|
|
| The FlagShip stability module is based on the GHS
program, a worldwide standard. GHS is a comprehensive, full-featured program
addressing virtually every aspect of form, flotation, stability, and longitudinal strength
applying to surface and submarine vehicles of all types. GHS uses true
center-of-gravity shifts of tank contents both transversely and longitudinally, allows
heeling about any axis, and automatically handles the IMO "Severe Wind and
Rolling" and "Probabilistic Damage" criteria. A powerful macro language
allows complex stability analyses to be easily automated, and it has unsurpassed
capabilities in modeling complex structures with detailed compartmentation.
GHS is designed to be used during all stages of design, beginning with early studies of hydrostatics, tank volumes, and stability, continuing on to trim and stability booklets, and even on-board stability systems. Its ability to define the compartmentation model as associative to the hull offsets, and to define a complex series of conditions and analyses, makes it easy to re-run detailed calculations as the hull shape is refined during the design process. In addition to the basic hydrostatics and curves of form calculations, GHS can be used to carry out complex and detailed analysis of just about any condition. Some of the features of these analyses include:
GHS contains an offset editor for entering hull offset data, or it can read data from FastShip, DXF, or SHCP files. Once the hull offsets are in the system, the GHS Partmaker module is used to model the compartmentation. Partmaker gives the designer a compact set of commands with which to define the boundaries of tanks and compartments, which may be referenced to the hull where appropriate.
Partmaker allows the designer to create "run files", which contain the commands to build the complete compartmentation model. This run-file references the hull, so that if the hull is modified later, the compartmentation model may be re-built almost instantaneously.
Once the model is complete, analysis may begin. Flotation conditions may be defined by drafts, trim and heel angles, displacements, and centers of gravity. Hog and sag of the hull may be accounted for as well. Loading is specified by overall weight and center of gravity, or any number of point or distributed weights, and tank loadings specified by volume, weight, percentage full, ullage, or sounding. Stability criteria are easily defined, and some standard criteria are built in. The stability criteria may be defined in many ways, such as a lower limit on the angle of maximum righting arm. GHS, through a set of menus, can carry out standard hydrostatics and stability analyses. However, the real power of GHS lies in its run-file and macro facilities. These allow the naval architect to design an entire set of calculations to be performed, perhaps finding the maximum VCG in a number of loading conditions, each with a number of damage scenarios with intermediate stages of flooding. Once this run-file is set up, the entire analysis can be run at the push of a button, including the creation of output data files, and tabular and graphical output to the printer.
What if the hullform changes after the analysis is completed? Just re-run the Partmaker run-file to create the new geometrical model, and then re-run the analysis run-file. This approach can save many manhours, and more importantly, help to avoid costly and difficult to discover errors. In constant use by major design firms and shipyards, GHS is well proven, reliable, and well accepted by regulatory agencies. GHS is truly general-purpose. Not only does it handle ship hulls, but also anything that floats or contains liquid - or both. It has been used to analyze submarines, SWATHs, dry docks, drilling platforms, 10-foot sailboats, 300-meter freighters, floating bridges, and even a floating golf course. GHS is unique in its combination of a simulation-oriented approach to analysis, and its complete scripting capability. These give the designer a very powerful tool that can easily be applied at any stage of design, with complete confidence and significant time-savings. |
|||||
Copyright © 1999 Proteus Engineering. All
rights reserved. |
