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Über dieses Buch

Welcome to Bavaria - Germany and to the First Intercontinental Maritime Simulation Symposium and Mathematical Modelling Workshop. A triennial international conference jointly pro­ moted by Control Data, IMSF and SCS, which takes place at Schliersee, a small town near the Alps. The aim of the Symposium is to cover most of the aspects of maritime modelling and simulation in theory and practice, to promote the exchange of knowledge and experience between dif­ ferent international research groups in this field, and to strengthen the international contact between developers and users of modelling and simulation techniques. On the occas~on of the Symposium people of scientific and engineering disciplines will meet to discuss the state-of-the­ art and future activities and developments. A large number of contributed papers has been strictly exam­ ined and selected by the papers committee to guarantee a high international standard. The book contains the accepted papers which will be presented at the Symposium. The papers have been classified according to the following topics: VI 1. Fifth Generation Computer Technology 2. Simulation-Software-Tools 3. An Industrial Computer System - The Chrysler Story 4. Marine Mathematical Modelling 5. CFD for Marine Vehicles 6. Navigation Methodology 7. Marine Maneuvering and Motion Simulation 8. Off-Shore Modelling 9. Steering and Control of Marine Vehicles 10. Training and Traffic Control 11. Under-Water Vehicles Operation Authors from 9 countries will meet at the Symposium.

Inhaltsverzeichnis

Frontmatter

Introduction Simulation “In the Boat”

Introduction Simulation ≫In the Boat≪

Abstract
Before the widespread use of the digital machines, relationships and activities in the scientific-engineering approach were largely determined by the human mind, its formalization and analytic powers. The scientist or engineer who approaches a real world process tries to gain insight or an understanding of the phenomena on the process under study. One of the very powerful methods consists in trying to obtain an abstract or formal model or representation of the process. The activity is defined as model building and formalization. In essence the procedure requires abstraction and simplification. Simplification is necessary to restrict the complexity of the representation. One only chooses those properties within given boundaries of space or time which are believed to be connected with each other but unconnected with other properties or other parts of the world. Basically the model builder proceeds by hypothesis, induction and deduction. The complete body of methods is called modelling methodology.
M. R. Heller

Fifth Generation Computer Technology

Frontmatter

The Introduction to Parallel Processing to Solve Future Applications

Abstract
Parallel Processing is an old methodology, and is now becoming part of the design of new applications. The evolution of VLSI technology and the parallel processing software has provided a base technology for commercial organizations to introduce high parallel processing into the marketplace.
Wayne A. Ray

Supercomputers and Mathematical Modeling

Abstract
The rise of supercomputers and the role in mathematical modeling is discussed with examples from error dynamics, electronic circuits and numerical linear algebra.
The supercomputer has been variously defined as:
1.
A computer with the fastest processor able to address the most memory.
 
2.
A computer with the capability only one order of magnitude less than current scientific/ technological requirements.
 
3.
A computer that cost ten million dollars.
 
Though definition 2 may be whimsical, and definition 3 perhaps facetious, a glance at figure 1 indicates that definitions 1 and 3 seem to jibe at least in recent times. That definition two is also valid remains to be seen. In any case definition 1 implies that supercomputers have always existed although the term is of recent coinage.
G. V. Tarsy

CYBERPLUS, a High Performance Parallel Processing System

Abstract
The CYBERPLUS is a High Performance Parallel Processing System offered by Control Data Corporation and provides a capability for large scale simulations that are not available with other uniprocessor systems or systems containing special purpose array or attached processors.
Wayne A. Ray

Simulation — Software — Tools

Frontmatter

A Contribution on Calculating Vibrations in Coupled Rigid and Elastic Multibody Systems Applied to a Propulsion System — An Application of the Computer Program MEDYNA

Summary
Taking a ship propulsion system as an example, it will be shown how vibration analysis could be performed by means of the simulation program MEDYNA even in the design phase.
Vibration calculation of a complete propulsion system and thus a system of coupled rigid and elastic bodies is primarily of importance when considering a long, slender ship structure with “weak stern constructions”. Such designs are to be found in the field of naval vehicles.
Besides the general eigenvalue analysis the forced vibration due to propeller forces will be considered.
D. Karius, W. Kortüm

Recent Innovations to CSSL-TV

Summary
CSSL-IV (Continuous System Simulation Language — version four) provides the most advanced tools available for the modeling and simulation of dynamic systems. Version 4.3, released first quarter this year (1985) has added a complete Linear Algebra Subsystem, several new Graphic Features, over 30 new Simulation Operators, new Integration Algorithms with stiffness detection and automatic algorithm selection, a Linear System Analysis Subsystem plus improved performance and extended availabi1ity.
R. N. Nilsen

The Role of Computer Graphics in Maritime Simulation

Summary
Computer graphics constitutes a very powerful and direct interface between a simulation system and its operator. The constraints imposed on a computer graphics system by the special demands of maritime simulation are not very severe. Motions are mostly slow, however, a multitude of display devices is necessary. Depending on the amount of realism wanted some special features for scene display can be realized. Special systems for radar and control-system simulation need only line graphics and standard techniques.
D. Ridder

Industrial Computer System — The Chrysler Story

Frontmatter

Simulation Tools for Chrysler Product Development

Summary
Chrysler Corporation’s product design and development efforts rely heavily on an extensive network of computers for computer-aided design, engineering, manufacturing, and testing (CAD/CAE/CAM/CAT). Since virtually all proposed vehicle goemetry is stored on the system, it can be used for engineering applications such as structural analysis, crash simulation, and aerodynamic computations. This paper describes the computer environment at Chrysler and the techniques being developed to support crash and aerodynamic simulation on Chrysler’s CYBER 205 computer.
R. A. Brauburger

Marine Mathematical Modelling

Frontmatter

On the Construction of a Versatile Mathematical Model for Marine Simulation

Summary
A mathematical model consisting of coupled equations for surge, sway, yaw, roll and propeller revolutions has been assembled for the prediction of ship manoeuvrability at the design stage. All input data describing the ship can be obtained without resource to model experiments, making the use of the method inexpensive and quick. The mathematical model reproduces full-scale manoeuvres with satisfactory accuracy and it is thus an ideal tool for Marine Simulation.
N. E. Mikelis, A. J. P. S. Clarke, S. J. Roberts, E. H. A. J. Jackson

Direction of International Joint Effort for Development of Mathematical Models and Ship Performance Data for Marine Simulation Applications

Abstract
This paper discusses international joint efforts to promote a more efficient use of the valuable and costly inventory of ship maneuvering data of different test and simulation facilities. A new concept is presented which allows a simulation facility to more effectively implement a specific ship model based on a standardized data package provided from another facility that has a validated mathematical model in operation. The concept resolves problems with math commonality and significantly reduces costs by minimizing duplication of effort.
Joseph J. Puglisi, John S. Case, Wei-Yuan Hwang

CFD for Marine Vehicles

Frontmatter

The Computation of Flow Around Ships with Allowance for Free-Surface and Density-Gradient Effects

Abstract
It has been possible for several years to obtain solutions of the Navier-Stokes equations by numerical means, and only the cost of doing so has delayed large-scale use of the methods for predicting the flow around surface and submarine vessels.
D. Brian Spalding

Large-Scale CYBER-205 Simulation of Vortex Flowfields Around Submarines

Abstract
There is great practical incentive to simulate by computer the flow around a submarine. Potential models currently in use are limited in their treatment of separation. According to Maskell’s classification the flow leaves the surface in either a bubble-type (closed streamline) separation or a free- shear-layer (open streamline) separation. We hypothesize that open separation is an inviscid but rotational phenomenon that is correctly described by the incompressible Euler equations. The large-scale numerical simulation using over 600,000 computational cells which is presented here for flow around a 9.5:1 ellipsoidal body supports the conjecture.
Arthur Rizzi, Charles J. Purcell

Navigation Methodology

Frontmatter

Simulation of a Digital Filter/Estimator for the Navigation of Large Ships in Confined Waters

Summary
Aeronautical and marine casualty statistics indicate that the human being, when under stress or at times of peak load, can be a poor co-ordinator of the information available to him, particularly when that information is from a number of different sources, as is often the case in modern ships. Integration and co-ordination of information and its useful application in a closed loop feedback system can reduce the probability of accident as has already been demonstrated in the case of automatic landing systems for aircraft.
This paper describes the development of a digital fi1ter/estimator for use in conjunction with an optimal controller in the navigation of large ships in the approaches to a port.
M. J. Dove, R. S. Burns, C. T. Stockel, T. H. Bouncer

Marine Maneuvering and Motion Simulation

Frontmatter

Marine Maneuvering Simulation

Abstract
To provide guidance to any potential buyer of a major Marine Manuevering Simulator, the following outline of recommendations and specifications is offered. The items included could, considering any vessel characteristics, satisfy in terms of “feel and visual accuracy”, the fidelity that ship’s simulation demands.
Max H. Carpenter

A Discrete, Time Varying, Non-Linear Mathematical Model for the Simulation of Ship Manoeuvres

Summary
This paper considers the development of a discrete, time-varying non-linear mathematical model for a ship based upon eight state variables. There are two deterministic inputs - demanded rudder and engine speed plus four stochastic inputs in the form of wind and current vectors. The model is validated by conducting a comprehensive simulation study using known linear and nonlinear hydrodynamic coefficients for a full-size vessel. A comparative evaluation of simulated results against real data is undertaken for a set of standard manoeuvres. It is demonstrated that a non-linear, time-varying multivariable model accurately describes the motion of the hull, particularly in tight manoeuvres.
R. S. Burns, M. J. Dove, T. H. Bouncer, C. T. Stockel

Modeling and Simulation of the Roll Motions of a Ship

Abstract
At the Control Laboratory of the Electrical Engineering Department of Delft University of Technology much research has been carried out during the last 15 years in the field of ship control systems, with the main emphasis on automatic steering of ships. At the moment, the research is concentrated on the design of an autopilot which uses the rudder not only for course keeping but also for roll stabilization, where mostly stabilizing fins have been used up to now. Modeling experiments were carried out and based on their results a simple model of a ship describing the transfer between the rudder and the yaw motions was obtained. The model was subsequently used to design a Rudder Roll Stabilization, RRS, autopilot.
The autopilot was extensively tested with two types of digital computer simulations and their results were verified with scale-model experiments in open water and full-scale trials with a ship of the Royal Netherlands Navy. The experiments demonstrated that an RRS autopilot, designed and tested by means of digital computer simulations, is able to realize roll reduction during full-scale trials comparable to that achieved by computer simulations. This makes it attractive to examine new ship designs with respect to the applicability of an RRS autopilot by means of computer simulations. This paper reports the results of these experiments.
J. van Amerongen, P. G. M. van der Klugt

A Modular Manoeuvring Mathematical Model for Warship Simulation

Summary
The changing pattern of usage of ship simulators over the past few years is examined, and the trend towards individual projects noted. The need for more flexible ship manoeuvring mathematical models is then discussed, and the developemnt of a particular model, representing two warship types, is briefly described. Towing tank tests were used to augment the limited full scale results available. Validation of the model is discussed, and a proposal for international definition of agreed mathematical model sub-system interfaces made.
I R McCallum, R. Matthews

Off-Shore Modelling

Frontmatter

ABAQUS/AQUA Application to Offshore Risers and Pipelines

Abstract
This paper outlines the capabilities of the AQUA subset of the ABAQUS (1) finite element program for simulating marine risers and pipelines under operational conditions. The AQUA suite is used mainly for nonlinear cases, the nonlinearities being due to the fluid loading and the large motions and stresses in the piping structures. Typical examples include the response due to waves and currents in deep water drilling and production risers; mooring lines; flexible risers and tanker loading hoses; tension leg tethers; offshore mining pipes; and the towing, drawdown and installation of long strings of piping. AQUA also models the J-tube pull operation, with rigid or flexible J-tubes.
J. F. Mc Namara, J. P. Gilroy, E. P. Sorensen, H. D. Hibbitt

Steering and Control of Marine Vehicles

Frontmatter

Steering Control Algorithms for a Submersible

Abstract
This paper describes the algorithm design of a steering system for control of the depth and the course of a manned submersible.
The control algorithms will be implemented into a general purpose military computer system which enables application of control techniques such as:
  • optimal linear quadratic control;
  • feed forward control and mode switching;
  • gain scheduling for the speed;
  • adaptive Kalman filtering;
  • estimation of slowly varying disturbances.
The decoupled course and depth control algorithms use simplified control models, respectively based upon a fourth order linear approach of the depth behaviour and an extended first order Nomoto model for the course behaviour.
L. A. M. Kuijk, G. B. H. Jacobs, B. Twigt

Training and Traffic Control

Frontmatter

Simulation and Pilot Training at the Panama Canal

Summary
Several years ago, the Panama Canal Commission began to have concern about its ability to adequately train pilots in the future. There were several sound reasons for this disquietude. The emergence of the shiphandling simulator appeared to offer relief. Following a somewhat exhaustive investigation, the Canal management elected to tentatively supplement the regular training with a course of instruction on a shiphandling simulator. The reasons for the choice of facilities as well as the problems in the development of a viable and acceptable (to the pilots) program are discussed. The present status of the program and the role of the micro-simulator in that program are also presented in this paper.
Robert D. Valentine

Micro-Computerized Maritime Traffic Simulator

Summary
This paper describes a micro-computerized maritime traffic simulator, which reproduces the behaviour of a given traffic flow display of most modern Vessel Traffic Services.
This tool can be used in the three following subjects:
  • study of traffic organization in a given sea area,
  • testing new solutions as far as surveillance and information to navigation are concerned,
  • training for VTS radar operators.
T. Degre, X. Lefevre

The Minimum Manoeuvering Range as a Criterion to Evaluate the Risk of Collision Between Ships

Abstract
To evaluate the risk of collision between two ships in a hazardous encounter, it is necessary to establish a criterion which quantifies the danger for the involved ships.
For this purpose the Minimum Maneuvering Range seems to be a suitable parameter. It describes the minimum distance from the other ship, which one ships needs to avoid a collision, when starting her evasive maneuver. To calculate the Minimum Maneuvering Range and the corresponding evasive maneuver the
  • actual maneuverability of the own ship and
  • possible maneuvers of the other ship have to be taken into account.
Two methods to solve this problem are considered.
The results for several encounters of two ships with variable rudder application are computed. A simple and definite representation of the necessary maneuvering range and actions on the radar display is suggested.
Bernd Hampel

The Measurement and Assessment of some Critical Skills of Mariners on CGI Shiphandling Simulators. Can the Mathematical Models meet the Demand?

Summary
The advent of the CGI shiphandling simulator has led to the development of extensive training programmes for Mariners in many aspects of seamanship and navigation. As a -further development, this paper looks at the way in which the technology may be used to supplement existing methods of assessment of certain practical skills, and asks if the tests on which most models are validated, are sufficiently broad in scope to meet such a demand. The author has drawn upon some experiences gained from current programmes being researched at UWIST,Cardiff, and SUSAN, Hamburg.
P. M. P. Muirhead

Under-Water Vehicles Operation

Frontmatter

A Simulator for Remotely Operated Underwater Vehicles

Summary
This paper outlines the future need of simulation techniques for Remotely Operated underwater Vehicles (ROVs).
Simulation techniques are here applied to predict the manoeuvring behaviour of a ROV. The derivation of the mathematical models is described. It is further shown how these mathematical models are implemented on a microcomputer, and how these are integrated for application in a basic simulator.
G. K. Kapsenberg

The Program DYSMAS/ELC and its Application on Underwater Shock Loading of Vessels

Abstract
The simulation of highly dynamic processes concerning structural response, fluid dynamics and the behavior of coupled systems can advantageously be managed by an explicit finite formulation, which is able to handle the various nonlinearities appearing in the wide field of short-time physics. The program family DYSMAS has been developed step by step in connection with a great number of projects mostly in the field of defense technology. The DYSMAS code consists of the two stand alone processors DYSMAS/L, a FE-Lagrangian code, and DYSMAS/E, a FD-Euler ian code and additionally of DYSMAS/ELC in which both are coupled together in 2D and 3D.
The code takes into account large displacements and distortions by the formulation of the basic equations. Its extensive material description allows the treatment of large plastic flow including work hardening and strain rate dependency, as well as material failure and post-failure-behavior using progressive methods such as crack-opening or erosion models. The 3D multibody contact processor enables the DYSMAS-user to simulate impact, penetration and crash problems. Especially fluid-structure-interaction phenomena are distinguished by nonlinearities present both in structure and in fluid. The low compressibility of water in compression and its cavitation properties under tension have great influence on the transient loading of vessels subjected to underwater detonations.
In the recent years DYSMAS/ELC was applied to the simulation of a lot of underwater detonations against various ships and submerged structures. As an example this report covers the evaluation of a torpedo shot in the nearfield of a frigate- sized ship. The investigation embraces the detonation shock wave and its propagation in the fluid and in the structure as well as the mechanical damage to the ship hull, caused by the shock wave and by the dynamic pressure due to the gas-bubble- expansion. The results comprise the assessment of damage on equipment based on the evaluation of the shock-spectra, which enable the analyst to make a decision about the residual serviceability of the total system or subsytems.
DYSMAS/ELC at present is also used to simulate soil-structure interaction phenomena as for instance the detonation of buried charges against a shelter structure or terminal ballistics phenomena including ricochetting of projectiles on soil or fluid.
W. Bergerhoff, W. Mohr, W. Pfrang, F. Scharpf
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