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SAFER, SMARTER, GREENER

SAFEGUARDING

LIFE,

PROPERTY

AND THE ENVIRONMENT

SESAM RELEASE NOTE

HydroD Wave load & stability analysis of fixed and floating

structures

Valid for program version 5.1-06

Sesam Release Note

HydroD

Date: 06 May 2018

Valid for HydroD version 5.1-06

Prepared by DNV GL – Digital Solutions

E-mail sales: [email protected]

© DNV GL AS. All rights reserved

This publication or parts thereof may not be reproduced or transmitted in any form or by any means, including copying or recording, without the prior written consent of DNV GL AS.

mailto:[email protected]

| Sesam Release Note | HydroD V5.1-06 | www.dnvgl.com/digital Page i

Table of contents

1 DOCUMENTATION ........................................................................................................... 1

2 NEW FEATURES .............................................................................................................. 1

3 BUG FIXES ..................................................................................................................... 2

4 OTHER .......................................................................................................................... 6

| Sesam Release Note | HydroD V5.1-06 | www.dnvgl.com/digital Page 1

1 DOCUMENTATION

HydroD is an interactive application for computation of hydrostatics and stability, wave loads and motion

response for ships and offshore structures. The wave loads and motions are computed by Wadam or

Wasim in the Sesam suite of programs.

HydroD V5 is a completely new version of HydroD, instead of an upgrade of V4. It is developed on a new

IT platform in accordance with DNV GL – Digital Solutions technology roadmap and has the capacity of

hydrostatic and stability computation. The wave loads and motions computation will be supported in the

coming versions.

In HydroD V5.1 many new features have been added compared to version 5.0, and a large number of

defects have been fixed. With a few exceptions, version 5.1 is compatible with the database and js-file

created by version 5.0. The exceptions are given in section 4.

2 NEW FEATURES

• Improvements and new features in the heeling force model:

o User defined height coefficients. Option for manual specification of height coefficients in a

heeling force model of type ShapeCoefficientWindHeelingMoments.

o Checkbox for each set in the shape coefficient table. A set may be specified as not active,

meaning the default shape coefficients are used.

o User defined wind heeling forces. In addition to specifying the wind heeling moments,

the user now has the option to specify the wind heeling forces. This also includes

specification of the heeling force centre.

o Property dialog for user defined wind heeling moments has been reorganized. In

previous version, the property dialog has separate tabs for table specifications of

azimuths, waterline Zs and heel angles. Now this has been included in one common tab

“Heeling moments”.

o Combining several element models into one heeling force model. A new concept

CompositeElementModel to assemble element models including transformations into one

model is available. By using this option, the users may easily change positions of e.g. a

cargo being part of a wind heeling force model. The attached example TutorialStability1

has been modified to include this feature.

o The shape coefficient option has a new method (Surface integration) for calculation of

wind heeling moments. The new method, which may be applied when the outer surface

is closed, is more accurate and faster than the old method (Grid resolution).

o The requirement to have an element model specified for a heeling force model has been

removed when the heeling force model is of type UserDefinedWindHeelingMoment. The

reason for this is that the element model is not needed for the calculation in this case.

• Activities for running analyses in parallel or sequence: In the Analyses folder, the user may now

create separate activities for running the analyses in parallel or sequence.

• Import clean js-files from HydroD version 4.10 or later: The version 4 js-file will be recognized

from the text string in the first line starting with the text “//Exported using: HydroD V4.X-YY”,

where X must be 10 or larger. Before creating the HydroD 4 clean js-file, the input unit should be


set equal to the database unit. A summary of the translation is written to the output window. For

a complete list of unsupported features and features with limitations, see UM sec. 4.1.1.2.

• Improved performance when changing properties in a big workspace: In the previous version

changing a property had bad performance when the workspace was big. A clean up of the code

to improve the performance has been done.

• Reports from individual sections: A new option “Generate report from section” is now available in

the Report->Section context menu.

▪ Improvements of the mass model:

o Option to specify the mass model as a mass matrix

o Translation of mass model made available for all types. In previous version translation

was only available for a mass model of type “From element model”.

o Specification of inertia coefficients included in mass model of type “User specified”. Note

that version 5.1 is for hydrostatic and stability computations. The inertia specifications

will therefore not have any impact on the analyses in this version.

▪ Multi select of compartments in sounding table: In the “Results” tab of a compartment model,

the user may now select an arbitrary number of compartments. In previous version, only one or

all compartments can be selected.

▪ Sub-folders of same type as main folder: In the folders Analyses, Plots, Tables and Pictures, a

subfolder of the same type may now be created.

▪ Display of floating position: After a stability analysis is completed, the user may display the

floating position. This is controlled by the style tab of the stability analysis.

▪ Stability criteria reference document: A separate document including references to stability

criteria used in rule checks is available from the help menu.

▪ Beach lines: A new feature “BeachLine” defining the intersection between a horizontal plane and

a limit surface is now available for the limit surface analyses concept.

▪ Cross section Postresp name: The results table of a strength analysis has a new column showing

the name of the section in a Postresp analysis.

▪ Improvements/changes when editing a property grid:

Button Version 5.0 Version 5.1

Down arrow when a cell in last row is active

- New row

Left/right/up/down arrow Submit value and jump to next cell

As 5.0

Enter Submit value and jump to

next cell

Submit value, remain in

current cell

Keyboard-Delete - Clear cell value

LMB/RMB in column header No sorting Sort ascending/descending

“+” sign in property grid to add a new row

The current active cell remains active

First cell of the new row becomes the active cell

3 BUG FIXES

• Inconsistency in journaled script commands when doing copy, undo, paste. (OTD9955)


Note that when fixing this bug, a change in the copy/paste feature between version 5.0 and 5.1

has been done. This is described in section 4.

• Calculating equilibrium condition is logging LoadingCondition.BalanceAsync() to script file and not

LoadingCondition.Balance(). (OTD9689)

Program has been corrected to journal LoadingCondition.Balance().

• Lis file name of MaximumKgAnalysis isn't changed to user specified name. (OTD9826)

• Redo generate line series logs redundant js-commands. (OTD10225)

• Buttons for turntable rotation and spin do not work. (OTD11137)

The buttons did not work properly and have been removed from the ribbon bar.

• CVS culture setting in Options dialog do not change to its default value when doing reset.

(OTD11383)

• Can’t undo a single compartment specified as damaged by one click. (OTD11854)

• Copying the position of an opening to Excel includes the unit. (OTD12000)

• Unit specified in table isn't used when generating Excel report from workspace. (OTD12001)

• Centre of gravity values duplicated in mass model results view. (OTD12132).

The values LCG, TCG and KG has been removed from the results view as they are covered by the

values for X, Y and VCG respectively.

• The block coefficient is not calculated correctly. (OTD12496)

Note that when fixing this bug, a change in calculation of the moulded draft between version 5.0

and 5.1 has been done. This is described in section 4.

• Button “Zoom extents” doesn’t work correctly when element model unit is changed from m to

mm. (OTD12514)

The defect has been fixed when the FEM model is a first level superelement. The bug still exists

when the FEM model is a higher level superelement.

• Mass and COG aren't correct if mass unit of an element model with point mass is changed.

(OTD12517)

• Info on version number is missing in js-file from File->Save as script. (OTD12540)

• Xml files are not renamed when renaming the analysis. (OTD12611)

• Export plot to *.svg and *.pdf files do not work. (OTD12619, OTD12620)

Option to export to svg and pdf have been removed from program.

• HydroD can’t read a top level superelement model where translation has been used in Presel.

(OTD12622)

• Time out for adjust filling doesn’t work. (OTD12700, OTD15133)

Some enhancement of the code has been done to break the calculation more efficiently when

timeout has been reached. The lightbulb has been updated with a more detailed description of

the filling operation.


• Shape coefficient wind heeling method with high resolution specified cause NaN in results view of

a maximum KG analysis. (OTD12733)

• Option “Shrink” not disabled when “Show plates” is unchecked for an element model. (OTD12750)

• Exception when exporting to template if the report includes a plot of maximum KG analysis.

(OTD12804).

• FEM files including FTAS shell elements can’t be read by HydroD. (OTD12816)

• Results view of mass model and lis file are not updated when loading condition is changed.

(OTD12882)

• Adding a fluid by running the script command in commands window creates error. (OTD13037)

• Ixy/Ixz/Iyz written to lis-file not correct for a mass model of type point mass table. (OTD13122,

OTD13128)

• Second order beam elements in a Morison model are not shown correctly (OTD13525)

• Height coefficient table only shows the third column after loading an old workspace. (OTD13767)

• Wind arrows are not displayed correctly. (OTD13875)

• Reference text in a stability rule is not updated when changing from predefined to custom.

(OTD13939)

• COG for a user specified mass model is shown in wrong position when Global is specified as

coordinate system. (OTD13972)

• FEM files containing GELREF1 card with GEONO/OPT=-1 can’t be read by HydroD. (OTD14099)

• Width of columns too small in tables showing compartment model and compartment contents

(OTD14243)

The program has been updated to adjust width of the columns to the table contents.

• The "Fixed angle from initial condition with vertical offset" surface constraint is not correct if the

initial condition of the associated StabilityAnalysis is not upright. (OTD14247)

• Size and extrema for second order beam elements are not correct in the result view of an

element model. (OTD14512)

• SaveWorkspace() command in js input file do not save script file properly. (OTD14559)

• Wind heeling moment is not calculated correctly in the projected area method for a translated

heeling force model with symmetry transformations. (OTD14687)

• Stability rule check cause error in journaled file when the workspace is from a "Save as script"

js-file. (OTD14813)

• Computed center of flotation for a superelement model with transformed superelements is not

correct. (OTD14905)

• Exception thrown when importing Wasim mass file to mass model. (OTD15023)

• PlateThicknessCorrection=true cause error in center of buoyancy when panels don't have

thickness. (OTD15168)


• Global origin in 3D view isn't updated when changing coordinate system size/diameter of loading

condition. (OTD15172)

• No error message when stability analysis fails due to insufficient memory. (OTD15185)

• Dummy hydro pressure missing for a single superlement model with 4 node triangular elements

created by Wadam. (OTD15243)

• Panel labels displayed incorrectly. (OTD15274)

• Changing length unit in element model causes error message in mass and compartment model.

(OTD15278)

• Changing permeability and stability criteria parameters does not always trigger the “out of date”

warning symbol to be shown for a maximum KG analysis. (OTD15297)

• Button "Select complement" only works when concepts have been selected by "Select all".

(OTD15339)

• Unit is missing when writing "Infinity" to a js-file. (OTE15344)

• LimitSurface concept shows wrong name for stability analysis in input field. (OTD15400)

• Reference command disappears when reading a saved js-file including copy/paste. (OTD15403)

• Can’t undo change of permeability to its default value. (OTD15473)

• Compartments, CompartmentContents and DamgedCase settings are not restored if user undo a

change of the element model. (OTD12533,OTD15534,OTD15660)

• The upright position in GZ curve is not correct when the initial condition is "Loading condition".

(OTD15637)

• Copy/paste of stability analysis and stability rule check cause error when reading the journaled

script file if the copied rule check refers to the copied stability analysis. (OTD15642)

• Results view of projected area wind heeling moments do not show correct CLR Z. (OTD15719)

• Failure in user defined wind heeling moment results view when unselected types have equal

values assigned. (OTD15746)

• Undo operations may cause the Reference command to disappear from the journaled js-file.

(OTD15809,OTD15813,OTD15814,OTD15816,OTD15817)

• Shape coefficients of sets are cleared when creating a workspace with a journaled script file.

(OTD15771,OTD15900)

• Error in journaled rename command when rename is followed by undo and then redo.

(OTD15815)

• An element can get the shape coefficient of a set which doesn’t contain the element.

(OTD15849,OTD15850)

• Wind heeling moment calculation by the shape coefficient method will fail if more than one

superelement define sets. (OTD15851,OTD15852)

• Shape coefficient wind heeling moment results are wrong when beams on the FEM-file have the

diameter specified to zero. (OTD15858)


• Heeling force model is displayed in wrong position w.r.t. SWL. (OTD15830, OTD15854)

• Computed wind heeling moment for a superelement model with transformed superelements is

wrong. (OTD15878)

• Specified air density has no effect on calculated wind heeling moment. (OTD15901)

Note the issue w.r.t. incompatibility between version 5.0 and 5.1 described the table in section 4.

• Wrong description of stability criteria parameters when they are reused in different criteria.

(OTD15921)

• Results of waterplane and initial static stability are not correct when there is free surface in

damaged compartments. (OTD16233, OTD16265)

• Compartment model FEM file must be in SI units when read from a js-file. (OTD16261)

• Reference to objects not stored properly in database file. (OTD16277)

Note that the bug has been fixed in version 5.1 by storing the references in the database (hydx)

according to the status when the workspace is saved. This means that when opening a database

created by version 5.0 in version 5.1, the behaviour will be as described in HydroD Status List.

• Second moment of area of pipes in a Morison model is not calculated correctly. (OTD16286)

• Wrong version number shown in js-command documentation. “Help->JS command document”.

(OTD16367)

• HydroD may fail to find the balanced floating position of a loading condition when openings are

submerged. (OTD16408)

4 OTHER

• A known new defect has been introduced in the compartment model: From version 5.0 to 5.1, a

number of defects regarding the compartment model has been fixed. This has required a lot of

changes in the source code which again has introduced a defect that has not been solved before

release of 5.1. The bug is that if a CompartmentContents, which belongs to a LoadingCondition,

is shown ABOVE the CompartmentModel in the browser, then a clean js-file created from the

workspace will not restore the compartment contents settings. To avoid a workspace which may

cause this problem, the loading condition should be created after the compartment model, or if

not, the order of the objects shown in the browser must be changed so that the compartment

model is above the loading condition. Note that the bug is also present when reading a clean js-

file created from a workspace in version 5.0. (OTD16379)

• Incompatibility in database and js-file HydroD version 5.0 to 5.1

Feature Importing a 5.0

database (hydx)

into 5.1

Importing a 5.0

clean js-file (Save

as script) into 5.1

Importing a 5.0

journaled js-file

(Save) into 5.1


User specified mass

model: Mass is

negative.

Inertia coordinate

system = Input in

5.1. This gives an

error, and user must

manually change to

COG centered.

Inertia coordinate

system = COG

centered in 5.1

Inertia coordinate

system = COG

centered in 5.1

User specified mass

model: Mass is

positive.

Inertia coordinate

system = Input in

5.1. No impact on

hydrostatic and

stability analysis

results. No need to

change to COG

centered.

Inertia coordinate

system = Input in

5.1. No impact on

hydrostatic and

stability analysis

results. No need to

change to COG

centered.

Inertia coordinate

system = COG

centered in 5.1.

Air density is specified

different from the

default value 1.222

kg/m^3

If the value of the air density has been changed by the user in version

5.0, then when reading the file into 5.1, the wind heeling moment

calculated will be different from the wind heeling moment calculated in

version 5.0. In 5.0 the default value is always used.

• By the new option to specify inertia coefficients in a user specified mass model, a known defect

and a limitation has been introduced when the mass is negative. A negative user specified mass

is regarded as a point mass, thus the inertia coordinate system must be “COG centered”. If not,

an error message is given in the property dialog.

o Limitation: To escape from this setting, the users may either 1) change the mass to a

positive value, or 2) switch to “COG centered” directly. If option 2) is selected, then it

will not be possible to undo this.

o Known defect: If a clean js-file is created from this setting and read into a new

workspace, then the inertia coordinate system will automatically become “COG centered”.

The parameters for radii of gyration and product of inertia is however NOT changed,

meaning the mass model itself has changed. This defect is harmless for stability and

hydrostatic analyses in version 5.1 since inertia coefficients is not used in this case.

• The option for validation of an element model has been removed from the program. This feature

was mainly a debugging tool and has not been thoroughly tested. Users should check and verify

the model inside GeniE.

• The option for markers was not properly included in the program, and has therefor been

removed from the HydroViewSetting concept. (OTE13374)

• Code check may fail because of a small negative righting moment at 0 degrees (equilibrium).

User manual section 4.6.3.5.2 has been updated with information about this. Can be handled by

using the tolerance of the loading condition. (OTD15411)

• Calculation of the moulded draft has been changed (OTD12496):

o In HydroD 5.0, the moulded draft is calculated using 3 cutting planes parallel to the YZ

plane in the global coordinate system. The cutting planes are distributed evenly along

the X axis of the global coordinate system between the minimum and the maximum X


coordinates of the submerged buoyancy body. For each of the cutting planes, the

minimum Z coordinate of the submerged body in the global coordinate system is taken

as the moulded draft. If a cutting plane don’t cut any submerged body, the moulded

draft is set to zero. The average of the moulded drafts for the 3 cutting planes is taken

as the mean moulded draft for the vessel.

o In HydroD 5.1, the moulded draft is calculated from 3 transverse sections distributed

evenly along the X axis of the input coordinate system between AP and FP. The

transverse section in the middle is the midsection. For each transverse section, the point

with the minimum Z coordinate in the global coordinate system is taken as the reference

point. The distance from the reference point to the intersecting line of the transverse

section and the waterplane is calculated as the moulded draft. The average the moulded

drafts for the three transverse sections is taken as the mean moulded draft for the vessel.

• The copy/paste feature has been modified. This is due to an inconsistency in the journaled script

commands in 5.0 when undo is used in combination with copy/paste (OTD9955).

As an example, assume Location1 is existing in Environment folder and copy/paste is used to

create a copy of Location1. In version 5.0, separate commands are journaled for both the copy

and paste operation. If the user performs undo after copy, then the journaled copy command is

removed while clipboard is not cleared. A subsequent paste operation will create a copy of

Location1 named Location1_1 in Environment folder which can’t be recreated by reading the

journaled js-file for the workspace session.

In version 5.1 copy/paste is journaled used one single script command when “Paste” is

performed, i.e. no script command is created after “Copy”. Selecting “Copy” in Location1 context

menu and then “Paste” in Environment context menu will generate the script command

“Copy(Location1, Environment);” and Location1_1 is created. The users should note the

following behaviour of the copy/paste feature:

o Copy Location1, paste => a copy of Location1 is created

o Copy Location1, delete Location1, paste => a copy of Location1 is created

o Copy Location1, modify Location1, paste => a copy of the modified Location1 is created

o Copy Location1, modify Location1, delete Location1, paste => a copy of the unmodified

Location1 is created

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