.


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    POSEIDON ND interpolates geometric information between frames. If, for example, a FunctionalElement is described at frame 100 and labeled with the attribute F or F+A and if the same FunctionalElement is also defined at frame 130 and labeled with the attribute A or F+A, then the geometry of the

    Functional Element will be interpolated between these two cross sections. That means:

    F : The geometric information is also valid for frames located further forward and willbe utilized for interpolation.

    A : The geometric information is also valid for frames located further aft and will beutilized for interpolation.

    F+A : The geometric information is also valid for frames located further forward andfurther aft and will be utilized for interpolation. Generation of the Functional Element SHELL

    Switch to Section 3.1.1 and generate the Functional Element SHELL atframe154, Attribute F+A.

    Establish your first Functional Element. Activate the grid cell Func.Ele and use the proposal SHELL ofthe pull down menu. Using the Tabkey or the mouse pointer activate the next column Frame No. andenter 154. and accept the standard value of F/A.F+A means, that the shell will be interpolated at allcross sections (forward and aft) between the definition at frame 154 and the next direct definition.

    Accept also the standard ofP+S for symmetry and the y and z-coordinates (0,0/0,0).

    In the right hand column LT of the line, a 1 for a straight or a 2 for a circular connection (e.g.: bilgeradius) of the shape points has to be entered. Accept the 1 and complete the input by leaving theedited line. Now the second line is activated and you have only to change the y / z-coordinates and the

    line type. If a value remains constant from one line to the next, that field should be left empty. Thedefinition of the Functional Element SHELL is shown in Figure 13.

    The description field can be used for a any description of the Functional Element.

    Enter the Shape Representation of the SHELL according to the following figure.

    Figure 13: Shape definition of the Functional Element SHELL

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    The preview display you get a visual control of the actual definition of the functional element .Try tohighlight the sections of the functional element by the mouse pointer and you will see the coordinatesin the ToolTip.

    It is also possible to use the Plotbutton to take a look at your complete shape representation forthe Functional Element SHELL. You will recognize the orientation of the SHELL description by thesmall, black arrow at the beginning of the shape. This orientation will later be the basis for thepositioning of the plates and the stiffeners on the Functional Element SHELL.

    Advice: Orient the Functional Elements from center line to outside and from below to above. Thissimplifies the overview for you. Symmetrical members intersecting the midship plane muststart at the symmetry-line (e.g. SHELL at Y= 0).

    By pressing the minusbutton now the rows containing the coordinates will be closed. Now enter the

    text description whole shell in the field Description. As previously mentioned above, Functional

    Elements may be referenced by means of your short cut. The term used here only serves the purposeof simplifying the distinction between the Functional Elements for you. Generation of further Functional Elements

    Definition of Functional Element IB at frame 154 with attribute F+A. For shape representation, refer tothe following figure.

    Establish the Functional Element inner bottom with the abbreviation Func.Ele. IB and the F/A

    attribute F+A by activating the last line beginning with the star . Overwrite SHELL with IBand enterthe following values:

    Figure 14: Shape definition of the Functional Element IB

    Constant coordinates have to be entered by a blank (the same value will be used as in the line before).To create an empty value (blank), choose the first line (empty) in the pull down menu which is available

    in the coordinate grid cells. This is automatically opened, if you press the arrow button of the activecell. This pull down menu contains references to all defined Functional Elements. The z-value L_21(reference to the y-z frame table) can easily given by highlighting the L_21 frame in the preview and aright click on the mouse. A pop up menu will be launched where you can choose the command: Setactual grid cell to L_21 (see Figure 15).

    Use the Plotbutton, to take a look at your complete shape representation for the Functional ElementsIB and SHELL.

    Press the minusbutton to close the rows containing the coordinates.

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    Figure 15: Use preview plot functions to define functional elements

    Enter the Functional Element DK_1, description weather deck, attribute F+A at frame 154. For theshape, refer to the followingFigure 16. (Note the usage of the SHELL for the description).

    Next, establish the new Functional Element with the description weather deck, the Short CutDK_1and the F/ AF/ AF/ AF/ A attribute F+A. Enter the following values in the input mask.

    Figure 16: Definition of the Functional Element DK_1 (main deck)

    Advice: DK_1 and IB are now connected with the functional element SHELL, marked by the redcolored circles. It is an advantage to use this style of description, because if the descriptionofSHELL changes, the deck (DK_1) and the innerbottom (IB) always remain attached to theSHELL and change their geometry automatically.

    You always have visual control of your actual input in preview window.

    Enter further Functional Elements.

    Now, by using the coordinates given below (see Figure 17), enter all other Functional Elements.

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    Figure 17: List of all defined Functional Elements

    The coordinates for the other elements are given below. By clicking on the arrow button of a gridcell, you get the pull down menu containing all existing functional elements.

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    POSEIDON Tutorial 23 View of the Transverse Section at Frame 154

    With the Plotbutton , you can view the results of your work. Choose Frame No.154and ShowGeometry /Topologyin the following dialog box.

    Figure 18: View of the transverse section at frame 154 with topologic connections

    The points shown in circles indicate that POSEIDON has realised a physical connection between theFunctional Elements at each of these points. Therefore, be certain to check that all physical elementconnections are marked with a circle.

    2.5.3 Plates, Stiffeners and Holes of Longitudinal Members


    In this section, the purely geometric/topologic description of the model is supplemented by thearrangement of plates and also by the description of stiffeners and holes on a Functional Element.


    At least one Functional Element exists at the frame.

    In POSEIDON ND the plates and profiles can be defined with or without given dimensions. If nodimension are given, a preliminary thickness (1.0 mm) or profile dimension (minimum dimension fromthe profile table) will be assumed. The required values according the GL Rules can be determinedduring sizing.

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    24 POSEIDON Tutorial Automatic Plate Arrangement for Longitudinal Members

    Switch to Section 3.1.2, plate arrangement at frame 154.

    Select the section 3.1.2 Hull Structure! Longitudinal Members! Plate Arrangement. In this inputtask the plates on the existing Functional Elements at frame 154 will be generated.

    POSEIDON ND offers the choice to generate standard plate and stiffener arrangement automatically

    or to copy such an arrangement from another frame.

    Enter in field Frame No. the value 154. If no input (empty list) for frame 154 has been given so far,

    activate the first grid cell Func.Ele and then press the magic button . Plates and stiffeners for allFunctional Elementswill be generated for the entire cross section.

    Figure 19: Input mask for plate arrangements

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    By default POSEIDON ND generates five plates for the SHELL (from keel to sheerstrake) and oneplate for all other Functional Elements.

    Advice: In order to arrange plates on a Functional Element automatically, the current frame has to bewell defined. That is, either it has to be described by explicit input, or it must be possible to

    interpolate it by means of the attributeF/A of other frames.

    Now, use the Plotbutton and activate the hook plate dim. In the dialog. Take a look at the transversesection you have just generated.

    Fitting the Plate Arrangement of the Shell Plating

    As an initial configuration, the automatic plate arrangement is very effective, however, it has to befurther refined and adapted to the design concept. Modifying the arrangement is the subject of thissection.

    All plates, which belong to the shell, carry the Short Cut SHELL. In order to achieve a better overview,you should describe the individual plates in greater detail with the help of Item. In our example, wename the first plate SHELL;FK(for flat keel) and all others as SHELL;A to SHELL;J.

    Flat Keel

    Overwrite the descriptionkeel with FK

    First, overwrite the description keelwith FK(flat keel).

    POSEIDON determines the starting point of the plate FK (BEGIN) directly from of the starting point ofthe geometry. Plate arrangements always have the same orientation as the geometric description ofthe corresponding Functional Element.

    A plate width of 900 mm is defined with B=900.0and, with that, the End of Plate is determined;POSEIDON ND "proceeds" 900 mm further along the geometry and so determines the endcoordinates.

    The moulded line is to the right as seen from the start point of the plate, so leave RIGHTas it is. Here,you can choose between right and left by using the pull down menu of the grid cell.

    Leave the field for minimum thickness t[mm] empty. The symmetry input P+Sis already correctly filledin, because our model is symmetrical.

    Material No. 1 is also appropriate. Compare it with the above given material table.

    The Design Criteria S corresponds on the consideration of shell load, in accordance with the GLRules. The relevant design criterion must be assigned to every plate. If you press the pull down menubutton, the following dialog box (see Figure 20) will be displayed, where you can choose between allpossible design criteria.

    Advice: if you use the standard naming of the functional elements (SHELL, IB, LB_n, LG_n, DK_n,CO_n) the relevant design criterion will be used by POSEIDON ND!

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    Figure 20: Dialog box of design criteria

    Your first plate has now been fitted to the functional element SHELL.

    Advice: The orientation of the plates on a Functional Element must correspond to the orientation ofthe geometric description of the Functional Element. Also, several plates have to bedescribed according to the order given by this orientation.

    Bottom Plating

    Overwrite the descriptionbottom withA andEnd of PlatewithB=3000.

    Insert further rows for the shell and overwrite the description withB, C andD.

    In the example, the bottom plating should be made of the plates "A" to "D".

    For the bottom plating, overwrite the description bottomwith A and End of Plate with B=3000.

    Highlight the line of SHELL;A and, with F6(New) or a right mouse click, generate a further input line forplate B. Overwrite A with B. Carry out the same for plates C and D.

    With AUTOas the starting point of each following SHELL plate, the end-point of the previous plate ofSHELL will be automatically fitted.

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    Bilge Plates

    Overwrite the Descriptionbilge with E andEnd of Platewith z=3800.

    The bilge strake is represented by plate E.

    For the bilge strake, overwritethe description bilgewith Eand End of Plate with z=3800. This time,you have used a Z coordinate value for the End of Plate. POSEIDON overwrites it with ;Z= 3800.0and calculates the required Y coordinate from the geometric description.

    Side and Sheerstrake Plates

    Overwrite the descriptionside with F andEnd of Platewith B=3000.

    Generate further lines from SHELL;F with the descriptions G, H and I.

    The side plates are described with a letterfrom F to I.

    For the side plate F, overwrite the description sidewith Fand End of Plate with B=3000.

    Highlight the line of SHELL;F and, with F6(New) or a right mouse click, generate a further input line forplate G. Overwrite F with G. Carry out the same for plates H, I and J.

    Overwrite the description sheerstrake with K, material no. with 3 and the minimum thickness with30mm.

    For sheerstrake plate, overwrite the description sheerstrakewith K.

    Material no. 3 is assigned to this plate (in accordance with section 1.2 Materials) and a minimum

    thickness of 30 mm. The end point ENDis already correctly filled in. POSEIDON calculates the end ofthe shape representation of the SHELL and uses these coordinates internally forEnd of Plate.

    The preview displays generated plates. Check particulary the plate butts. Highlight the plates by themouse pointer to see the ToolTipcontaining the name of the plate and the defined thickness.

    Advice: The plate description of a Functional Element (for example SHELL) frequently consists ofseveral rows. In order to ensure that plates always describe the complete FunctionalElement, the first plate of the element should always start with BEGIN and the last plateshould always finish withEND.

    Fitting of the Plates for the Inner Bottom

    In our example, the inner bottom plates are sequentially numbered from 1 to 4.

    OverwriteEnd of PlatewithB=3150, t[mm]with18 mm andMould. Linewith left of the plateIB;pl.1

    Plate IB;pl.1 lies opposite to plate SHELL;FK. Overwrite End of Plate with B=3150.

    In the field t[mm], enter a minimum thickness of 18mm. In the field Mould. Line, choose leftbyusing the pull down menu.

    Check the field Design Criteria and enterIBif there is no entry.

    Generate a new plate from IB.pl.1 and overwrite the description with pl.2 and End of PlatewithB=3150. Generate IB;pl.3 with the same data, and IB;pl.4 withEnd of PlateEND.

    For inner bottom plate pl.2, now insert a new line. For this, place the cursor on IB;pl.1 and execute theF6 (New) command. POSEIDON inserts a new line and assumes the values.

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    Overwrite the description pl.1 with pl.2and End of Plate with B=3150.Also generate a new line for inner bottom plate pl.3. The width should be 3150 mm as well.

    Use the F6 (New) command andoverwrite the description with pl.4and, select LB_2+50forEnd ofPlate. POSEIDON ND internally calculates the end coordinates from the geometric description.

    Fitting of the Longitudinal Bulkhead Plates

    OverwriteEnd of Plateof plate LB_1;pl.1 withZ=6800.

    The longitudinal bulkhead plates are named with digits from 1 to 5. The fifth plate (above) consists ofhigher tensile steel.

    The first plate LB_1;pl.1 starts with BEGIN (= beginning of the geometry) and ends at ;Z=6800.0.Overwrite the old values. If you imagine the end point of the plate as being the coordinate values Y ; Z,then you have now internally referenced the Y coordinate of the LB_1 shape representation and

    explicitly assigned the Z coordinate 6800 mm. This is useful, because, by doing this, you have placedthe plate butts on the shell plating and on the longitudinal bulkheads at the same height.

    The moulded lines for all longitudinal bulkhead plates are located left as seen from the start of the

    Functional Element; therefore, the entry leftin the field Mould. Line is already correctly filled in.

    Generate three more plates from LB_1;pl.1 and overwrite the description with pl.2 topl.4 andEnd ofPlatewithB=3000.

    Generate a further plate and overwrite the description withpl.5, theEnd of PlatewithEND, t[mm]with30 mm andMat.No. with3.

    For plates 2 to 4, insert a new line and enterB=3000forEnd of Plate

    for each.

    For plate 5, insert a new line as well and, select EndforEnd of Plate. The Material No. is 3 for highertensile steel and the minimum thickness is 30.0mm.

    Fitting the Plates for Deck 1, Deck2 and Deck6

    Change the data for Deck1 toDesign CriteriaWD, t[mm]40 mm, Material No. 3 and Moulded Lineleft.

    Check the data of Deck2 and Deck6 to Moulded Lineleft.

    For the plate assignment for Deck 1, enter the Design CriteriaWDfor weather deck as design load.

    Additionally, enter the minimum thickness as 50.0mm and the Material No. 3.The moulded lines for all three decks are located left as seen from the start of the Functional Element. Overview of the Plates for the Longitudinal Members

    Fit further plates according to the following table or the concept sketch. Save the file.

    Following, you will find an overview of all plate arrangements at frame 154. Now enter the data for theplates, which have not yet been fitted (particularly CO_1and CO_2and LG_0to LG_14), and comparethese with the concept sketch found at the beginning of the tutorial. As descriptions, the longitudinalgirders use the longitudinal frame number.

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    Check the results of your work by using the Plotbutton. Observe the placing of the stars behind thethickness values used to identify members with Material No.3.

    Figure 21: View of plate arrangement at frame 154

    Save your work. Arrangement of Longitudinal Stiffeners

    In POSEIDON ND you can define several stiffeners with the same spacing and of the same type in one

    input line. If one of the stiffeners is located at the position of an adjoining Functional Element, then thisstiffener will not be generated by POSEIDON ND!

    To find the input display for stiffeners switch to section 3.1.3.

    POSEIDON has already automatically generated a stiffener arrangement, together with the platearrangement, which you can modify.

    It is useful to use the new function of the ' frame table in y and z dir'.

    Stiffeners at the Shell Plating

    Switch to the display of the Longitudinal Stiffeners, (Section 3.1.3). Overwrite the Description 1 of the

    SHELL with1-2, Start of Spacingwith L_1, End of Spacingwithn=1, the Profile Type withHP,Moulded Line withMF and Material No. with3.

    Use the item indicator 1, for this row will describe the first stiffeners on the shell. In the column Startof Spacing (position of the 1st stiffener), Y or Z coordinates, or a reference to the geometry, will be

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    requested. Choose L_1. EnterEnd of Spacing with n=1.The stiffener type HPis already correctlyfilled in, otherwise the desired type can be chosen by the pull down menu. Leave the dimensioncolumns empty. The stiffeners should lie on the moulded line of the SHELL, with the profile bulbspointing towards mid-ship. Therefore, select MFby the pull down menu in the field Moulded Line. Theangle of rotation is to be given relative to the SHELL with R90.0degrees. The profile on the outer shellbottom should be of higher tensile steel and contain the Material No. 3. The stiffeners should bearranged on both sides and should contain the Symmetry Designation P+S.

    Advice: the value l should be 0, if transverse members (e.g. floor plates ) are defined. Foreconomized input it is possible to enter the distance of the transverse members here. Then itis not necessary to define the transverse members for the dimension procedure of thelongitudinal members. Attention: the given values in this field are used by POSEIDON ND inevery case, also if there are defined transverse plates with smaller or larger distances!

    The following figure shows how the angle of rotation and the position on and opposite to the moulded

    line and the orientation of the plates determine the orientation of the stiffeners. The value of the relativeangle of rotation is within the range from 0 to 180 degrees related to the orientation of the FunctionalElement.

    Figure 22: Orientation of stiffeners

    Highlight the line SHELL and create a new input line by pressing F6 (New). Overwrite Item with 3-13,

    Start of Spacing with L_3, End of Spacing with L_13anda with 0.

    Zoom the preview by pulling open a window with the left mouse button and observe how POSEIDONhas generated the stiffeners. Recognize, that the stiffeners of the SHELL which are located on theposition of the longitudinal girders, consequently will not be generated.

    Now, enter the remaining profiles on the SHELL and use, as Item-description, the numbering of thestiffeners (see Figure 23). The number of input rows depends on the number of changes in the

    stiffener types and stiffener spacing. For all stiffeners in the double bottom area choose MaterialNo. 3, which is equivalent to the use of higher tensile steel.

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    In the area of the uppermost plate (SHELL;J), enter the dimensions for the flat bar as 300*30.. Enter

    Material No. 3. With this, all of the stiffeners on the shell plating are completely described.

    Enter further stiffeners of the SHELL according to the following figure. (for a complete profile data table!see below )

    Figure 23: Input mask for longitudinal stiffener arrangements

    Stiffeners on Longitudinal Bulkheads LB_1

    Change the data of LB_1 in the same way as the stiffeners on shell.

    Overwrite the item description of LB_1 with 25-27. In the column Start of Spacing, Y or Zcoordinates are asked for. EnterL_25in this column. EnterL_27in the column End of Spacing andn=3fora. Select Type HPand leave the Dimensions empty. The stiffeners should be located on themoulded line of LB_1, with the profile bulbs pointing towards the bottom. Therefore, select MFin the

    field M. Line. The angle of rotation is to be given relative to LB_1 with R90.0degrees. The profileshould be made of normal tensile steel and contain Material No.1. The stiffeners should be arrangedon both sides and should contain the symmetry designation P+S. Enter the same definitions as used indefinition of SHELL stiffeners. (for detailed coordinates see the table below). Afterwards change theinput of LB_2.

    Stiffeners on Decks

    Redefine the input line ofDK_1. In the column Start of Spacing, enterL_18, in the column End ofSpacing enterL_19and n=2fora. Select Type FBand fill the field of the Dimensions with 400*50.Use material no. 3. Change the values of DK_2 and DK_6 according the table below.

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    Stiffeners on all oth er Function al Element s

    Use the 'Proposal Line' marked by the to generate a new input line in the display of the stiffeners.

    Select LG_14in the column Funct. Element. Next, overwrite the Item with 1-2. Let the stiffeners beginat z=575.0. The end of the stiffener position is adequately described by means of the number of

    stiffeners n=2and the spacinga. According to the concept sketch, enter650fora. Select the Type HPand leave the Dimensions empty. The stiffeners should be located opposite to the moulded line(opposite side) of LG_14 and with the view on the front side of the profile. Therefore, select OFby thepull down menu in the field M. Line. The angle of rotation is to be given relative to LG_14 with R90.0degrees. Thus, the profile bulbspoint downwards. The profiles should be of normal tensile steel andshould contain the Material No. 1. The stiffeners should be arranged on both sides and thereforeshould contain the symmetry designation P+S.

    Complete the entries for the stiffeners according to the following table.

    Generate further stiffeners according to the data in the following table. Save the data.

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    A view of the entered stiffeners can be produced by pressing the Plotbutton. Activate the hook profiledim. In the following dialog box. Zoom into the plot by pulling open a window with the left mouse buttonin the Plot Window (see the Reference Manual). Below, as an example, a zoomed view of the upperhull flange is shown. Zoom out by clicking into the window once.

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    Figure 24: Zoomed view of a transverse section showing profile description Hole Arrangement

    You have access to the input display for holes in section 3.1.4. Hull Sructure! Long. Members!Holes and Cut Outs.

    Generate four holes with a diameter of 600 mm in the longitudinal girders 5, 8, 11 and 14 at frame 154at half of the girder height

    Activate the first line.

    Use the pull down menu of the column Funct. Element, select LG_05. The Item-description can be1. In First F. No. and Last F. No. the definition range for the definition of holes can be entered.Enter154in both columns. In the column Description, the position relative to the Functional Element(or, alternatively, an absolute coordinate) and the hole dimensions are asked for. The standard value isY=.0;B=0.0;L=0.0. Overwrite it with F=.5;B=600.0;L=400.0(half of the girder height, width =400 mm,height=600 mm).

    The pre-setting ofSpacing is a. This means that the hole is defined on every frame in the definitionrange.

    Use the 'Proposal Line' and change the column Funct. Element with LG_08, LG_11 and LG_14.Check whether your hole display is filled out according to the figure.

    Figure 25: Input mask for hole arrangements

    Use the Plotbutton and zoom in to visualize your input.(see Figure 26: Zoomed view of a crosssection with holes)

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    Figure 26: Zoomed view of a cross section with holes

    Now, leave the plot window and save your data.

    Keep in mind that - in contrast to the manual input described here - the input of Functional Elements isgreatly simplified when using one of the wizards to generate a standard structure with few inputs. Thisstandard structure can then be modified with the techniques described here. Of course, direct input ofthe Functional Elements gives you the greatest possible flexibility.

    2.5.4 Arrangement of Transverse Stiffeners on LongitudinalMembers

    Description of a Transverse Stiffener on the center-line girder. Switch to Section 3.1.5.'TransverseStiffener Arrangement'. Generate a new row by using the values given in the following figure. Saveyour data.

    In POSEIDON the description of stiffeners which are located perpendicular to the ships longitudinaldirection is different than the description of longitudinal stiffeners. Therefore these transverse stiffenershave a separate input mask. They typically exist only on one frame or on a sequence of frames (forexample, every second frame). Therefore, such members may be described on several frames at thesame time, which do not have to directly follow one another.

    In order to enter the transverse stiffeners on longitudinal members, switch to the Section 3.1.5 'HullStructure!Longitudinal Members!Trans. Stiffener Arrangement'.

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    A HP profile should be placed on the center-line girder LG_00. The stiffener should be arranged onframe 43 up to frame 176 not at every frame.

    Select the Functional Element LG_00by using the pull down menu . Overwrite Item with SHELL-IB.

    In the column Start of Stiffener, Y or Z coordinates or a reference to geometry are asked for. Click

    the grid cell and select BEGIN; the position End of Stiffener is described with END, i.e. thestiffener extends over the whole length of the functional element.

    Enter43as First Frame No., 176as Last Frame No. anda;a;2ain the column Spacing (in whicha stands for the frame spacing). The stiffeners are now defined from frame 43 up to frame 176repeated in the order stiffener, stiffener, no stiffener, (stiffeners at frames 43, 44, 45, 47, 48, 49, 51...).

    The Type is already correctly filled out with HP; the Dimensions are to be left empty (POSEIDONchoose automatically the smallest profile from the active profile table). The stiffener should be locatedon the moulded line of the LG_00, with the profile bulbs pointing towards the front side. MFin the field

    M.Line is already correctly filled out. Compare your entries with those shown in Figure 27.

    Figure 27: Input mask for transverse stiffener arrangement

    Check the correctness of the definition by zoom in the plot view near the center line girder.

    Figure 28: View of a longitudinal with vertical stiffeners.

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    2.5.5 Arrangement of Transverse Girders on LongitudinalMembers

    Description of a Transverse Girder on the coaming. Switch to Section 3.1.6.'Transverse Girder'.Generate a new row by using the values given in the following figure. Save your data.

    The input of a transverse girder is similar to the input of transverse stiffeners. To enter a transversegirder on a longitudinal member, switch to the Section 3.1.6 'Hull Structure!Longitudinal Members!Trans. Girder' . Choose frame no. 76.

    A transverse girder used as a coaming stay should be placed on the coaming CO_1. The girder shouldbe arranged on frame 76 up to frame 180 at every 8


    Select the Functional Element CO_1 by using the pull down menu . Overwrite Item with STAY. In

    the column Start of Girder, select DK_1, the position End of Stiffener is described with CO_2.

    Fill in 76forFirst Frame No. and 180forLast Frame No., the Spacing is defined with 8a. Usethe following figure to define the next values hweb, bflg, tweb and tflg .

    The meaning is: height of web at Dk_1, height of web at CO_2, breadth of the flange at DK_1 andCO_2, thickness of the web and thickness of the flange.

    Figure 29: Input of transverse web frames.

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    Figure 30: Preview of the coaming stay.

    Compare your preview with the Figure 30 and save your work.

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    2.6 Modeling of Transverse Members

    The cross section oriented geometry and topology of a plate will be defined with the help of a so-called

    'cell'. Though cells are basic for the plate definition (each plate needs exactly one cell, which describesthe plate contour), the cell generation is completely separate from the plate definition because the cellsare also needed for the definition of tanks.

    For all structural components in the ships transverse direction, it is possible to define several of them(in a range of frames) with one statement. To simplify the input, there is also a generation hierarchy fortransverse structural components in POSEIDON. If several components use the same frame position,then a transverse member overwrites a girder and a girder overwrites a simple stiffener.

    2.6.1 Cells


    Definition of the geometry and the topology of transverse members with the assistance of longitudinalmembers.


    Main dimensions, frame table and the longitudinal members (long. Plate arrangement) have beenentered.

    Cells in POSEIDON are enclosed topological areas in a cross section. The description of cells byreference to Functional Elements offers the advantage that the geometry of the cell is automaticallyadjusted when the description of one of the Functional Elements (e.g.: SHELL) changes. Cells are not

    tied to just one frame. They are available at every frame at which the described contour constitutes anenclosed area. POSEIDON distinguishes between various types of cells:

    elementary cells are cells that enclose no other cells,

    permanent cells are defined by the user and may enclose several elementary cells. The user caneasily define permanent cells, by using the predefined temporary cells. Only permanent cells can beused for the description of transverse members.

    temporary cells are cells that are newly generated by POSEIDON for each actual cross section.Temporary cells are named CE_1 ... CE_n . This type of cell will not be listed in the input mask.They will be shown in the plot preview by moving the mouse pointer on it and serves the fast inputof the geometry description of permanent cells. Definition

    Now select the Menu Point 3.2.1 'Transverse Web Plates ! Geom. of Cells in the Section HullStructure. In this display, the cells for the description of the transverse members are created.

    Advice: Unfortunately we detected a bug shortly after finishing the release version 2. Please renamethe Short Cut 'CE_1' of the shown input line in the window 'Definition of Cells oftransverse web plates' to 'FL_2' at first! Otherwise a correct cell description is notpossible. This problem only occurs in version 2.000, if no permanent cells are defined in theactual file.

    * Please activate the input cell 'Short Cut' and overwrite 'CE_1' by 'FL_2'! (see Figure 31)Delete the description and change the symmetry criterion from S to P+S.

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    Figure 31: Rename the shown Short Cut 'CE_1'.

    POSEIDON shows a warning if you leave the changed input row. Please respond by pressing thebutton 'Yes'. (see Figure 32)

    Figure 32: Rename the Cell 'CE_1' with 'FL_2'. Press 'Yes'.

    The result should look like the following figure!

    Figure 33: Renamed Cell !!!! fixed bug of transverse cell description.

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    For an easier input, please change the properties of the preview plot window by a right mouse click onit. Choose 'Properties' from the shown pop up menu.

    Figure 34: Change preview plot properties by a right mouse click

    Choose the tab 'Cross Section'and change the option 'View on'from bothto portside.

    Figure 35: Preview plot Properties

    Next, close the plot properties window by a click on the cross .

    The plot properties of every preview window can be individual adjusted by the user.

    Now, it is possible to continue the input in the normal way. Therefore, please move the mouse pointeron the empty cell near the center line girder in the preview plot window. The active cell will be shownred colored and if you stop the motion of the mouse pointer, a yellow ToolTip shows the name of the'Temporary Cell'; here: 'CE_3'. Use the right mouse button to launch a Pop Up Menu and choose thecommand 'Insert permanent cell with geometry of CE_3' (see Figure 36). A new window will belaunched containing a proposal for the name of the permanent cell (see Figure 36). This name can begiven at the user's choice or he accept POSEIDON's proposal. Overwrite WF_1 (the meaning is:WebFrame_1) by FL_1 (Floorplate_1) and change the symmetry from P to P+S. (see Figure 37 andFigure 38) Then press the OK button. A new cell named FL_1 should be generated by POSEIDON.

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    Figure 36: Definition of permanent cells.

    Figure 37: Enter a name for a new cell.

    Figure 38: The new name FL_1.

    If a new cell is defined, POSEIDON ND shows the definition of the cell in the input table. The newpermanent cell FL_1 is described by the functional elements SHELL, LG_02, IB and LG_00 (seeFigure 39). It is possible to adjust the cell description by using other functional elements or coordinates.For example, please try to change the input IBto Z=900and see what happens in the preview. A half

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    floor plate will be shown. After that, please redefine the input to IBbecause we need a complete floorplate in the example.

    Figure 39: The Input to define the cell FL_1.

    Define the other three cells of the bottom area in the same way. The result are 5 permanent cellsnamed FL_1 up to FL_5.

    Advice: Please note that a symmetry designation for each Functional Element in the cell descriptionof FL_1 is given - which, in this case, is always set to P (port side) - although the cell issymmetric. Here, the symmetry designation of the Functional Elements is important only inspecial cases, for instance for the explicit description of cells crossing the line of symmetry.In such a case, the described Functional Elements which are located on the port side have tobe given and also those located on the starboard and, in particular, those which cross the lineof symmetry and run from starboard to port or the other way around.

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    It may be, that the input rows are not in order. POSEIDON ND gives the user the possibility to sort therows in the most input windows. Move the cursor on the header of the column 'Short Cut'. The cursor

    changes to a small black arrow. Now double click the left mouse button and the input rows will besorted.

    Figure 40: sort the input by the column 'Short Cut'.

    * Define the absent cells in the same way and compare to the list below.Save your work .

    Figure 41: Definition of cells of transverse web plates.

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    The display of your definition of Cells should look like the following, although perhaps in a differentorder:

    Figure 42: Overview of cells at frame 154 Automatically generated Cells

    Use the Plotcommand and have a look at frame 60, 140 and 150one after the other in the display'Show Transverse Member (Geometry)' and choose the hook 'perm. cells' only.

    POSEIDON interpolates and generates the geometry at frames which are not described andautomatically fits the cells for the transverse plates.

    2.6.2 Transverse Members


    This section describes the definition of transverse members and the arrangement of plates, stiffenersand holes.

    The transverse plates for the previously defined cells are to be created. The floors are located in therange of frame 76 to 184 symmetrical at every fourth frame. The docking plates are located at everyframe.


    The cells, which exist in the range of frame 76 to 184, are defined.

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    Switch to Section 3.2.2 and enter 76 asFrame No.. Define a new plate FL1:76, valid from frame42 to176. Select the cellFL_1 by using the pull down menu ofCelland define theSpacingwitha.

    In the Section Hull Structure, select the Menu Point Trans. Web Plates!Plates(Section3.2.2). In thisdisplay, transverse members are defined by Short Cuts. The geometry-description of a plate is donethrough the assignment of a cell.

    Next, press the 'Toggle on / off' button . This means that all defined transverse members areshown, independent of the frame on which they are defined. This setting is generally useful for theinput or changing of members, because it can otherwise occur that a component that was just definedwill not be displayed, since it is not defined at the current frame.

    Enter the name FL1:76 in the first input field Short Cut. This name is the name of the actual

    transverse floor plate. The default-setting in the field Itemis 1. The frame numbers indicate the rangein which the transverse component is valid. Here, enter 76 as First Frame No and 184 as LastFrame No .

    The assignment of the component to a cell is done by using the pull down menu of the field Cell.Select the cell WF_1 from the list that is offered. The molded line (ML) is already lying correctly withAftand material and symmetry designation can also be left as they are. Thereby, the component isgenerated symmetrically on both sides.

    The adjustment of the field Spacing follows as the last step. In this field, you define at which frames inthe range from First Frame No. to Last Frame No. the component is to exist. The default setting inthis field is a.This means that the component is defined on every frame from frame 76 to 184. Leavethe ain this field, which corresponds to a definition at every frame.

    The field Spacing is very flexible; it is also possible to enter complicated definitions. In this example,we will not make use of this, but, as needed, you can find exact instructions in the POSEIDONReference Manual or in the Online Help function.

    To define the other plates, overwrite the name of the Short Cut' and change the name of Cell in the

    proposed input row at each case. Change the Spacing from a to 4a.

    Define the transverse members according to values in the following table.

    Figure 43: Definition of transverse plates.

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    Compare your input values with the following figure again and save your data.

    Figure 44: Input Table 'Floors and Transverse Web Plates at frame 76.

    By entering individual frame numbers in the field Frame No above (e.g. at frame 77, 78 and 80), havea look at the components. You will see that the components are defined at the first and the last frameof the range and, additionally, at every fourth frame in between - also at frame 80. Check that thecomponent is not defined at frame 77and frame 78(only FL1:76 is defined at every frame), as well asat frame 79 (only every fourth frame). Depending upon the frame number, the definition line of thecomponent is either shown in the input table or not. Compare also the gray colored plates in thepreview plot at these frame numbers.

    The transverse stiffeners on LG_00, which are given in chapter 2.5.4, will be deleted by POSEIDONautomatically at the frame numbers, where a web plate is defined.

    Advice: When selecting cells by the pull down menu of the fieldCell, the temporary cells are shownas well. If such a cell is selected, POSEIDON ND automatically changes it into a permanentcell, names it WF_n and uses the proposed name in the Short Cut field. Change theproposed name into a new name after that. In order to clearly show POSEIDON's basicapproach, we have not used this "Abbreviation in this example

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    Switch to the section 3.2.3 'Stiffeners on Floors and Transverse Web Plates'. Use the 'Proposal Line' tochoose FL_1:76 from theShort Cutpull down menu. Enter LG_00+50 and SHELL+350 atStart ofStiffener, LG_02-50 and SHELL+350 atEnd of Stiffener, enter 2 atn, 1100 ataand FBat thecolumnType.

    Switch to the display ofStiffeners on Floors and Transverse Web Platesin Section 3.2.3.

    Use the pull down menu of the column Short Cut and choose FL_1:76to generate a new input line.The next two fields describe the starting point and the ending point of the stiffener. In this example, thefirst stiffener should run parallel to SHELL at a distance of 350 mm from LG_00 to LG_02. The values

    of the y-coordinates LG_00+50 (Start of stiffener) and LG_02-50 (End of stiffener). Now, giveSHELL+350for both fields of the column of z-coordinate (see Figure 45 ).

    A Functional Element (+ value) can be selected in all input cells for the description of the coordinatesof stiffeners.

    The field n gives the number of the stiffeners to be generated. Enter a 2 here. The field a defines thedistance between the 2 stiffeners. Use the value 1100. The molded line is already correctly filled outwith MR.

    In the field Type, select flat bar.

    Figure 45: Input of the first stiffener on a transverse web plate.

    Use the 'Proposal Line' and enter 2 in the columnItem, define the coordinatesStart of Stiffenerat270.0;SHELL+350,End of Stiffenerat270.0 ; IB-350,nas 2andaas 900.Choose FL_1:76 again from the pull down menu of the column Short Cut in the 'Proposal Line'.POSEIDON uses a copy of the previous line and you can change the values. Overwrite Item with 2,Start of Stiffener with 270.0;SHELL+350,End of Stiffener with 270.0;IB-350,nwith 2and awith900. The column a describes the spacing. Now you have created the stiffeners of a Cut Out of a pipe

    duct, which will be defined under section 3.2.4 later.

    Use the 'Proposal Line' and enter of Item as 3-4, Start of Stiffener at L_3;SHELL, End ofStiffeneratL_3;IB,nas 2andaas 855. Use connected in the columnEnd Connection.Choose FL_2:76from the pull down menu of the column Short Cut in the 'Proposal Line'. OverwriteItem with 3-4, Start of Stiffener with L_3;SHELL,End of Stiffener withL_3;IB,nwith 2and awith855. Now you have created two stiffeners with a spacing of 855 mm between each other. Choose C

    from the pull down menu of the column End Connection. This creates stiffeners on the web platewhich are connected to the longitudinals. The value lK will be considered in the calculation of thedimensions of the longitudinal stiffeners.

    Advice: The value lK reduces the free length of the longitudinal and will only be taken into account if

    the y-coordinate of the buckling stiffener is exactly the same as the y-coordinate of thelongitudinal!

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    Compare and complete your inputs with the following table.

    Figure 46: Definition of stiffeners on transverse members

    It is noteworthy that no frame range can be entered in this display. With the help of the Short Cut, thestiffener is assigned to the transverse component of the same name and automatically contains thesame range of validity as this one.

    Use the preview to have a look at your definitions, zoom in to see details. Save your work.

    Figure 47: Arrangement of the stiffeners on transverse web plates.

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    Switch to the section 3.2.4 'Holes & Cut Outs. Use the 'Proposal Line' and enter the name of theShortCutFL_1:76 and the dimensionsY=720; Z=0,5L; DY=800; DZ=1000; R1=200.

    Switch to the section 3.2.4 'Hull Structure! Transverse Web Plates! Holes and Cut Outs'.

    Choose FL_1:76 in the column Short Cut this is the name of the associated transverse component.For the definition of the dimensions of the hole, please enter the following data in the fields: Y-Pos:720;Z-Pos : 0,5L;DY: 800;DZ: 1000and R1: 200. With both of the two values DY = 800 and DZ =0,5L, the middle of the hole is defined. DZ = 0,5L denotes the center of the cell height. The twofollowing values establish the width (DY) and the height (DZ) of the hole. The value R1 define theradius of all four edges of the cut out, if the values R1, R2 and R3 are defined with 0. It is possible todefine different variants of cut outs. Please press the F1 function key to learn more about the definitionof different cut outs.

    Create new input lines for holes by using the pull down menu of the column Short Cut and enter thevalues according to the data in the following figure:

    Figure 48: Definition of Cut Outs on transverse web plates.

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    2.7 Design Criteria or Loads

    ProblemThe loads have an influence on the later sizing in accordance with the GL Rules. By using DesignCriterialoads are associated to plates and stiffeners.


    There are no special requirements.

    2.7.1 Tanks

    Choose the Menu Point Design Criteria in the POSEIDON Main Menu and select Tanks. In this inputdisplay, the tanks and their features are listed, matched with the sizing guidelines of the GL Rules.

    Please observe the following definitions and comments for describing the tanks:

    Tanks are described in the ships transverse direction by means of the limiting Functional Elementsof the longitudinal members. Tanks consist of one or more elementary cells as long as they areseparated by Functional Elements with holes. These are automatically recognized and numbered byPOSEIDON. In order to record the entire expansion of a tank, it is sufficient to enter only onecharacteristic elementary cell (known as a capture cell). If holes exist in the affiliated longitudinalmembers, POSEIDON automatically finds the correct closed cell. The cell names are also used inthe description of the transverse members.

    Capture cells have to be elementary cells. That means that they may encompass no other (internal)cells.

    Tanks are geometrically described in the ships longitudinal direction by means of the entry of arange of validity.

    Tanks lie either on the port side or starboard; the symmetry is not in use.

    Tanks should always be described with the help of capture cells and never manually, in order toavoid unnecessary errors.

    Switch to Section 4.1. With the help of the 'Preview Plot', generate permanent cells and Tanks.

    Your Tank No. 1 should be limited by the longitudinal girder LG_02, the SHELL, the deck DK_6, thebulkhead LB_2 and the inner bottom and be located on the port side.

    Please move the mouse pointer over the 'Preview Plot'. The temporary cells of the cross sectionshould be red colored if you move your mouse pointer to them. (if not, please set the preview plotproperties to 'default'). Activate the first cell beside the pipe duct and press the right mouse button.Choose 'Insert tank with cell CE_n' from the pop up menu (see Figure 50). The window 'Enter name fornew cell' will be shown. Rename the proposal TK_1 to TK_1P and press the OK button (see Figure51). The geometry of the 'Tank 1' is now defined by using the new created permanent Cell TK_1P(thecharacter 1 in TK_1 is generated by POSEIDON and is not associated with the tank number).

    Advice: If the tank is deleted, the cell TK_1P will not automatically be deleted along with it.

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    The default input of the Medium is Ballast. The other default values Rho, Frame No.Aft /Forward and Height of overflow will be calculated by the given main dimensions according the

    GL-Rules. Different values are only needed, if cargo tanks (Tanker) are defined. All values with 0,00(except pv! must be given for cargo tanks) will be calculated by POSEIDON.

    Figure 50: Choose the cell for the tank description.

    Figure 51: Renaming of the temporary cell.

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    Figure 52: The ToolTip shows the Tank No.

    Move the mouse pointer on the Preview Plot and see the name Tank 1 in the ToolTip, if you hold thepointer for a moment on the defined tank (see Figure 52).

    Generation of three additional tanks corresponding to the following figure with the help of temporary

    cells and determination of the geometric values of the tanks by using theCalc button .Save your data.

    For the entry ofTank No. 2 to 4 proceed similarlyanduse the input by the preview plot in the sameway as described before. Change the proposed tank cell names to TK_1S, TK_2P and TK_2S. Theresult is shown in the following figure.

    Check your completed display for the tanks with the Figure 53 and save your data.

    Figure 53: completed tank input at frame 154.

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    With the Calc command, you now have possibility to calculate the edgepoints and the expansion ofthe liquid surface at frame 154. According to the position of the "capture cell, POSEIDON setssymmetry description.

    Activate the first line of the input table and press the Calcbutton . A new window including a preselection of the tanks to calculate will be shown. You can change the data, but in our case press theOK button.

    Figure 54: Calculate Tank dimensions for the tanks 1 to 4.

    The tank dimensions for all tanks will be calculated. Compare your results with Figure 55 . The input ofa correct length is only needed, if partially filled tanks are to be calculated (cargo tanks).

    Figure 55: Definition of tanks at frame 154.

    The plates and stiffeners, which lie in or on Tank No. 1 to 4, will be calculated later during the sizing inaccordance with the GL Rules with the design loads for tank structures. The load assignment happensautomatically!

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    Figure 56: Closed cells generated automatically at frame 154

    POSEIDON has recognized the holes in the longitudinal girders and has completely represented thetanks, although only one capture cell was given for each one.

    Save the work.

    2.7.2 Design Criteria Stillwater Bending Moments and ShearForces

    Switch to Section 4.3.1

    Choose the menu point Design Criteriain the POSEIDON ND TreeView and select Hull Girder Bending! Stillwater. Here you may enter stillwater values at selected locations along the ships length. Thevalues will be interpolated linearly. Default values will be provided resulting from GL ConstructionRules.

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    Figure 57: Input mask for stillwater bending moments and shear forces

    As you have not entered any own values so far, you can see the standard values. They are givenrelative to scantling length L. At 0.3*L and 0.7*L the maximum and minimum stillwater bendingmoments and shear forces are calculated, according to the GL rules (part 1, chapter 1, section 5).

    The bending moment and shear force curves will be shown in the preview plot of the input window.

    Close all subordinate windows and save your work. Check your vessel by pressing the button for3D Geometry.

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    2.8 Sizing of a Transverse Section


    Generation, sizing and display of the members of the transverse section.


    The transverse section is described with Functional Elements, plates, stiffeners and holes. The loadsexist. Design criteria / loads have been entered and checked.

    2.8.1 Sizing of all Members at Frame 154 in accordance with theGL Rules

    Switch to Section 3.1.2. Press the dimens button , named: 'Determine Scantlings at the actualframe'. Save the data.

    With the diMens command, it is possible to size all members (longitudinal and transverse) of thecurrent frame in accordance with GL Rules. The diMenscommand automatically carries out all stepsnecessary for sizing.

    POSEIDON performs a sizing in several iteration steps. Beginning with their definition, the membersincrementally approach the dimensions which finally conform to the requirements of the GL Rules. Inthis, all of the sizing criteria from cargo, tank load, inner bottom load, shell load, etc. are internallytaken into consideration. At last, a buckling check will be performed.

    Members with preset dimensions are retained during the process. Presetting the dimensions of plates

    and profiles, for example in the upper flange area, assists the program to fulfill the longitudinalStillwater Bending Moment and Shear Force criteria (see Figure 58).

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    Figure 58: Predefined members in the upper Flange of the vessel.

    The dimensioning calculation is completely documented in the POSEIDON INFOFILE. Possible errormessages or warnings for each calculated plate or stiffener will be reported there.

    Section values like section moduli , moments etc. are written at the end ofthe POSEIDON INFOFILE.

    Have a look at INFOFILE in the bottom area of the main window of POSEIDON ND and compare thevalues.

    Figure 59: Summary of scantling results at frame 146

    Scroll through the INFOFILE to see the reported messages or warnings and errors during the sizing.

    The preview shows a colored plot of the section. If you see any red colored member, then thedimension does not meet the requirements of the GL Rules.

    Figure 60: Colored preview of the dimensioned cross section.

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    Get a detailed overview about the calculated scantlings by pressing the plot button and activate thehook plates dim. or the hook stiffener dim.

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    2.10 Assessment of the results of a Transverse Section

    ProblemInterpretation of the calculated dimensions and the applied load criteria. Sizing of the members so thatthe bending stress requirements of the transverse section are fulfilled.


    The members have been generated and sized.

    2.10.1 Correction of the Transverse Section

    Switch to Section 5.1.

    Choose the Menu Point 'Results!Hull Cross Section! Long. Plates' in the POSEIDON TreeView.An overview about the results of the sized cross section will be shown.

    Figure 63: Results of the cross section at fr. 154 (longitudinal plates).

    Here the applied design criteria and longitudinal stresses (acc. Section 5.B.1 of the GL Rules) aregiven for each part. POSEIDON has automatically supplied the tank and outer shell plates with thecorrect design criteria. The plate thickness is rounded to 0,5 mm in accordance with the GL Rules and

    combined with a + or- symbol (green colored background). The symbol ++ indicates that the required

    dimensions are greatly exceeded (blue colored background); -- indicates substantially too small

    (inadequate) dimensions (red colored background). If + or - is displayed, the sized dimensions lie

    within the tolerances.

    If # - symbols (magenta colored background) are displayed in the column Assessment, POSEIDONhas terminated the sizing of a part of an element or of a plate, because of buckling problem, oftencaused by an improper input.

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    After pressing the button, POSEIDON ND shows the calculated plate dimensions in a plotwindow.

    Figure 64: Calculated results for each plate field.

    If all dimensions are acceptable, press the OK button to copy the calculated scantlings to section 3of POSEIDON ND. This is also necessary for the transverse members.

    With the All lines on/offcommand , you can observe that POSEIDON has subdivided the platesaccording to stiffener spacing. A sizing is effected for every subdivision. It is also possible to click the

    to get the results of the subdivisions for one member (seeFigure 65). The header line shows theworst case of all subdivisions of a plate, which is the used result.

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    Figure 65: Result list for each subdivision.

    A click on the button leads to the sizing only for this part and will show a detailed protocol ofthis process in the INFOFILE (see Figure 66).

    If you want to try some variations of the structure to decrease the actual scantlings, it is possible to

    change the white backgrounded values in the result list and press the button again.

    Change the frame spacing a=855 to a=800 of SHELL Plate D, subdivision 1 for example and press the

    button again. You can see, that this change results in a lower plate thickness of 17,9 mm forthis subdivision. Please restore the original frame spacing a=855 and recalculate the values.

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    Figure 66: Detailed result protocol of the shell plate D, subdivision1.

    After a calculation command , the applied input values of the actual subdivision are now in thememory and it is possible to check them very detailed or to calculate some variations in the GL Rulesprogram.

    2.10.2 Duplicate calculations in the GL Rules program

    Switch to the GL Rules program by using the tab GL-Rules of the TreeView. To check the calculatedscantlings of SHELL Plate D, Part 1, choose Section 6.1 of the GL Rules program 'Shell Plating !bottom plating and flat plate keel'. Check the values and try to understand the input.

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    Switch to the GL Rules program by using the tab GL-Rules of theTreeView. The SHELL Plate D is calculated by the design criteria S

    (bottom pressure), Ti1 (tank pressure of tank1, member in tank) and abuckling check was performed for any subdivision of this plate. Checkthe results in Section 3 (buckling), Section 6 (shell plating) andSection 12 (tank structures).

    In our example; we check the results of the criterion shell plating.Choose Section 6.1 of the GL Rules TreeView.

    All input values agree with the values used for the calculation inPOSEIDON.

    Switch back to POSEIDON and save your work.

    Any variations in the result part of POSEIDON (Section5) or in the GLRULES program take no effect on the accepted / stored results. If you

    want to realize a variation of the structure, it has to be made in Section3 of POSEIDON 'Step by Step by hand'!

    It is possible to create a GL Rules result file by pressing the result-file

    button. The output is shown in the INFOFILE and can beprinted by pressing the printer button beside the result file button.

    Figure 67: GL Rules TreeView

    Figure 68: GL Rules input / result mask (bottom plating).

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    3 Generation of a Further Transverse Section


    Definition of Functional Element SHELL on further frames to realize the hull sha