Mechanical engineers are for the most part known as device engineers, which amounts to design and manufacturing of what we call components. Marine engineers on the other hand are for the most part engaged in assembling components to form a system. That means that for the marine engineer, it is not sufficient to pay detailed attention to the design of the various elements or components which go to make up an overall system, it is also important to consider the elements in relation to each other. This is what we call a "system viewpoint". Thus, the essence of marine engineering is that it is concerned with the design and operation of a complete system rather than with just the operation of the component parts. That is, to make sure that not only will the parts of the system work, but also the system as a whole will perform its intended function. Even if each element or subsystem is optimized from a design or operational viewpoint, the total-system performance may be sub-optimal owing to interactions between the parts. That is, perfectly good components can be assembled into an unsatisfactory system. For example a propulsion system experiencing excessive torsional vibration stresses has a "system complain" since the different parts functions just as the designers had hoped they would. This means that the main emphasis should be on studying system aspects and marine engineers should have a reasonable command of several of the engineering sciences.
3. SYSTEM VIEWPOINT
Generally system studies are of three main types, namely
・establish system specifications
・system design
・system analysis
In system design studies, the object is to develop a system concept, which is believed to satisfy the set of specified or implied requirements. System analysis aims to understand how a proposed or existing system operates which means predicting the behavior at the design stage in order to test a concept to its capacity to satisfy demands placed on it.
System analysis can again, in general, be divided into two broad aspects
・Modelling theory - the process of generation a model of the system from a defined structure.
・Behavior theory - the process of analysis, the solution, characteristics of the system model to simulate the physical behavior of the system as a function of a change in the structural features and compare the predicted performance to the performance s pacifications.
The role of analysis or experimentation in device engineering and marine system engineering provides a contrast. The device engineer can usually experiment readily with his actual device, but experimentation with marine engineering systems is almost impossible. Thus, to be certain of the overall performance before it is built, mathematical models, computer studies and computer simulation is the only realistic method of experimentation, In other words, from a system design viewpoint we can treat the simulation as if it were done experiments on the actual system and make changes to parameters, structure of the model and proposed manipulations and operating conditions. Simulation is therefore, an experimental and applied methodology, which seeks to predict future behavior, that is, the effect that will be produced by changes in the system or in its method of operation. Simulation can be perceived as a bridge between design and operation.
Also, an important use of simulation is learning. There is no better way to learn the behavior of systems than to experiment with a model of a real-world system. Syn YatSen "Father of the Chinese Republic" is reported to have said:
"To understand is hard, once one understands, action is easy".
Simulation is a powerful tool for alleviating the "hard" problem by improving understanding.
The subject of simulation has a prominent place in technology, but examination of engineering university curricula does not yield this conclusion.
Marine engineers of tomorrow will most likely be expected to supply quantitative system performance predictions at the design stage. The only feasible way to obtain such predictions for systems is through simulation technology.
The Finite Element method has revolutionized structural design and analysis. Simulation techniques can become the same revolution for marine engineers as system designer. In order for this to happen, marine engineers must be educated to bring this technology into use. This again means that the academic community must take the challenge to develop an academic program that lifts the use of simulation from being an academic exercise to a useful industrial tool.
4. SIMULATION AND MODELLING
Simulation as a problem solving methodology consists of three important phases
・Modelling
・Numerical analysis
・Conducting experiments with a model
In an engineering curriculum, mathematics and numerical methods are taught but not sufficiently applied to real world problems. Numerical software and powerful computers are available. The challenge is for educators to use these tools in developing well-learned marine engineer who know how to use the computer as necessary engineering tool and, who also know how to interpret the results.
One of the biggest problems in applying simulation to the study of systems is that of creating a mathematical model. Modelling is often through of "simply" as a process involving the application of physical laws and principles to establish a set of equations which describe a given system. Looking through the literature on the subject it appears that it is not "simply", but reveals to enormous diversity of approaches used as hence the difficulties associated with developing relevant computable models and in a form which engineers can comprehend and understand. In spite of this fact, the means for constructing a suitable model is often given very little attention in the literature or in engineering education. It can be argued that all intellectual activities involve modeling of sorts since we always make conceptual simplifications in order to comprehend a real, world object. The construction of models with an acceptable validity requires a profound understanding of the system being modeled and the area or discipline to which it belongs. The modeling process is by no means to be divorced from the physical processes to which it is applied.
