MOSES, a new language for modeling, simulating, and analyzing the stresses which arise in marine situations. This new language offers the necessary flexibility along with the rigor of a programming language. Now, one can easily create new models, document them, and assess their validity - all with a single program.

With the generality necessary to convey the comprehensive nature of MOSES, it is often unclear precisely what type of problem that MOSES can handle. Below, a brief list of tasks that have been successfully tackled is given. This list, of course, is not complete since MOSES is extraordinarily adaptable.

• Traditional hydrostatics
• Ballasting during loadout
• Stress analysis during loadout
• Multi-Point mooring design and analysis
• Tanker berthing analysis
• CALM and SALM analysis
• Simulation and stress analysis of lifting structure off of a barge and lowering it into the sea.
• Pipelaying from a stinger
• Pipelaying from davits
• Simulation and stress analysis of a jacket off of several barges including the flexibility of the barge in the stress analysis
• Upending of a jacket and performing a stress analysis during the upending
• Simulation of impact during mating operations
• Mating of a deck with a TLP hull
• In service stress analysis of a TLP
• Transporation of a TLP
• Transportation stress analysis of structures including the effect of the barge flexibility.
• Installation of a compliant tower
• Dynamic analysis of a tower being flooded

Alternatively, for those who like details, we have an anotated list of capabilities as follows:

Included in MOSES Minimal

• General Capabilities
• Hydrostatics
• Equilibrium
• Frequency Domain

Optional Components

• Connector Elements
• Pipe and Rod Element
• Jacket Upending
• Time Domain Simulation
• Jacket Launch
• Structural Solver
• Generalized Degrees of Freedom

General Capabilities

• Powerful Command Language enables the user to create macros and take advantage of the modeling capabilities. MOSES is a complete offshore engineer's toolbox. It offers the flexibility to create new models, document them, and assess their validity -- all with a single program. Looping Options - Blocks of data can be entered automatically, rather than manually. Conditional Execution - Routines that execute only when data changes. Variable Definitions - Specific data can be defined as a variable which can then be plugged into other models or used in later operations. Macro Capability - User-defined macros mean commands don't have to be repeated.
• Model Generation of a structure is treated as one or more hulls and a set of tubular and/or plate elements which are assembled into a single body. Generation options and interactive graphics allow easy modeling of unusual shapes, semisubmersibles and tension leg platforms.
• An Extensive Vessel Library is supplied.
• Automatic Mesh Generation of hydrostatic, hydrodynamic and plate meshes. The program refines a coarse mesh and calculates the intersection, union and difference of defined polygons used for mesh generation.
• Versatile Graphics Capabilities enable the user to interactively generate X-Y graphs of results and 3D views of models.
• Post Processing of results is easy and can be customized by the user via macros, or in batch or interactive modes.
• SI, English or Metric units can be used, seamlessly switching from one system to another.
• Vortex Shedding in wind or water is computed.
• Automatic Ballasting computes the ballast necessary to maintain equilibrium, given vessel configuration (draft, trim and heel) and loads. Tanks can also be ballasted interactively, automatically correcting system weight and inertia.
• Minimum Ballast Movement required to achieve a new vessel configuration is calculated.
• Jacket Loadout Calculations are made using the above computations.

Connector Elements

• Catenary Mooring Lines can have up to 30 segments separated by buoys or clump weights.
• Nonlinear Springs can act in tension or compression only.
• Force Elongation Behavior can be specified for spring or mooring lines.
• Gaps, Pins and Lines provide constraints to motion.
• Multiple Sling Assemblies can be used to hold or lift bodies.
• Connector Design Menu expedites design of piles, mudmats, mooring lines and lift slings.
• Spectral Fatigue in connectors can be accumulated.
• Cycles of Tension in connectors can be counted.
• Reposition Menu allows easy adjustment of connectors to change position or achieve equilibrium.

Pipe and Rod Elements

• Large Deflection beam capability.
• TLP Tendon, Rigid Risers and Pipeline Installation can be analyzed using this element.
• Mooring Line Dynamics are included with this element.

Hydrostatics

• Curves of Form can be generated for a set of drafts and trim angles and include displacement, waterplane area, locations of buoyancy center and center of flotation, transverse and longitudinal KM, load to change draft and moment to change trim.
• Intact and Damage Stability with righting arm curves can be generated for a range of drafts and trim angles. Results include righting arm, wind heel arm, area ratio and minimum height of down-flooding points.
• Single Body Equilibrium is easily found. MOSES computes an equilibrium position given the load and ballast of the vessel.
• Longitudinal Strength showing bending moments and deflections of a loaded, ballasted vessel are computed.

Equilibrium

• Multibody Equilibrium automatically includes wind, wave and current forces.
• Bodies can be lifted, lowered or upended with multiple slings.
• Connectors can be activated or deactivated to simulate breaking or rerigging.
• Anchors can be automatically moved to achieve a specified tension.
• Connector Lengths can be changed to achieve a specified tension.
• Multiple Bodies can be repositioned with lines automatically adjusted to equilibrium.
• Interactive Status of the configuration, applied forces and connector forces.

Jacket Upending

• Upending or lifting of a structure can be simulated via a user defined installation sequence.
• Lifting and/or Flooding can be simulated for upending the structure.
• Hook can be held at a constant elevation or load while flooding or pumping.
• Slings can be used for lifting purposes.
• Environment can include current and wind.
• Database capability allows restart at any event within an installation sequence.

Frequency Domain

• Frequency Domain Analysis can be used for structure response to a set of waves of given period and direction. Reports include structure added mass and damping, pressures on the hulls and resultant total forces and moments.
• Morison's Equation can be used for a combination of plates and tubes with hulls to form a structure, or simulate a semisubmersible or self-floater.
• Strip Theory is fast and efficient for traditional hull shapes.
• 3D Diffraction Theory captures bottom effects and hull interaction.
• Response Amplitude Operators (RAO's) are calculated for motions of any point on the structure and for inertial forces on bodies attached to the structure.
• Statistics can be generated, using RAO's, and a variety of spectra; ISSC, JONSWAP, or user-defined. Results are the RMS, significant, average of 1/10 and 1/100 highest response, or maximum responses, based on statistical multiplier or storm duration.
• Nonlinear Slowly Varying Wave Drift Forces can be included in the frequency domain.

Time Domain Simulation

• Simulation determines the time-history response of the system.
• Ocean Conditions can consist of current, irregular waves, wind or any combination of these.
• Frequency Domain Results are transformed into the time domain.
• Multiple Body Motions can be analyzed. A typical example is a tanker attached to a mooring buoy.
• Restart Capability allows continuation of analysis.
• Post Processing of results is easy and can be customized by the user.
• Statistics of results can be computed.
• Tanks can be dynamically flooded based on value properties and actual, differential head
• Tanks can be emptied by defining an air compressor

Jacket Launch

• Dynamic Simulation in time domain treats all bodies with 6 degrees of freedom.
• Parametric Studies are easily performed, simplifying the task of finding the optimum draft and trim condition
• Automatic Ballasting determines desired draft and trim prior to launch.
• Side Launch of a structure can be analyzed.
• Launch from several barges can be investigated.

Structural Solver

• Frequency Domain Stress Analysis allows member and joint checks to be considered spectrally.
• Nonlinear Structural Solution accounts for all nonlinearities.
• Environmental Loads are computed automatically with no need for wind and wave loads files.
• API and AISC code checks are provided.
• Automatic Resize of members with the optional database update.
• Spectral Fatigue can be considered for beams, plates and joints. SCF's are computed for tubular joints using Kwang & Smedley, API, Marshall or Efthymiou, or the user can supply them.
• Eigenvalues and Eigenvectors can be extracted by a subspace iteration technique.
• Joint Crushing can be evaluated.
• Deflected Shape and Modes can be plotted.

Generalized Degrees of Freedom

• Eigenvectors can be used as generalized degrees of freedom in all MOSES analyses
• Generalized Degrees of Freedom can be used to:
• Consider the effect of structural dynamics on the integrity of the structure
• Quickly include the effect of flexibility in loadout analyses
• Include the effect of deformation on the amount of buoyancy
• Consider hydrodynamic interaction between two vessels
• Consider the effect of deformation on frequency response

MOSES Introduction

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