Structural Design of Mid-Ship Section by Expert System

Abstract

Since many design variables affect each other for ship structural design, it is difficult to decide them all at one time. Generally, a large number of trials in updating those variables is necessary to complete the design in order to satisfy the requirements by a customer and some other conditions. Hence, constructing expert systems for helping ship structural design have been desired these days.In this paper, the expert system for aiding constructing a bulk-carrier is studied with emphasis upon the structural design of the midship section. The expert system is written in LISP which makes it possible to have more consultative and interactive systems. A knowledge base is called for deciding design variables, which are checked in a rule base and are updated until all conditions are satisfied. After assuming the initial design variables at the midship section with satisfying NK-rules locally, the longitudinal strength of the section is computed. An optimization technique is developed for obtaining the required longitudinal strength at the midship section in which the minimum weight is chosen to be an objective with handling the design variables as discrete numbers.For an illustration of the system, a bulk-carrier is designed. The procedure of deciding the midship section is demonstrated in this paper which started from the two requirements such as “dead weight” and “speed of ship”. In order to check the efficiency of the created system, the midship section is compared with one having the same principal requirements.