Reduce your costs and increase quality with GeniE and HydroD by creating one concept model only for hydrostatic, hydrodynamic and structural analysis.
DNV Software continues its strategy to enhance Sesam according to the needs of the industry. Since the March release of Sesam, significant investments have been put into developing new functionalities in GeniE and HydroD, such as capacity checking, more robust modelling and easier hydrodynamic analysis. During the fall of 2007, new versions of the industry-leading software tools GeniE and HydroD will be released in line with the vision that Sesam shall be the No.1 efficient engineering tool of offshore structures.
GeniE – engineering for the future
An intuitive implementation of the most recent code checks makes engineers more productive. At the same time, complex structures can be made in shorter time using advanced meshing algorithms.
Code checking for members and tubular joints
The new version of GeniE supports the latest code checking standards for members and tubular joints according to API-WSD and Norsok, including AISC-ASD and Eurocode respectively, for non-tubular profiles. It is also possible to use AISC-ASD and Eurocode for onshore applications. We are currently implementing the latest API-LRFD and ISO (draft revision) code of practices, and expect these to be part of a release scheduled for end Q2/2008. There are several reasons for using the code checking in GeniE. The most important ones are up-to-date code checks, much more intuitive, automatic detection of worst code checking positions and better means of reporting the results. It is also possible to compute beam stresses and present these in a 2D view; this can also be done for forces and moments. The graphs may present results for single loadcase(s), or you oan show envelopes based on a selection of loadcases. All details may be exported to Microsoft Excel (via XML) for further processing.
Advancing Front Mesher
We are pleased to announce the implementation of an Advancing Front Mesher in GeniE. Such meshing techniques are also referred to as paver meshing. The existing Sesam Quad Mesher is ideal to use for slender and regular structures such as the hull or the topside of a semisubmersible or FPSO. The Advancing Front Mesher has been implemented to facilitate the generation of quality mesh close to complex geometries with a minimum of user interaction. Typical examples are around holes and penetrations in a plate or as shown above, for a tubular joint with several overlapping braces. The illustration above shows the results on a mesh with no user interaction except the specification of a characteristic mesh size. With more robust modelling features and improved ways to generate and control the finite element mesh, it now takes less time to make complicated structures and analyse them to derive the desired results.
Improved data transfer
There is also a continuous effort in improving the data transfer from CAD systems to a CAE system like GeniE. Previous issues of DNV Software News have explained the features for data transfer using formats like SAT (as in Intelliship), sdnf (as in PDMS and PDS) and scad (as in Nauticus Hull Section Scantlings). We have now made a utility tool for converting the lines you find in a DXF file and import these as guiding lines in GeniE. In the example above, the guidelines (poly-curves) were imported into GeniE and used as references when creating the hull by using skinning or covering techniques. The FE mesh was made without any user interaction. It is also possible to automatically make beams (but without properties) from 2D DXF – a typical example is on a topside deck structure. GeniE is thus now more robust to import data from other systems, and the engineer will be more effective as more data can be re-used.
HydroD - wave loads and motion responses
The March 2007 release of HydroD was a significant upgrade of the hydrostatic and stability capabilities within the program. Furthermore, the integration between HydroD and GeniE (to create panel, mass and structure models) is significantly improved. Based on market feedback, we have continued to enhance HydroD. It is now a complete solution for sea-keeping analysis and documenting safety at sea. By using the latest version we also expect our users to realise that such analyses are now faster, easier and more productive.
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| Compartments automatically created by GeniE, and typical filling of some of the tanks. | Hydrodynamics pressures are acting on the panel model - here shown in Xtract started from HydroD. |
Compute allowable vertical centre of gravity (AVCG) for intact and damaged conditions. Such computations present graphs with the AVCG and tables with critical axis.
The new HydroD version accounts for the thruster forces when computing the heeling moment. You can now make your own code checks where you specify the thresholds for acceptance or not. Such code check comes in addition to the existing code of practices from e.g. Marpol, IBC, IGC, IMO Modu and NMD.
The equilibrium calculations have so far either been performed by using the compartment fillings defined by the engineer or automatic filling of compartments to achieve a desired floating position. In the new version of HydroD, the latter option is now performed with the objective of minimising the GM. Furthermore, the hydrostatic balancing (trim, heel, draft) has been improved so that it always finds a stable equilibrium position.
The new version significantly speeds up the process of creating a range of loading conditions based on a template condition as well as generating many hydrostatic analyses. It is also possible to stop the stability analysis at typically first flood or second intercept. To perform stability analysis, it is often required to have many loading conditions (typically with intact or damaged conditions).
To better understand the physics, it is possible to look at the stability animations. This capability has now been supplemented with a display of the animation angle on the GZ-curve graph. In other words, the engineer can look at the stability animation and at the same time get information on the corresponding GZ value.
Information from the various hydrostatic and stability analyses can be retrieved in several ways; from graphics, from the browser or from making a report. The new version of HydroD includes more information on the report; hence the ability to document and to verify has been improved.
More flexibility in how to use information given in various units for the same project. It is now possible to convert the units which are part of the neutral files (also known as FEM files) from the modelling tools (typically GeniE).
When HydroD was introduced some years ago, the main objective was to serve as an interactive tool to set up and run analyses in the frequency domain (Wadam). Since then, we have added capabilities for hydrostatic and stability computations. The new version of HydroD makes it possible to set up and execute linear and non-linear analysis in the time domain (Wasim). This allows the same concept model (as defined in e.g. GeniE) to be used for all the mentioned hydro analysis. As such, significant time in modelling can be saved, and all relevant analyses can be performed by the same tool.
Definition of setup parameters are included and additional modelling features required to run Wasim. Examples are easy definition of section models, cutting of panel model by extracting panel model gridlines and pre-generated geometries such as circles, cylinders, cones etc.
Wasim was developed for vessels with forward speed. However, the offshore industry has realised the importance of analysis in time domain (with and without non-linear effects); it is now possible to include the effect of moorings and risers as well as to run with zero forward speed.
To speed up the analysis, it is now possible to run it using multi-thread options and/or on multiple machines.