Introduction

The Gulf Coast Region Maritime Technology Center is under contract with McDermott Shipbuilding, Inc. to produce a three-dimensional (3-D) virtual prototype using existing computer-aided design (CAD) data simulations of a floating military structure named the Mobile Offshore Base (MOB).

Background

McDermott's proposed floating military base would be 152 meters wide, 1,500 meters long and 76 meters tall. It would include a runway long enough to land fully-loaded C-130 and C-17 cargo planes. The structure also would contain interior spaces for troop quarters and storage of military vehicles, equipment and weaponry. The MOB will have the ability to transfer cargo from many types of vessels, including RO-RO ships and LCAC type vessels.

Visual simulation evolves from rendering animated, 3-D CAD models of the MOB in a virtual ocean to creating physics-driven virtual tests. The visual simulation of the MOB consists of importing CAD data of the model into the virtual ocean environment, adding auxiliary vehicles and equipment into the model, and utilizing motion data derived from external programs to create physics-based virtual simulations of how the MOB would react under various sea states. The simulations also include the loading and unloading of cargo during various sea states and headings.

The benefits of visual simulation include:

Reduced costs of manufacturing because of early determination of design flaws

Increased ability to provide a quality product due to the team approach to design; this can be done remotely or within the same organization

Reduced design time and costs; designs and associated changes can be considered in a relatively short amount of time

Reduced risks through simulation and analysis of space and ergonomic requirements during the design phase to ensure accessibility/optimization of work areas

Mechanical and operational simulations can be performed and visualized to aidin the determination of

design feasibility

Complex structures can be visualized that aids in the understanding of the design bynon-engineers and management

Objectives

The objective of this project is to demonstrate the use of the tools of simulation-based design to create a virtual prototype structure, the associated synthetic environment into which the prototype is immersed, and the interaction of mechanical simulations in the virtual environment and prototype.

Applications

Navy ships

Commercial ships

Petrochemical platforms

Design review classification societies such as American Bureau of Shipping

Aeronautical structures

Automobile industry

Development Partners

Mechanical Dynamics Inc.

Dynamic Animation Systems

Deployment Partner

McDermott Shipbuilding Inc.

Project Status Summary

1) Fly-through of MOB visualization
The first phase of the project involved assembling the software tools necessary to execute the tasks outlined by McDermott Shipbuilding Inc.  Due to the complexity of the tasks, four different commercial-off-the-shelf software packages were selected. Thereafter,  product model information was received and converted to a photo-realistic visualization of the MOB.  A story-board detailing an accurate depiction of a fly-through of the structure and culminating with the landing of fully-loaded C-130 and C-17 cargo plane was performed.  This story-board was saved as a video of computer-generated graphics.

2) Induced MOB motion visualization
This task involved visualizing the MOB in various sea states.  Motion representations were accomplished through multiplying the response amplitude operators (RAO) by the frequency-domain matrix representation of the sea state, and converting from frequency to time domain for display.  Additionally, the flight path from task 1 was repeated and the entire output of computer-generated frames was saved as a video. A training session to transfer the lessons learned in this phase was conducted for McDermott Shipbuilding Inc.

3) Induced MOB and auxiliary ship motion visualization
Building on the simulations done in task 2, this phase includes the absolute and relative motions of two different auxiliary ships (supply and landing craft) seen in a variety of sea states in the vicinity of the MOB.  A second training session to transfer the lessons learned in this phase was conducted for McDermott Shipbuilding Inc.

4) Virtual ocean and operational simulation visualization
This phase incorporates the synchronization of the motion of the virtual ocean with the motion of the MOB and auxiliary vessels including the mechanical simulations of the cargo handling routines.  All of these sequences build on task 3 and will be photo-realistic representations that are appropriately visualized and output to a CD-ROM.  In order to accomplish the ocean and vessel motions, a custom interface was added onto the visualization software.  Finally, a third training session to transfer the knowledge on lessons learned will be held for McDermott Shipbuilding Inc.

Contact

Mr. John Cardner
(409) 882-3054
E-mail cardner@luorc.edu

GCRMTC TECHNICAL BRIEFS are published periodically by the Gulf Coast Region Maritime Technology Center, a U.S. Navy Center of Excellence in Advanced Marine Technology based at the University of New Orleans.  GCRMTC's Mission is to "enhance international competitiveness in the U.S. shipbuilding industry through sponsored research."   For additional information, contact:  GCRMTC, University of New Orleans, New Orleans, LA 70148, Tel: (504) 280-3871, Fax: (504) 280-3898, E-mail: jtsen@uno.edu

The contents of this publication reflect the views of the MERIC staff and are based on information obtained from the literature.  The contents do not necessarily reflect the official views or the policies of MERIC or the Gulf Coast Maritime Technology Center.  This publication does not constitute a standard, specification, or regulation.  MERIC does not endorse products, equipment or manufacturers.  Trademarks or manufacturer's names appear herein only because they are considered essential to the object of this publication.