Aluminum In Marine Construction

Abstract

ABSTRACT This paper is presented to give a progress report on the state-of-the arts of aluminum as a marine construction material. Aluminum has been used in marine environment over a number of years but its acceptance as a basic construction material has been relatively slow, mostly because it requires different fabricating techniques. Aluminum is a versatile construction material which offers high strength, light-weight and corrosion resistance of the first magnitude and can be readily welded and fabricated. It also offers the designer advantages and freedoms seldom encountered in other metallic construction materials. To the owner and operator it offers advantages of economic importance. In the case of floating marine structures it can improve stability, increase dead weight, reduce draft, minimize maintenance, increase speed. In the case of stationary structures it offers reduced maintenance cost and decreased erection costs. It is the purpose of this paper to familiarize the technical community of the advantages that aluminum has to offer in the area of marine construction which have been neglected during the past and will point out how this versatile material can be advantageously used in marine environment. INTRODUCTION Selecting the proper material has become one of the more important steps in the design process of products. This is even more true today as we are witnessing the emergence of a galaxy of new materials which are the result of the technology explosion that is presently taking place. It was not so long ago, and may hold true in some areas even today, when materials selection was done rather casually. The general procedure was to rely almost or entirely on past experience and pick a design of a product keyed to the properties of the few materials with which the engineer and designer were familiar. It is the essential task of the designer to provide a structure to convey a specified system of loads over a given spatial map. In the past when selecting materials for a given structure the designer looked at properties such as the ultimate and yield strength, elongation, the moduli of elasticity of torsion and, in some cases, its specific weight. In recent years, the rise of new and more severe service requirements and the demand for greater reliability and lower costs have required the designer to utilize to the maximum extent the inherent properties of the construction material which he uses for his structures. This necessitates an examination of the properties of the construction material at elevated as well as cryogenic temperatures, ordinary corrosion and stress corrosion, fracture toughness, fatigue and fatigue crack propagation, short transverse strength, weldability, machinability and many others. In other words, the designer's task and responsibility have expanded where he must come up with products at the outset, on the drawing board, which minimize problems in production, optimize the utility and reduce the maintenance to a minimum of his creation. With proper materials selection he can, borrowing expressions from another scientific discipline, practice preventive rather than therapeutic medicine.