DATA FORMS

Each object in the model has data items that define its properties. The data are examined and edited in the object's Data Form, which can be accessed by various methods:

 use the Model Browser

 DOUBLE CLICK the object in a 3D view

 RIGHT CLICK the object in a 3D view and use the popup menu.

If a simulation is active then most data items cannot be changed since they affect the calculation, but you can change things like the object's colour.

Control Buttons OK

Accepts the data changes made and then closes the form.

Cancel

Cancels the data changes made and then closes the form.

Next

Accepts the data changes made and then displays the next form in sequence. Holding the SHIFT key down while CLICKING the Next button accepts the changes and then displays the previous data form in sequence. You can also use the keyboard shortcuts F6 for next and SHIFT+F6 for previous.

Popup Menu

The popup menu on a data form provides various facilities, including:

 The data form can be printed, copied to the clipboard or exported to a file. The data for the whole model may be printed using the File | Print menu item.

 Access to the next and previous data form and to the Variable Data form.

 The data names for the currently-selected block of data items.

 Data forms for 3D Buoys, 6D Buoys, Vessels and Lines provide a Connections Report. This is a spreadsheet listing information about other objects connected to it. Note that the same information, but for all objects in the model, can be displayed using the Model | Show Connections Report menu item.

Object properties reports

On data forms of some objects, a report of the properties of that object. It can be opened from the popup menu or alternatively by pressing Alt+Enter. The report displays properties like weight in air, displacement, weight in water etc.

These reports are currently available for General Data, 3D Buoys, 6D Buoys, Vessels, Lines, Line Types, Clump Types and Drag Chain Types.

Calculator

A simple calculator is available from any OrcaFlex data form. It can be opened from the popup menu or alternatively by pressing F12. Numbers can be transferred to and from it with standard Windows copy (CTRL+C) and paste (CTRL+V). The calculator can also be closed by pressing F12 – if you do this then the value in the calculator is transferred to the active edit cell.

3.8.1 Data Fields

Data items on each Data Form are displayed in Fields, generally with related fields organised into Groups or Tables.

You can select a field with the mouse, or use the keyboard to navigate around the form. TAB moves from group to group, and the arrow keys move across the fields in a group.

The following types of fields are used:

Text

A general string of text, used for example for titles and comments.

Name

Each object is given a name, which you can edit. Object names must be unique – you cannot have two objects with the same name.

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Numeric

Numbers can be entered in a number of formats such as 3, 3.0, 0.3, .3 or 3.0e6 or 3.0E6. It is possible to enter more digits than are displayed. The exact value that you enter is used in calculations, even if the program truncates the value for the purpose of display. If the value has been truncated for display, then you can hover the mouse over the value and view the full precision value in the popup hint.

For some numeric data items the values ~ and/or Infinity are permitted. The meaning is data item specific.

Spin Buttons

These are small buttons with up and down arrows, used for incrementing and decrementing the associated field (such as the number of entries in a table).

Check Boxes

These show a tick, meaning selected, or are blank, meaning not selected.

Colour Selection

These show as a block of colour. If you edit a colour field a colour selection dialog is opened.

List Boxes

These allow you to choose from a list of pre-determined values. You are only permitted to use the values that are included in the drop-down list

3.8.2 Data Form Editing

The TAB, SHIFT+TAB, HOME, END and ARROW keys and the mouse can be used to navigate around the Edit Form.

Editing mode is entered by DOUBLE CLICKING a cell with the mouse, pressing F2, or by starting to type alphanumeric characters, which are entered into the field as they are typed. The characters that have been typed can be edited by using the arrow keys to move around (now within the field) and the BACKSPACE and DELETE keys.

Editing mode is ended, and the new value takes effect, when you press ENTER or select another field or button on the form. To end editing mode but reject the edit (and so keep the old value) press ESC.

Many numeric fields have limits on the range of values that can be entered, for example an object's mass must always be greater than zero. Warnings are given if invalid values are typed.

Input can also be from the Windows clipboard. CTRL+C copies the selected field or block of fields to the clipboard whilst CTRL+V pastes from the clipboard into the selected field.

Mouse Actions

CLICK Select Field CLICK+DRAG,

SHIFT+CLICK Select a block of fields

DOUBLE CLICK Start Edit Mode in this field (please also see Data Fields) SECONDARY

BUTTON CLICK Context sensitive popup menu for copying, exporting and printing the form and, for some objects, viewing additional properties

Group Movement

TAB Next Group

SHIFT+TAB Previous Group

ALT+… Move to the group with this letter underlined in its heading Field Movement

← ↑ ↓ → Go to adjacent row or column

HOME Go to leftmost column

END Go to rightmost column

PAGE UP Go to top row PAGE DOWN Go to bottom row Table Editing

INSERT, DELETE Insert or delete rows Start Editing

F2 Edit

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User Interface, Results Mouse Actions

0…9, A…Z Edit (replace) During Editing

← →, HOME, END Move within field End Editing

ESC Cancel edit

↑ ↓ Accept edit and move to previous/next row ENTER Accept edit

Copy / Paste

CTRL+C Copy selected field/block to clipboard CTRL+V Paste from clipboard into selected field CTRL+D Fill selection from top (copy top cell down) CTRL+R Fill selection from left (copy leftmost cell to right) CTRL+U

SHIFT+CTRL+D Fill selection from bottom (copy bottom cell up) CTRL+L

SHIFT+CTRL+R Fill selection from right (copy rightmost cell to left)

3.9 RESULTS

3.9.1 Producing Results

You can access results by either CLICKING on the Results button on the toolbar or by using the Select Results menu item; the Select Results form then appears.

There is a Keep Open switch on the form's popup menu, which allows you to choose whether the form automatically closes when you select a result, or alternatively stays open (and on top) until you explicitly close it.

Graphs and Tables can be sent straight to the printer by CLICKING the Print button. If the values of a graph are required in text form then CLICK the Values button – this give the values in a Spreadsheet window.

The Select Results form allows you to select the results you want by specifying:

Result Type

This option allows you to select which of the various types of results output you require. Results are available as text tables (summary results, full results, offset tables, statistics, linked statistics, extreme value statistics or line clashing reports) or as graphs (time histories, range graphs, XY graphs, offset graphs or spectral response graphs). The types of results available depend on the current model state.

Object

The object for which you want results.

 For the Environment you must specify the global X,Y,Z coordinates of the Position for which you want results.

For sea surface elevation, velocity and acceleration results there is also an option to specify that the results should be affected by the presence of a disturbance vessel.

 For 6D Buoys that have wings attached, results for the buoy and for each wing are available separately.

 For 6D Buoys and Vessels the translational position, velocity and acceleration results are reported at a user specified Position on the object. The coordinates of this Position are specified in object local coordinates.

 For lines you must specify the arc length along the line – see Line Results.

Period

For time histories, XY graphs and range graphs you must specify the period of the simulation to be included. This can be:

 One of the numbered stages of the simulation.

 The Whole Simulation.

 A Specified Period, defined by a start and end time. These time values can be set to '~' which is interpreted as simulation start time and simulation finish time respectively.

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 The Latest Wave (only available for regular wave simulations) which is defined to be the wave period immediately preceding the latest simulation time.

For Range Graphs the period can also be Static State or Instantaneous Value:

 The Static State period is only available after a statics calculation and the graph shows a curve of the values in the static configuration.

 The Instantaneous Value period is available when a simulation has been run. It shows a curve of the values at the instantaneous simulation time. This is normally the latest simulated time. However, if a replay is active then the graph shows a curve of values at the active replay time. This allows you to see, for an entire line, how a results variable evolves over a simulation.

Variable

The desired variable(s).

Definitions of the results variables can be obtained by selecting them in the Variable list box and then pressing F1. Logging for results

The summary and full results are taken directly from the current state of the model. All the other results are derived from the simulation log file which OrcaFlex creates automatically when a simulation is run. As the simulation progresses, OrcaFlex samples the variables for each object at regular intervals and stores the sampled values in the log file. All time histories, statistics and range graphs are derived from the simulation log file.

You can control the time resolution of the results by setting the Target Sample Interval data item on the general data form. This must be done before the simulation is started. Decreasing the sample interval will improve the time resolution of the results (and increase the number of samples taken). However, because more samples are taken this will also increase the size of the simulation file that is created.

Spike Logging

A special algorithm is used for logging results that tend to vary rapidly to ensure that any spikes that may occur between samples are recorded. We refer to this algorithm as spike logging.

Line Results

OrcaFlex spike logs Effective Tension, Torque, Clash Force, Clash Energy, Solid Contact Force, End Force results and Vortex Force results. In addition other results which are derived from these quantities are effectively spike logged by association. Such variables include Wall Tension, Normalised Tension, Direct Tensile Strain, ZZ Strain, Worst ZZ Strain, Direct Tensile Stress, von Mises Stress, Max von Mises Stress and ZZ Stress.

Link and Winch Results

OrcaFlex spike logs Tension and Velocity.

Solid Results

OrcaFlex spike logs contact force magnitude.

General Results

OrcaFlex spike logs Implicit solver iteration count and Implicit solver time step.

Inadequate segmentation warning

If any lines have, during the simulation, gone into greater compression than their segment Euler load then a warning note is added to the Results form. Such lines are marked with the symbol § in the Object list. Usually this means that finer segmentation is needed in some sections of these lines in order to model compression adequately.

Offset warning

If any of the multiple statics calculations have failed then a warning note is added to the Results form.

3.9.2 Selecting Variables

Each object has associated with it a list of currently selected results variables.

For the currently selected object, its selected variables are shown in a list on the results form – you can of course modify this list. For some result types the list can contain multiple selected variables. If multiple variables are selected, then the Values button will give a single Spreadsheet Window with a column for each selected variable, and the Graph button will give a separate Graph Window for each variable.

New columns can be appended to existing time history spreadsheet windows, as follows:

 Select the spreadsheet window to which you want to append, by clicking on it.

 Then open the Select Results form and select the variables that you want to append.

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 Then hold the CTRL button down and click the Values button.

 Provided that the selected spreadsheet window is a time history values table and that the time periods for both sets of histories match, then the new time histories will be appended to the active window. This allows you to have a single window containing results from different objects.

3.9.3 Summary and Full Results

These spreadsheet windows give the current state of an object or of the whole model. For example, in Statics Complete state the full results tables show the positions of objects in their static position. If a simulation is active, then they show the positions of objects at the latest time calculated.

To obtain one of these results tables:

 Select Summary Results or Full Results on the Results form.

 Select the object required.

 Click the Table button.

The summary results are simply an abbreviated form of the full results, in which the results for lines only include the end nodes, not all of the intermediate nodes.

Explicit integration time steps

When the model is in Statics Complete state the summary and full results include estimates of the shortest natural periods of objects or of the whole model. These can be used to determine suitable explicit integration time steps.

The simulation inner time step should normally be no more than 1/10th of the shortest natural period of the model – this is given at the top of the summary results or full results report for All Objects. In addition the full results table for a line contains detailed reports of the shortest natural periods.

3.9.4 Statistics

The Statistics report provides, for each statistics variable:

 The minimum and maximum values and the simulation times when they occurred.

 The mean and standard deviation (i.e. the root mean square about the mean).

These statistics are reported for each of a number of periods of the simulation. If Statistics by Wave Period is selected then these periods are successive wave periods; otherwise they are the stages of the simulation.

To obtain a Statistics report:

 Select Statistics.

 Select the object and the variables of interest (see Selecting Variables).

 CLICK the Table button.

The report is presented in a spreadsheet.

Note: Be careful when interpreting statistics of Line Clearance and Seabed Clearance, since these results are already minima – the shortest distance to any other line and to any point on the seabed. For example, the maximum of Line Contact Clearance will be the maximum value that the smallest clearance took during the period.

3.9.5 Linked Statistics

The Linked Statistics table relates a group of variables for a given object. For a specified group of variables and a specified period of simulation, OrcaFlex finds the minimum and maximum of each variable and reports these extreme values, the times they occurred and the values that all the other variables took at those times.

The report also includes:

μ mean,

σ standard deviation,

Tz mean up-crossing period, estimated as the average time between successive up-crossings of the mean value μ, Tc mean crest period, estimated as the average time between successive local maxima,

m0 zeroth spectral moment, estimated as σ², m2 second spectral moment, estimated as m0/Tz2, m4 fourth spectral moment estimated as m2/Tc2,

ε spectral bandwidth parameter, estimated as (1-Tc2/Tz2)^½,

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To obtain a Linked Statistics report:

 Select Linked Statistics.

 Select the required object and period.

 Select the variables of interest (see Selecting Variables).

 CLICK the OK button.

The report is presented in a spreadsheet.

Note: Be careful when interpreting statistics of Line Clearance and Seabed Clearance, since these results are already minima – the shortest distance to any other line and to any point on the seabed. For example, the maximum of Line Contact Clearance will be the maximum value that the smallest clearance took during the period.

3.9.6 Offset Tables

These Text Windows are available only after multiple statics calculations and only for vessels. For a given offset direction they report the total load on the vessel and show how it varies with offset distance. The worst tension in any segment of any line connected to the vessel is also reported for each offset.

To obtain an Offset Table:

 Select Offset Table on the Results form.

 Select the offset vessel.

 Select the offset direction required.

 CLICK the Table button.

The report is presented in a spreadsheet.

3.9.7 Line Clashing Report

The Line Clashing Report produces a detailed tabular report about the line clashing events during a simulation.

To obtain a Line Clashing Report:

 Select Line Clashing Report on the Results form.

 Select a line.

 Select the period required.

 CLICK the Table button.

The report is presented in a spreadsheet.

Contents of the Line Clashing Report

The report lists a summary table followed by a detailed table as described below.

Summary table

The summary table lists all clash events for segments on the selected line. A clash event is deemed to start when a segment from the selected line first comes into contact with another line segment. We shall refer to the selected line as L1 and to the particular segment on this line as S1. The clash event ends when S1 is no longer in contact with any other line segments.

Note: During the course of a clash event the segment S1 may be in contact with a number of different line segments from other lines, e.g. if the clash is a sliding contact. This is counted as a single clash event from the perspective of S1.

For each clash event the following results are reported:

Event number

A number of clash events may occur during the simulation. Each event is given a number to identify it. This is useful when relating the summary results of a clash event to the detailed results.

Segment number and segment arc length

This identifies the segment S1 on the selected line.

Start Time, End Time and Duration

The simulation time of the start and end of the clash event together with its duration.

Total Impulse

The total impulse of the clash event.

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User Interface, Results Peak Clash Force

A scalar value reporting the greatest value of clash force achieved during the clash event. The clash force vector is monitored during each clash event and the greatest magnitude of this vector is reported.

Peak Clash Energy

A scalar value reporting the greatest value of clash energy achieved during the clash event.

Max Penetration

At each time step we calculate the depth of penetration between the outer surfaces of segment S1 and all other segments. Let S2 be a segment on another line.

Let the radii of the two segments be r1 and r2 (as defined by the line type contact diameter). OrcaFlex calculates the shortest separation distance, d, between the centrelines of the two segments. The penetration of these two segments

Let the radii of the two segments be r1 and r2 (as defined by the line type contact diameter). OrcaFlex calculates the shortest separation distance, d, between the centrelines of the two segments. The penetration of these two segments

In document OrcaFlex Tutorial (Page 65-71)